2008 Vol. 5, No. 3
Display Method:
2008, 5(3): 131-136.
Abstract:
Background and objective The value of D-dimer in the risk stratification of patients with coronary artery disease(CAD) and the relationship between D-dimer and the diseased coronary arteries remains controversial or unclear, especially in the elderly. This study was to evaluate the usefulness of D-dimer as a biomarker in assessing the vulnerable blood in the elderly patients with coronary disease. Methods Sixty elderly (≥60 years old) male patients with suspected CAD were enrolled in this prospective study. Patients were divided into CAD group (n=41, 10 with stable angina and 31 with unstable angina) and control group (n=19) according to their coronary angiography Results Clinical information including age, body mass index (BMI), smoking index, and the complications of primary hypertension or diabetes, and CAD family history was collected. Venous blood was sampled serially for the determination of total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, apoA1, apoB, glucose, uric acid, homocysteine (Hcy), hs-CRP, soluble thrombomodulin (sTM), and markers of fibrinolytic system and hypercoagulability, such as D-dimer, fibrinogen, etc. The extent of coronary atherosclerosis was assessed, using the Gensini scoring system on the basis of coronary angiography. Results Compared with the controls, the patients with CAD had significantly higher levels of D-dimer. D-dimer level was significantly correlated to age, hs-CRP, Hcy, and PAI-1. Patients with D-dimer levels in the top triplicate of D-dimer level had significantly higher prevalence of unstable angina compared with patients in the lowest triplicate (OR=4.8, Z=3.28, P=0.001). In an ordinal logistic regression, the OR value of developing more serious CAD augmented 3.1-fold with each increasing triplicate of D-dimer. Patients with unstable angina had a significantly higher level of D-dimer than the controls (P=0.005), and an increasing trend compared with patients with stable angina (P=0.059), whereas there was no difference between the patients with stable angina and the controls (P=0.885). D-dimer was significantly correlated with Gensini scores (r=0.3930, P=0.0019). Ordinal logistic regression showed that the OR value of increasing one or two triplicates of Gensini’s scores augmented 1.44-fold with each increasing triplicate of D-dimer (OR=2. 44, Z=2.87, P=0.004). Conclusions D-dimer may be a helpful biomarker in identifying the severity of vulnerable blood in elderly patients with CAD.
Background and objective The value of D-dimer in the risk stratification of patients with coronary artery disease(CAD) and the relationship between D-dimer and the diseased coronary arteries remains controversial or unclear, especially in the elderly. This study was to evaluate the usefulness of D-dimer as a biomarker in assessing the vulnerable blood in the elderly patients with coronary disease. Methods Sixty elderly (≥60 years old) male patients with suspected CAD were enrolled in this prospective study. Patients were divided into CAD group (n=41, 10 with stable angina and 31 with unstable angina) and control group (n=19) according to their coronary angiography Results Clinical information including age, body mass index (BMI), smoking index, and the complications of primary hypertension or diabetes, and CAD family history was collected. Venous blood was sampled serially for the determination of total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, apoA1, apoB, glucose, uric acid, homocysteine (Hcy), hs-CRP, soluble thrombomodulin (sTM), and markers of fibrinolytic system and hypercoagulability, such as D-dimer, fibrinogen, etc. The extent of coronary atherosclerosis was assessed, using the Gensini scoring system on the basis of coronary angiography. Results Compared with the controls, the patients with CAD had significantly higher levels of D-dimer. D-dimer level was significantly correlated to age, hs-CRP, Hcy, and PAI-1. Patients with D-dimer levels in the top triplicate of D-dimer level had significantly higher prevalence of unstable angina compared with patients in the lowest triplicate (OR=4.8, Z=3.28, P=0.001). In an ordinal logistic regression, the OR value of developing more serious CAD augmented 3.1-fold with each increasing triplicate of D-dimer. Patients with unstable angina had a significantly higher level of D-dimer than the controls (P=0.005), and an increasing trend compared with patients with stable angina (P=0.059), whereas there was no difference between the patients with stable angina and the controls (P=0.885). D-dimer was significantly correlated with Gensini scores (r=0.3930, P=0.0019). Ordinal logistic regression showed that the OR value of increasing one or two triplicates of Gensini’s scores augmented 1.44-fold with each increasing triplicate of D-dimer (OR=2. 44, Z=2.87, P=0.004). Conclusions D-dimer may be a helpful biomarker in identifying the severity of vulnerable blood in elderly patients with CAD.
2008, 5(3): 137-141.
Abstract:
Background and objective Pre-operative assessment of mitral valve (MV) anatomy is essential to surgical design in patients undergoing MV repair. Although 2-dimensional (2D) echocardiography provides precise information regarding MV anatomy, RT-3D TEE could increase the understanding of MV apparatus and individual scallop identification. We aimed to investigate the value of RT-3DTEE in MV repair. Methods RT-3DTEE was performed in six patients with mitral valve prolapse (MVP) by using Philips IE33 with X7-2t probe. Preoperative RT-3DTEE studies were compared with surgical findings in patients undergoing surgical mitral valve repair, and quantitative evaluation was performed by QLab 6.0 software before and after surgical mitral valve repair. Results RT-3DTEE could display dynamic morphology of MV, the location of prolapse, and spatial relation to the surrounding tissue. It could provide surgical views of the valves and the valvular apparatus. These results were consistent with surgical findings. The quantitative evaluation before and after surgical MV repair indicated that anterolateral to posteromedial diameter of annulus, anterior to posterior diameter of annulus, perimeter of annulus, and area of annulus in projection plane were significantly smaller after operation compared with those before operation (P<0.05). The length of posterior leaflet, the area of anterior and posterior leaflet, the maximal prolapse height, the volume of leaflet prolapse and the length of coaptation in projection plane were significantly reduced after operation (P<0.05). Conclusion RT-3DTEE is a unique new modality for rapid and accurate evaluation of mitral valve prolapse and mitral valve repair.
Background and objective Pre-operative assessment of mitral valve (MV) anatomy is essential to surgical design in patients undergoing MV repair. Although 2-dimensional (2D) echocardiography provides precise information regarding MV anatomy, RT-3D TEE could increase the understanding of MV apparatus and individual scallop identification. We aimed to investigate the value of RT-3DTEE in MV repair. Methods RT-3DTEE was performed in six patients with mitral valve prolapse (MVP) by using Philips IE33 with X7-2t probe. Preoperative RT-3DTEE studies were compared with surgical findings in patients undergoing surgical mitral valve repair, and quantitative evaluation was performed by QLab 6.0 software before and after surgical mitral valve repair. Results RT-3DTEE could display dynamic morphology of MV, the location of prolapse, and spatial relation to the surrounding tissue. It could provide surgical views of the valves and the valvular apparatus. These results were consistent with surgical findings. The quantitative evaluation before and after surgical MV repair indicated that anterolateral to posteromedial diameter of annulus, anterior to posterior diameter of annulus, perimeter of annulus, and area of annulus in projection plane were significantly smaller after operation compared with those before operation (P<0.05). The length of posterior leaflet, the area of anterior and posterior leaflet, the maximal prolapse height, the volume of leaflet prolapse and the length of coaptation in projection plane were significantly reduced after operation (P<0.05). Conclusion RT-3DTEE is a unique new modality for rapid and accurate evaluation of mitral valve prolapse and mitral valve repair.
2008, 5(3): 142-145.
Abstract:
Objective To evaluate the safety and possibility of transesophageal emergency ventricular pacing with esophageal balloon electrode catheter. Methods Sixty four patients with critical bradyarrhythmias were divided randomly to receive either transesophageal ventricular pacing with esophageal balloon electrode catheter (balloon catheter group, n=32), or transesophageal ventricular pacing with normal esophageal electrode catheter (normal catheter group, n=32). Pulse width (ms), current output (mA), and the success rate were compared between the 2 groups. Results Success rate in the balloon catheter group was 87.5%, which was significantly higher than that in the normal catheter group (18.7%, χ2=27.7, P<0.01). The success rate of transesophageal ventricular pacing with esophageal balloon electrode catheter was 87.5%. The average current output (mA) was significantly lower in the balloon catheter group than that in the normal catheter group (24.5±2.5 mA vs 53±3.4mA, P<0.05). Conclusions Esophageal balloon electrode catheter pacing could become an available technique for transesophageal emergency ventricular pacing.
Objective To evaluate the safety and possibility of transesophageal emergency ventricular pacing with esophageal balloon electrode catheter. Methods Sixty four patients with critical bradyarrhythmias were divided randomly to receive either transesophageal ventricular pacing with esophageal balloon electrode catheter (balloon catheter group, n=32), or transesophageal ventricular pacing with normal esophageal electrode catheter (normal catheter group, n=32). Pulse width (ms), current output (mA), and the success rate were compared between the 2 groups. Results Success rate in the balloon catheter group was 87.5%, which was significantly higher than that in the normal catheter group (18.7%, χ2=27.7, P<0.01). The success rate of transesophageal ventricular pacing with esophageal balloon electrode catheter was 87.5%. The average current output (mA) was significantly lower in the balloon catheter group than that in the normal catheter group (24.5±2.5 mA vs 53±3.4mA, P<0.05). Conclusions Esophageal balloon electrode catheter pacing could become an available technique for transesophageal emergency ventricular pacing.
2008, 5(3): 146-149.
Abstract:
Objective Recent studies reveal important roles of platelet P-selectin on progression of atherosclerosis. In the present study, we examine the relation between platelet P-selectin expression and severity of acute coronary syndromes. Methods One hundred and eighty-four consecutive patients with proven or clinically suspected acute coronary syndromes (ACS) were enrolled in the study. Level of P-selectin expression was determined by flow cytometry. Platelet P-selectin level was expressed as the percentage of Pselectin positive platelet. Results The level of P-selectin was higher in patients with a single diseased coronary artery or multiple diseased arteries compared to those with normal coronary arteries. P-selectin expression was significantly and positively correlated with angiographic Gensini score (r=0.323, P=0.029). Multiple regression analyses showed that the association of the percentage of Pselectin–positive platelets with ACS was independent of other clinical factors. Conclusions Platelet P-selectin is associated with severity of acute coronary syndromes in patients with acute coronary syndromes.
Objective Recent studies reveal important roles of platelet P-selectin on progression of atherosclerosis. In the present study, we examine the relation between platelet P-selectin expression and severity of acute coronary syndromes. Methods One hundred and eighty-four consecutive patients with proven or clinically suspected acute coronary syndromes (ACS) were enrolled in the study. Level of P-selectin expression was determined by flow cytometry. Platelet P-selectin level was expressed as the percentage of Pselectin positive platelet. Results The level of P-selectin was higher in patients with a single diseased coronary artery or multiple diseased arteries compared to those with normal coronary arteries. P-selectin expression was significantly and positively correlated with angiographic Gensini score (r=0.323, P=0.029). Multiple regression analyses showed that the association of the percentage of Pselectin–positive platelets with ACS was independent of other clinical factors. Conclusions Platelet P-selectin is associated with severity of acute coronary syndromes in patients with acute coronary syndromes.
2008, 5(3): 150-154.
Abstract:
Objectives To study the relationship between plasma hemoglobin concentration and estimated glomerular filtration rate (eGFR) in elderly patients with ischemic cardiomyopathy (ICM). Methods Clinical data of patients with coronary heart disease who were discharged from The First Affiliated Hospital, Chongqing Medical University between 2005 and 2007 were analyzed retrospectively. Echocardiography results, plasma hemoglobin and creatinine concentration were abstracted from the medical records. The study included 235 Chinese Han patients with age 60 years and older with angiography confirmed coronary heart disease, silent myocardial ischemia or angina pectoris, of whom 154 had ICM defined as left ventricular end-diastolic diameter (LVDd), male≥56 mm, female ≥51 mm (63.51±7.70 mm) measured by M-mode echocardiography. The differences in plasma hemoglobin concentration were analyzed retrospectively between patients with and without ICM, and between patients with an eGFR＜60 ml?min-1?1.73m-2 and those with an eGFR ≥60 ml?min-1?1.73m-2. Results There were no significant differences in plasma hemoglobin concentration and eGFR between ICM and non-ICM group (118.49 ± 20.52 g?L-1 vs. 115.80 ± 23.32 g?L-1 and 75.13 ± 24.21 ml?min-1?1.73m-2 vs. 79.09 ± 28.41 ml?min-1?1.73m-2, respectively, both P＞0.05). However, in both ICM and non-ICM groups, plasma hemoglobin concentration was lower in those with an eGFR<60 ml?min-1?1.73m-2 compared with compared with those with an eGFR≥60 ml?min-1?1.73m-2 group (112.29 ± 18.61 g?L-1 vs. 119.92 ± 20.74L-1, P<0.05); plasma hemoglobin concentration was related positively to eGFR. Conclusions There were no significant changes in plasma hemoglobin concentration and eGFR; however, plasma hemoglobin concentration was related to eGFR significantly positively in elderly patients with ICM due to coronary heart disease.
Objectives To study the relationship between plasma hemoglobin concentration and estimated glomerular filtration rate (eGFR) in elderly patients with ischemic cardiomyopathy (ICM). Methods Clinical data of patients with coronary heart disease who were discharged from The First Affiliated Hospital, Chongqing Medical University between 2005 and 2007 were analyzed retrospectively. Echocardiography results, plasma hemoglobin and creatinine concentration were abstracted from the medical records. The study included 235 Chinese Han patients with age 60 years and older with angiography confirmed coronary heart disease, silent myocardial ischemia or angina pectoris, of whom 154 had ICM defined as left ventricular end-diastolic diameter (LVDd), male≥56 mm, female ≥51 mm (63.51±7.70 mm) measured by M-mode echocardiography. The differences in plasma hemoglobin concentration were analyzed retrospectively between patients with and without ICM, and between patients with an eGFR＜60 ml?min-1?1.73m-2 and those with an eGFR ≥60 ml?min-1?1.73m-2. Results There were no significant differences in plasma hemoglobin concentration and eGFR between ICM and non-ICM group (118.49 ± 20.52 g?L-1 vs. 115.80 ± 23.32 g?L-1 and 75.13 ± 24.21 ml?min-1?1.73m-2 vs. 79.09 ± 28.41 ml?min-1?1.73m-2, respectively, both P＞0.05). However, in both ICM and non-ICM groups, plasma hemoglobin concentration was lower in those with an eGFR<60 ml?min-1?1.73m-2 compared with compared with those with an eGFR≥60 ml?min-1?1.73m-2 group (112.29 ± 18.61 g?L-1 vs. 119.92 ± 20.74L-1, P<0.05); plasma hemoglobin concentration was related positively to eGFR. Conclusions There were no significant changes in plasma hemoglobin concentration and eGFR; however, plasma hemoglobin concentration was related to eGFR significantly positively in elderly patients with ICM due to coronary heart disease.
2008, 5(3): 155-158.
Abstract:
Objective To investigate the effects of puerarin (Pur) on myocardial perfusion and ventricular wall motion in patients with acute coronary syndrome (ACS). Methods Thirty-seven patients with ACS were randomly divided into two groups: conventional treatment group (n=17, 11 males, range of age: 32-80 years, average age: 60.9±4.9 years) and Pur treatment group (n=20,12 males, range of age: 40-76 years, average age: 62.7±3.5 years). Patients in the conventional treatment group received standard treatment according to the current guidelines, while patients in the Pur treatment group received intravenous administration of Pur (500 mg/day) for 10 days plus conventional treatment. Real-time myocardial contrast echocardiography (RT-MCE ) was performed to evaluate the change in myocardial perfusion index (MPI) and ventricular wall motion index (VWMI) at admission and 10 days after treatment. Results At 10 days after treatment, MPI was significantly higher (P<0.01) and VWMI significantly lower (P<0.01) in the Pur group comparing with those in the conventional group. Conclusions Puerarin might improve myocardial microcirculation perfusion and ventricular wall motion in patients with ACS.
Objective To investigate the effects of puerarin (Pur) on myocardial perfusion and ventricular wall motion in patients with acute coronary syndrome (ACS). Methods Thirty-seven patients with ACS were randomly divided into two groups: conventional treatment group (n=17, 11 males, range of age: 32-80 years, average age: 60.9±4.9 years) and Pur treatment group (n=20,12 males, range of age: 40-76 years, average age: 62.7±3.5 years). Patients in the conventional treatment group received standard treatment according to the current guidelines, while patients in the Pur treatment group received intravenous administration of Pur (500 mg/day) for 10 days plus conventional treatment. Real-time myocardial contrast echocardiography (RT-MCE ) was performed to evaluate the change in myocardial perfusion index (MPI) and ventricular wall motion index (VWMI) at admission and 10 days after treatment. Results At 10 days after treatment, MPI was significantly higher (P<0.01) and VWMI significantly lower (P<0.01) in the Pur group comparing with those in the conventional group. Conclusions Puerarin might improve myocardial microcirculation perfusion and ventricular wall motion in patients with ACS.
2008, 5(3): 159-163.
Abstract:
Background Atrial electrical remodeling(AER) plays an important role in the pathogenesis and maintenance of atrial fibrillation. However, little is known about modulation of vagal activity to AER. This study aimed to investigate the relationship between vagal moduation and AER. Methods Twenty four adult mongrel dogs under general anesthesia were randomized into 3 groups. Sympathetic activity was blocked by administration of metoprolol in 3 groups. The changes in vagal modulation to atria after AER were observed in 10 dogs without vagal interruption in group A. The effects of vagal intervention on AER were investigated in 8 dogs with administration of atropine in group B. The impact of aggressively vagal activity on AER was studied in 6 dogs with bilateral cervical vag sympathetic trunks stimulation during AER in group C. Bilateral cervical vagosympathetic trunks were decentralized. Multipolar catheters were placed into high right atria (RA), coronary sinus (CS) and right ventricle (RV). AER was induced by 600 bpm pacing through RAcatheter for 30 minutes. Atrial effective refractory period (ERP) and vulnerability window (VW) of atrial fibrillation were measured with and without vagal stimulation before and after AER. Results In group A, ERP decreased significantly at baseline and during vagal stimulation after AER compared with that before AER (all P 0.05). In group C, ERP shortened significantly at baseline and vagal stimulation after AER compared with that before AER (all P <0.05). ERP shortening after AER in Groups A and C increased significantly than that in group B (all P <0.05). Atrial fibrillation could not be induced at baseline (VWclose to 0) before and after AER in three groups. VWbecame widen significantly during vagal stimulation after AER compared with that before AER in Groups Aand C (all P<0.05), while VWremained unchanged in group B (VWclose to 0). Conclusions Short-termAER results in the decrease in ERP. AER is accompanied by the increases in atrial vagal modulation. The increased vagal activity and vagal stimulation promote AER, thereby increase the susceptibility to atrial fibrillation. The interrupted vagal activity attenuates AER, thereby suppresses the atrial fibrillation mediated by vagal stimulation.
Background Atrial electrical remodeling(AER) plays an important role in the pathogenesis and maintenance of atrial fibrillation. However, little is known about modulation of vagal activity to AER. This study aimed to investigate the relationship between vagal moduation and AER. Methods Twenty four adult mongrel dogs under general anesthesia were randomized into 3 groups. Sympathetic activity was blocked by administration of metoprolol in 3 groups. The changes in vagal modulation to atria after AER were observed in 10 dogs without vagal interruption in group A. The effects of vagal intervention on AER were investigated in 8 dogs with administration of atropine in group B. The impact of aggressively vagal activity on AER was studied in 6 dogs with bilateral cervical vag sympathetic trunks stimulation during AER in group C. Bilateral cervical vagosympathetic trunks were decentralized. Multipolar catheters were placed into high right atria (RA), coronary sinus (CS) and right ventricle (RV). AER was induced by 600 bpm pacing through RAcatheter for 30 minutes. Atrial effective refractory period (ERP) and vulnerability window (VW) of atrial fibrillation were measured with and without vagal stimulation before and after AER. Results In group A, ERP decreased significantly at baseline and during vagal stimulation after AER compared with that before AER (all P 0.05). In group C, ERP shortened significantly at baseline and vagal stimulation after AER compared with that before AER (all P <0.05). ERP shortening after AER in Groups A and C increased significantly than that in group B (all P <0.05). Atrial fibrillation could not be induced at baseline (VWclose to 0) before and after AER in three groups. VWbecame widen significantly during vagal stimulation after AER compared with that before AER in Groups Aand C (all P<0.05), while VWremained unchanged in group B (VWclose to 0). Conclusions Short-termAER results in the decrease in ERP. AER is accompanied by the increases in atrial vagal modulation. The increased vagal activity and vagal stimulation promote AER, thereby increase the susceptibility to atrial fibrillation. The interrupted vagal activity attenuates AER, thereby suppresses the atrial fibrillation mediated by vagal stimulation.
2008, 5(3): 164-168.
Abstract:
Background and Objective Increased transmural dispersion of repolarization (TDR) has been shown to contribute to initiation and maintenance of ventricular arrhythmia in long QT syndromes (LQTS). Intercellular uncoupling through gap junctions is an important mechanism for maintaining TDR in both intact and diseased heart. The present study was to test the hypothesis that improving gap junction communication reduces TDR and prevents ventricular arrhythmia in rabbit LQT2 model. Methods An arterially perfused rabbit left ventricular preparation and E-4031 (0.5μmol/L) were used to establish a model of LQT2. Preparations were randomly assigned to control (n=10), AAP-100nmol/L(n=10), AAP-500nM(n=10) groups. Transmural ECG as well as action potentials from both endocardium and epicardium was simultaneously recorded. Results In LQT2 model, presence of 500nmol/L AAP10 reduced endocardial action potential andTDR and prevented ventricular arrhythmia comparing with the control andAAP100nmol/L groups (P < 0.05). Conclusions The presence of 500 nmol/L AAP10 reduces TDR and prevents ventricular arrhythmia in rabbit ventricular model of LQT2. This study suggests a possible role of GJs in TDR in rabbit LQT2 model and indicates a new clinical approach to the management of LQTS.
Background and Objective Increased transmural dispersion of repolarization (TDR) has been shown to contribute to initiation and maintenance of ventricular arrhythmia in long QT syndromes (LQTS). Intercellular uncoupling through gap junctions is an important mechanism for maintaining TDR in both intact and diseased heart. The present study was to test the hypothesis that improving gap junction communication reduces TDR and prevents ventricular arrhythmia in rabbit LQT2 model. Methods An arterially perfused rabbit left ventricular preparation and E-4031 (0.5μmol/L) were used to establish a model of LQT2. Preparations were randomly assigned to control (n=10), AAP-100nmol/L(n=10), AAP-500nM(n=10) groups. Transmural ECG as well as action potentials from both endocardium and epicardium was simultaneously recorded. Results In LQT2 model, presence of 500nmol/L AAP10 reduced endocardial action potential andTDR and prevented ventricular arrhythmia comparing with the control andAAP100nmol/L groups (P < 0.05). Conclusions The presence of 500 nmol/L AAP10 reduces TDR and prevents ventricular arrhythmia in rabbit ventricular model of LQT2. This study suggests a possible role of GJs in TDR in rabbit LQT2 model and indicates a new clinical approach to the management of LQTS.
2008, 5(3): 169-174.
Abstract:
Objective To determine whether Ca2+ activated Cl- current (ICl(Ca)) contributes to the functional remodeling of the failing heart. Methods Whole cell patch-clamp recording technique was employed to record the ICl(Ca) in cardiac myocytes enzymatically isolated from rapidly pacing induced canine failing hearts at room temperature and compared that of the normal hearts (Nor). Results The current density of DIDS (200M) sensitive ICl(Ca) induced by intracellular Ca2+ release trigged by L-type Ca2+ current (ICa,L) was significantly decreased in heart failare (HF) cells compared to Nor cells. At membrane voltage of 20mV, the ICl(Ca) density was 3.02±0.54 pA/pF in Nor (n=6) vs. 1.31±0.25 pA/pF in HF (n=8) cells, (P<0.01), while the averaged ICa,L density did not show difference between two groups. The time constant of current decay of ICl(Ca) was similar in both types of cells. On the other hand, in intra cellular Ca2+ clamped mode, where the [Ca2+]i was maintained at 100nmol/L, ICl(Ca) density be increased significantly in HF cells when the membrane voltage at +30mV or higher. Conclusions Our results suggest that ICl(Ca) density was decreased in pacing induced failing heart but the channel function be enhanced. Impaired Ca2+ handing in HF cells rather than reduced ICl(Ca) channel function itself may have caused this abnormality. The ICl(Ca) density reduction might contribute to the prolongation of action potential in failing heart. The ICl(Ca) channel function up-rugulation is likely to cause cardiac arrhythmia by inducing a delayed after depolarization, when Ca2+ overload occurred in diastolic failing heart cells.
Objective To determine whether Ca2+ activated Cl- current (ICl(Ca)) contributes to the functional remodeling of the failing heart. Methods Whole cell patch-clamp recording technique was employed to record the ICl(Ca) in cardiac myocytes enzymatically isolated from rapidly pacing induced canine failing hearts at room temperature and compared that of the normal hearts (Nor). Results The current density of DIDS (200M) sensitive ICl(Ca) induced by intracellular Ca2+ release trigged by L-type Ca2+ current (ICa,L) was significantly decreased in heart failare (HF) cells compared to Nor cells. At membrane voltage of 20mV, the ICl(Ca) density was 3.02±0.54 pA/pF in Nor (n=6) vs. 1.31±0.25 pA/pF in HF (n=8) cells, (P<0.01), while the averaged ICa,L density did not show difference between two groups. The time constant of current decay of ICl(Ca) was similar in both types of cells. On the other hand, in intra cellular Ca2+ clamped mode, where the [Ca2+]i was maintained at 100nmol/L, ICl(Ca) density be increased significantly in HF cells when the membrane voltage at +30mV or higher. Conclusions Our results suggest that ICl(Ca) density was decreased in pacing induced failing heart but the channel function be enhanced. Impaired Ca2+ handing in HF cells rather than reduced ICl(Ca) channel function itself may have caused this abnormality. The ICl(Ca) density reduction might contribute to the prolongation of action potential in failing heart. The ICl(Ca) channel function up-rugulation is likely to cause cardiac arrhythmia by inducing a delayed after depolarization, when Ca2+ overload occurred in diastolic failing heart cells.
2008, 5(3): 175-178.
Abstract:
Objective To investigate the effects of ciyclosporine-A (CsA), a calcineurin (CaN) inhibitor, on electrophysiological properties of atria in canine tachycardia-induced model of AF. Methods Eighteen healthy adult mongrel canines weighing 17.0 to 23.2 kg(ranged from 2 to 4 years old)were randomized to 3 groups, Sham group (no pacemaker was implanted), atrial tachypacing group (ATP group) and CsA group (atrial tachypacing plus oral administration of CsA 10 mg?kg-1?d-1). Electrophysiological tests were performed on each group at baseline and after 8 weeks’ tachypacing. Measurements included atrial effective refractory period(AERP), conduction velocity (CV), wave length (WL), atrial fibrillation load and rate-adaptability. Results After 8 weeks’ atrial tachypacing, ATP and CsA groups showed significant longer duration of the P wave, shorter AERP, decreased adaptation of AERP, slower CV, shorter WL and longer AF duration compared to the sham group (all P<0.05). AERP of the CsAgroup was longer than that of ATP group (P<0.05), but there were no differences in rate-adaptability, CV, incidence of induced AF and AF duration between CsA group and ATP group. Conclusions Our results suggest that calcineurin pathway intervention by CsA have a positive effect on tachycardia-induced electrical remodeling of atria, but can not prevent or reverse AF.
Objective To investigate the effects of ciyclosporine-A (CsA), a calcineurin (CaN) inhibitor, on electrophysiological properties of atria in canine tachycardia-induced model of AF. Methods Eighteen healthy adult mongrel canines weighing 17.0 to 23.2 kg(ranged from 2 to 4 years old)were randomized to 3 groups, Sham group (no pacemaker was implanted), atrial tachypacing group (ATP group) and CsA group (atrial tachypacing plus oral administration of CsA 10 mg?kg-1?d-1). Electrophysiological tests were performed on each group at baseline and after 8 weeks’ tachypacing. Measurements included atrial effective refractory period(AERP), conduction velocity (CV), wave length (WL), atrial fibrillation load and rate-adaptability. Results After 8 weeks’ atrial tachypacing, ATP and CsA groups showed significant longer duration of the P wave, shorter AERP, decreased adaptation of AERP, slower CV, shorter WL and longer AF duration compared to the sham group (all P<0.05). AERP of the CsAgroup was longer than that of ATP group (P<0.05), but there were no differences in rate-adaptability, CV, incidence of induced AF and AF duration between CsA group and ATP group. Conclusions Our results suggest that calcineurin pathway intervention by CsA have a positive effect on tachycardia-induced electrical remodeling of atria, but can not prevent or reverse AF.
2008, 5(3): 179-181.
Abstract:
Objective To investigate the effects of simvastatin on membrane ionic currents in left ventricular myocytes after acute myocardial infarction (AMI, so as to explore the ionic mechanism of statin treatment for antiarrhythmia. Methods Fourty-five New Zeland rabbits were randomly divided into three groups: AMI group, simvastatin intervention group (statin group) and sham-operated control group (CON). Rabbits were infarcted by ligation of the left anterior descending coronary artery after administration of oral simvastatin 5 mg?kg-1?d-1 (Statin group) or placebo (AMI group)for 3 days. Twenty-four hours later, single ventricular myocytes were isolated enzymatically from the epicardial zone of the infracted region. Whole cell patch clamp technique was used to record membrane ionic currents, including sodium current (INa), L-type calcium current (ICa-L) and transient outward potassium current (Ito). Results ① There was no significant difference in serum cholesterol concentration among three groups. ② The peak INa current density (at –30 mV) was significantly decreased in AMI group (–23.26±5.18) compared with CON (–42.78±5.48, P<0.05), while it was significantly increased in Statin group (–39.23±5.45) compared with AMI group (P<0.01); The peak ICa-L current density (at 0 mV) was significantly decreased in AMI group (–3.23±0.91) compared with CON (–4.56±1.01,P<0.05), while it was significantly increased in Statin group (–4.18±0.95) compared with AMI group (P<0.05); The Ito current density(at +60 mV) was significantly decreased in AMI group(10.41±1.93)compared with CON (17.41± 3.13, P<0.01), while it was significantly increased in Statin group(16.21 ± 2.42)compared with AMI group (P<0.01). Conclusions AMI induces significant down-regulation of INa, ICa-L and Ito. Pretreatment with simvastatin could attenuate this change without lowering the serum cholesterol level, suggesting that simvastatin reverse this electrical remodeling, thus contributing to the ionic mechanism of statin treatment for antiarrhythmia.
Objective To investigate the effects of simvastatin on membrane ionic currents in left ventricular myocytes after acute myocardial infarction (AMI, so as to explore the ionic mechanism of statin treatment for antiarrhythmia. Methods Fourty-five New Zeland rabbits were randomly divided into three groups: AMI group, simvastatin intervention group (statin group) and sham-operated control group (CON). Rabbits were infarcted by ligation of the left anterior descending coronary artery after administration of oral simvastatin 5 mg?kg-1?d-1 (Statin group) or placebo (AMI group)for 3 days. Twenty-four hours later, single ventricular myocytes were isolated enzymatically from the epicardial zone of the infracted region. Whole cell patch clamp technique was used to record membrane ionic currents, including sodium current (INa), L-type calcium current (ICa-L) and transient outward potassium current (Ito). Results ① There was no significant difference in serum cholesterol concentration among three groups. ② The peak INa current density (at –30 mV) was significantly decreased in AMI group (–23.26±5.18) compared with CON (–42.78±5.48, P<0.05), while it was significantly increased in Statin group (–39.23±5.45) compared with AMI group (P<0.01); The peak ICa-L current density (at 0 mV) was significantly decreased in AMI group (–3.23±0.91) compared with CON (–4.56±1.01,P<0.05), while it was significantly increased in Statin group (–4.18±0.95) compared with AMI group (P<0.05); The Ito current density(at +60 mV) was significantly decreased in AMI group(10.41±1.93)compared with CON (17.41± 3.13, P<0.01), while it was significantly increased in Statin group(16.21 ± 2.42)compared with AMI group (P<0.01). Conclusions AMI induces significant down-regulation of INa, ICa-L and Ito. Pretreatment with simvastatin could attenuate this change without lowering the serum cholesterol level, suggesting that simvastatin reverse this electrical remodeling, thus contributing to the ionic mechanism of statin treatment for antiarrhythmia.
2008, 5(3): 182-185.
Abstract:
Objective To investigate the preventive effect of magnetic stent on coronary restenosis after percutaneous arterial stenting. Methods Twenty rabbits were divided randomly into 2 groups. Bare stent (BS group, n=10) or magnetic stent (MS group, n=10) was implanted in the left iliac artery of the rabbits of the 2 groups, respectively. Aspirin (25mg, qd) was administered orally to the rabbits of both groups from 3 days before stenting until the rabbits were executed. Unfractionated heparin (2500u, qd) was delivered subcutaneously after stenting for 7 days. Five rabbits of each group were randomly selected to be executed at 7 or 30 days. Structural changes in the injured arteries were studied by optical microscopey, transmissive electronic microscopey and immunohistochemistry. Results At 7 days, more myofibroblasts were found migrating from adventitia to tunica media and intima in BS group than in MS group. Inside the media and intima, large amount of smooth muscle cells of synthetic type were observed. At 30 days after stenting, in magnetic group, most uascular smooth muscle cells (SMCs) under the intima had transformed to contractile type and only little extracellular matrix (ECM) was observed around the SMCs; whereas, in BS group, the SMCs remained to be synthetic type and large amount of ECM was observed around the SMCs, which was composed mainly of proteoglycans and glycoproteins. Conclusions Magnetic stent can inhibit proliferation and migration of SMCs and reducing the production of ECM, and therefore, may prevent restenosis after coronary stenting.
Objective To investigate the preventive effect of magnetic stent on coronary restenosis after percutaneous arterial stenting. Methods Twenty rabbits were divided randomly into 2 groups. Bare stent (BS group, n=10) or magnetic stent (MS group, n=10) was implanted in the left iliac artery of the rabbits of the 2 groups, respectively. Aspirin (25mg, qd) was administered orally to the rabbits of both groups from 3 days before stenting until the rabbits were executed. Unfractionated heparin (2500u, qd) was delivered subcutaneously after stenting for 7 days. Five rabbits of each group were randomly selected to be executed at 7 or 30 days. Structural changes in the injured arteries were studied by optical microscopey, transmissive electronic microscopey and immunohistochemistry. Results At 7 days, more myofibroblasts were found migrating from adventitia to tunica media and intima in BS group than in MS group. Inside the media and intima, large amount of smooth muscle cells of synthetic type were observed. At 30 days after stenting, in magnetic group, most uascular smooth muscle cells (SMCs) under the intima had transformed to contractile type and only little extracellular matrix (ECM) was observed around the SMCs; whereas, in BS group, the SMCs remained to be synthetic type and large amount of ECM was observed around the SMCs, which was composed mainly of proteoglycans and glycoproteins. Conclusions Magnetic stent can inhibit proliferation and migration of SMCs and reducing the production of ECM, and therefore, may prevent restenosis after coronary stenting.
2008, 5(3): 186-189.
Abstract:
A 69-year old female patient was admitted because of 3 days of worsened chest pain. Coronary angiography showed 60% stenosis of distal left main stem, chronic total occlusion of left anterior descending (LAD), 70% stenosis at the ostium of a small left circumflex, 70-90% stenosis at the paroxysmal and middle part of a dominant right coronary artery (RCA), and a normal left internal mammary artery (LIMA) with normal origination and orientation. Percutaneous intervention was attempted but failed on the occluded lesion of LAD. The patient received minimally invasive direct coronary artery bypass (MIDCAB) with left LIMA isolation by Davinci robot. Eleven days later, the RCA lesion was treated by Sirolimus Rapamicin eluting stents implantation percutaneously. Then the patient was discharged uneventfully after 3 days hospitalization. Our experience suggests that two stop shops of hybrid technique be feasible and safe in the treatment of elderly patient with multiple coronary diseases.
A 69-year old female patient was admitted because of 3 days of worsened chest pain. Coronary angiography showed 60% stenosis of distal left main stem, chronic total occlusion of left anterior descending (LAD), 70% stenosis at the ostium of a small left circumflex, 70-90% stenosis at the paroxysmal and middle part of a dominant right coronary artery (RCA), and a normal left internal mammary artery (LIMA) with normal origination and orientation. Percutaneous intervention was attempted but failed on the occluded lesion of LAD. The patient received minimally invasive direct coronary artery bypass (MIDCAB) with left LIMA isolation by Davinci robot. Eleven days later, the RCA lesion was treated by Sirolimus Rapamicin eluting stents implantation percutaneously. Then the patient was discharged uneventfully after 3 days hospitalization. Our experience suggests that two stop shops of hybrid technique be feasible and safe in the treatment of elderly patient with multiple coronary diseases.
2008, 5(3): 190-192.
Abstract:
Mid-ventricular hypertrophic obstructive cardiomyopathy (MVHOCM) is a rare type of cardiomyopathy that can be accompanied by apical aneurysm. We presented here a case report of MVHOCM with cornary artery disease. The sixty-four years old man was sent to hospital because of ventricular tachycardia. Large inversion T wave was showed on electrocardiography in the presence of abnormal coronary arteries and normal cardiac enzyme. Echocardiography showed an hourglass appearance of the left ventricle with an aneurysm in the apex and a pressure gradient between the outflow tract of left ventricle and the middle of the left ventricle was revealed by left-heart catheterization.
Mid-ventricular hypertrophic obstructive cardiomyopathy (MVHOCM) is a rare type of cardiomyopathy that can be accompanied by apical aneurysm. We presented here a case report of MVHOCM with cornary artery disease. The sixty-four years old man was sent to hospital because of ventricular tachycardia. Large inversion T wave was showed on electrocardiography in the presence of abnormal coronary arteries and normal cardiac enzyme. Echocardiography showed an hourglass appearance of the left ventricle with an aneurysm in the apex and a pressure gradient between the outflow tract of left ventricle and the middle of the left ventricle was revealed by left-heart catheterization.
