OBJECTIVE: To investigate the effects of interval training on calcium transient and contractile function in ischemic ventricular myocytes of rats with myocardial infarction and their synchronization. METHODS: Twenty-four male sprague-dawley rats in three years old, were randomly divided into three groups (n=8): sham-operated group(S), sedentary MI group(MI) and MI with interval training group (ME). The MI model was established by ligation of the left anterior descending coronary artery. The rats in ME group started training 1 week after MI operation. The S model was established by threading only without ligation. ME model took one week adaptive training, 10 m/min and 30 min/d, then took subsequently 8-week aerobic interval training: 10 min×10 m/min, then reran the rats with 2 intensities 15 m/min×6 min and 25 m/min×4 min, 1 h/d, 5 d/week. After training 24 hours, the cardiomyocytes of all groups were isolated by using the Langendorff fusion system. The contractile function and calcium transient of single ventricular myocyte in myocardial infarction adult rats were detected by IonOptix. Calcium transients were measured as [Ca] amplitude, departure velocity, ratio, TTB50％, TTP and TTP50%, return velocity and ratio amplitude. PTA, SL, ±dl/dtmax and SL shortening% were tested to evaluate contractility. RESULTS: Compared with S, the levels of [Ca] amplitude, departure velocity, ratio amplitude and return velocity, SL shortening%, PTA and ±dl/dtmax of MI were decreased(P＜0.01), the levels of TTP, TTP50% and TTB50% of MI were increased(P＜0.01); Compared with MI, the levels of departure velocity, ratio amplitude, return velocity and [Ca] amplitude of ME were increased(P＜0.01), the levels of TTB50%, TTP and TTP50% of ME were decreased(P＜0.01, P＜0.05). The levels of SL shortening%, PTA and ±dl/dtmax of ME were increased(P＜0.01, P＜0.05). CONCLUSION Interval training can improve calcium transient and contractile function of single ventricular myocyte in myocardial infarction adult rats.
Animals ; Calcium ; physiology ; Male ; Myocardial Contraction ; Myocardial Infarction ; pathology ; Myocytes, Cardiac ; physiology ; Physical Conditioning, Animal ; Random Allocation ; Rats ; Rats, Sprague-Dawley

OBJECTIVE: To assess magnetic resonance imaging (MRI) features of coronary microembolization in a swine model induced by small-sized microemboli, which may cause microinfarcts invisible to the naked eye. MATERIALS AND METHODS: Eleven pigs underwent intracoronary injection of small-sized microspheres (42 microm) and catheter coronary angiography was obtained before and after microembolization. Cardiac MRI and measurement of cardiac troponin T (cTnT) were performed at baseline, 6 hours, and 1 week after microembolization. Postmortem evaluation was performed after completion of the imaging studies. RESULTS: Coronary angiography pre- and post-microembolization revealed normal epicardial coronary arteries. Systolic wall thickening of the microembolized regions decreased significantly from 42.6 +/- 2.0% at baseline to 20.3 +/- 2.3% at 6 hours and 31.5 +/- 2.1% at 1 week after coronary microembolization (p < 0.001 for both). First-pass perfusion defect was visualized at 6 hours but the extent was largely decreased at 1 week. Delayed contrast enhancement MRI (DE-MRI) demonstrated hyperenhancement within the target area at 6 hours but not at 1 week. The microinfarcts on gross specimen stained with nitrobluetetrazolium chloride were invisible to the naked eye and only detectable microscopically. Increased cTnT was observed at 6 hours and 1 week after microembolization. CONCLUSION: Coronary microembolization induced by a certain load of small-sized microemboli may result in microinfarcts invisible to the naked eye with normal epicardial coronary arteries. MRI features of myocardial impairment secondary to such microembolization include the decline in left ventricular function and myocardial perfusion at cine and first-pass perfusion imaging, and transient hyperenhancement at DE-MRI.
Animals ; Coronary Angiography/*methods ; Coronary Vessels/*pathology ; Disease Models, Animal ; Embolism/*pathology ; Female ; Heart/radiography ; Image Processing, Computer-Assisted ; Magnetic Resonance Imaging/*methods ; Microspheres ; Myocardial Contraction/physiology ; Myocardial Infarction/*pathology ; Myocardium/pathology ; Nitroblue Tetrazolium ; Staining and Labeling ; Swine ; Troponin T/blood ; Ventricular Function, Left

Cardiac resynchronization therapy (CRT) has been shown to reduce the risk of death and hospitalization in patients with advanced heart failure with left ventricular dysfunction. However, controversy remains regarding who would most benefit from CRT. We performed a meta-analysis, and meta-regression in an attempt to identify factors that determine the outcome after CRT. A total of 23 trials comprising 10,103 patients were selected for this meta-analysis. Our analysis revealed that CRT significantly reduced the risk of all-cause mortality and hospitalization for heart failure compared to control treatment. The odds ratio (OR) of all-cause death had a linear relationship with mean QRS duration (P=0.009). The benefit in survival was confined to patients with a QRS duration > or =145 ms (OR, 0.86; 95% CI, 0.74-0.99), while no benefit was shown among patients with a QRS duration of 130 ms (OR, 1.00; 95% CI, 0.80-1.25) or less. Hospitalization for heart failure was shown to be significantly reduced in patients with a QRS duration > or =127 ms (OR, 0.77; 95% CI, 0.60-0.98). This meta-regression analysis implies that patients with a QRS duration > or =150 ms would most benefit from CRT, and in those with a QRS duration <130 ms CRT implantation may be potentially harmful.
Bundle-Branch Block/physiopathology ; Cardiac Resynchronization Therapy/*methods ; Cardiac Resynchronization Therapy Devices ; Defibrillators, Implantable ; Electrocardiography ; Heart Failure/mortality/physiopathology/*therapy ; Humans ; Myocardial Contraction/*physiology ; Treatment Outcome ; Ventricular Dysfunction, Left/mortality/physiopathology/*therapy

To discuss the protective effect of aralosides (AS) on I/R-induced rat myocardial injury. The adult rat ventricular myocyte ischemia model was established through perfusion with sodium lactate perfusate and reperfusion with Ca(2+) -containing Tyrode's solution simulation. The cell contraction and ion concentration synchronization determination system was applied to detect the effect of AS on single I/R cell contraction and Ca2+ transients. According to the findings, AS could increase resting sarcomere length, contraction amplitude, ± dL/dt(max), calcium transient amplitude and speed of post-reperfusion myocardial cells (P < 0.05, P < 0.01), and decrease in time for achieving 90.0% of maximum relaxation, time for achieving peak value, resting calcium ratio, contraction period [Ca2+] i, time for achieving 50.0% of maximum relaxation and attenuation rate of intracellular calcium transient (P < 0.05, P < 0.01). Therefore, it is suggested that AS improved the post-reperfusion cell contraction and injury of calcium homeostasis.
Animals ; Aralia ; chemistry ; Biological Transport ; drug effects ; Calcium ; metabolism ; Drugs, Chinese Herbal ; administration & dosage ; Humans ; Male ; Muscle Contraction ; drug effects ; Myocardial Ischemia ; drug therapy ; metabolism ; physiopathology ; surgery ; Myocardial Reperfusion ; Myocytes, Cardiac ; drug effects ; physiology ; Rats ; Rats, Sprague-Dawley ; Saponins ; administration & dosage

OBJECTIVE: To investigate the pathological features and significance of myocardial contraction band necrosis in sudden cardiac death. METHODS: Using HE and PTAH staining, the distribution sites and pathological features of myocardial contraction band necrosis were observed. The data were analyzed according to the extent of necrosis. RESULTS: The locations, pathological features and the extent of necrosis were similar in different sudden death cases. The locations were related with sites of myocardial damage. The papillary muscles of left ventricular were most occurred, followed by the anterior wall of left ventricular. In the sudden death cases caused by stress cardiomyopathy, the extent of myocardial contraction band necrosis was lighter than the others. Most cases were predominantly level 1, the others were level 2. CONCLUSION Used as the diagnosis basis of acute myocardial ischemia, the myocardial contraction band necrosis has important significance to determination of death.
Adult ; Aged ; Aged, 80 and over ; Coronary Disease/complications* ; Death, Sudden/etiology* ; Death, Sudden, Cardiac/pathology* ; Female ; Heart Diseases/pathology* ; Humans ; Male ; Middle Aged ; Myocardial Contraction/physiology* ; Myocardium/pathology* ; Necrosis

This study examined the effect of cholic acid (CA) on cultured cardiac myocytes (CMs) from neonatal rats with an attempt to explore the possible mechanism of sudden fetal death in intrahepatic cholestasis of pregnancy (ICP). Inverted microscopy was performed to detect the impact of CA on the beating rates of rat CMs. MTT method was used to study the effect of CA on the viability of CMs. CMs cultured in vitro were incubated with 10 μmol/L Ca(2+)-sensitive fluorescence indicator fluo-3/AM. The fluorescence signals of free calcium induced by CA were measured under a laser scanning confocal microscope. The results showed that CA decreased the beating rates of the CMs in a dose-dependent manner. CA could suppress the activities of CMs in a time- and dose-dependent manner. CA increased the concentration of intracellular free calcium in a dose-dependent manner. Our study suggested that CA could inhibit the activity of CMs by causing calcium overload, thereby leading to the sudden fetal death in ICP.
Animals ; Animals, Newborn ; Calcium ; metabolism ; Cells, Cultured ; Cholestasis, Intrahepatic ; complications ; metabolism ; physiopathology ; Cholic Acid ; metabolism ; pharmacology ; Death, Sudden ; etiology ; Dose-Response Relationship, Drug ; Female ; Fetal Death ; etiology ; Humans ; Microscopy, Confocal ; Myocardial Contraction ; drug effects ; Myocytes, Cardiac ; drug effects ; metabolism ; physiology ; Pregnancy ; Pregnancy Complications ; metabolism ; physiopathology ; Rats, Sprague-Dawley ; Time Factors

The purpose of this study was to determine the combined effect of transmyocardial laser revascularization (TMLR) and the implantation of endothelial progenitor cells (EPCs) on cardiac function of ischemic hearts in canines. The left anterior descending artery (LAD) was occluded to establish the canine model of acute myocardial infarct (AMI). Four weeks later, the animals were randomly divided into four groups: TMLR group, in which transmyocardial laser-induced channels were established at the ischemic region; EPCs+TMLR group, in which EPCs were locally transplanted into laser-induced channels at the ischemic region; EPCs group, in which the EPCs were injected into the ischemic region; control group, in which the AMI animals received neither TMLR nor EPCs. The peripheral blood (50 mL) was sampled in all groups. Mononuclear cells from the peripheral blood were separated and cultured to obtain spindle-shaped attaching (AT) cells in vitro. AT cells were labeled with 1, 1'-dioctadecyl-1 to 3,3, 3',3'-tetramethyl-indocarbocyanine perchlorate (DiI) before injecting into the laser-induced channels or ischemic region. Four weeks after the first operation, TMLR was performed in the TMLR group and EPCs+TMLR group, and at the same time, the EPCs originating from the AT cells were mixed with calcium alginate (CA). Then the EPCs-CA composites were implanted into myocardial channels induced by laser in the EPCs+TMLR group, and into the myocardial infarct area in the EPCs group. All dogs underwent echocardiography at second month after LAD occlusion. Finally the samples of myocardium around the LAD were subjected to histochemical and immunohistologic examinations. The results showed there was no significant difference in the diameter of left atrium and ventricle before treatment among all groups (P>0.05). Eight weeks after modeling, the regional contractility in the LAD territory in the EPCs+TMLR group was increased as compared with control group and TMLR group, but there was no significant difference between control group and TMLR group. Neoangiogenesis was observed in the EPCs+TMLR group, and the fibrosis was seen in the TMLR group. There was no significant difference in neoangiogenesis around the channels induced by laser among EPCs+TMLR, EPCs and TMLR groups. It was concluded that TMLR combined with EPCs could improve the regional and global cardiac function in AMI, and augment neovascularizaiton in channels of ischemic myocardium induced by laser.
Animals ; Coronary Circulation ; Coronary Vessels ; pathology ; surgery ; Dogs ; Humans ; Muscle Contraction ; physiology ; Myocardial Ischemia ; pathology ; therapy ; Myocardium ; pathology ; Neovascularization, Physiologic ; physiology ; Stem Cell Transplantation ; methods ; Stem Cells ; Transmyocardial Laser Revascularization ; methods

OBJECTIVE: The aim of this study was to investigate the most robust predictor of myocardial viability among stress/rest reversibility (coronary flow reserve [CFR] impairment), 201Tl perfusion status at rest, 201Tl 24 hours redistribution and systolic wall thickening of 99mTc-methoxyisobutylisonitrile using a dual isotope gated myocardial perfusion single-photon emission computed tomography (SPECT) in patients with coronary artery disease (CAD) who were re-vascularized with a coronary artery bypass graft (CABG) surgery. MATERIALS AND METHODS: A total of 39 patients with CAD was enrolled (34 men and 5 women), aged between 36 and 72 years (mean 58 +/- 8 standard in years) who underwent both pre- and 3 months post-CABG myocardial SPECT. We analyzed 17 myocardial segments per patient. Perfusion status and wall motion were semi-quantitatively evaluated using a 4-point grading system. Viable myocardium was defined as dysfunctional myocardium which showed wall motion improvement after CABG. RESULTS: The left ventricular ejection fraction (LVEF) significantly increased from 37.8 +/- 9.0% to 45.5 +/- 12.3% (p < 0.001) in 22 patients who had a pre-CABG LVEF lower than 50%. Among 590 myocardial segments in the re-vascularized area, 115 showed abnormal wall motion before CABG and 73.9% (85 of 115) had wall motion improvement after CABG. In the univariate analysis (n = 115 segments), stress/rest reversibility (p < 0.001) and 201Tl rest perfusion status (p = 0.024) were significant predictors of wall motion improvement. However, in multiple logistic regression analysis, stress/rest reversibility alone was a significant predictor for post-CABG wall motion improvement (p < 0.001). CONCLUSION: Stress/rest reversibility (impaired CFR) during dual-isotope gated myocardial perfusion SPECT was the single most important predictor of wall motion improvement after CABG.
Adult ; Aged ; Analysis of Variance ; Cardiac-Gated Single-Photon Emission Computer-Assisted Tomography/*methods ; Coronary Artery Bypass ; Coronary Artery Disease/physiopathology/*radionuclide imaging/surgery ; Coronary Circulation/*physiology ; Coronary Disease/radionuclide imaging/surgery ; Female ; Humans ; Male ; Middle Aged ; Myocardial Contraction/physiology ; Myocardium ; Nitriles/diagnostic use ; Stroke Volume/physiology ; Technetium/diagnostic use ; Ventricular Function, Left/physiology

Our study was aimed to evaluate the left ventricular (LV) global longitudinal systolic function of patients with diabetes mellitus (DM) using real-time three-plane speckle tracking imaging (RT-3P STI). The case group was the patients of type 2 DM with normal LV ejection fraction (EF). Then according to glycated hemoglobin (HbAlc) control level, the case group was divided into two groups, including DM1 (HbAlc<7%, n=31) and DM2 (HbAlc >or=7%, n= 37); 63 matched volunteers were chosen as control group. Conventional measurements of the LV size and function were performed. We then applied the automatic function imaging to analyze the global longitudinal systolic peak strain (GLPS) of the three apical views online, including the GLPS of apical four chamber view (GLPS-A4C), the GLPS of apical two chamber view (GLPS-A2C), the GLPS of apical long axis view (GLPS-LAX), and then generating the average GLPS (GLPS-Avg). The experimental results showed that there was no statistical difference in clinical baseline characteristics among the three groups (P>0.05). However, there were statistical differences in the ventricular wall thickness and the LV mass index of the DM1 and DM2 groups compared with that of the control (P<0. 05). No significant differences were found in LV diameters, volumes, LVEF among the three studied groups (P>0. 05). We also found significant differences in GLPS-LAX, GLPS-A2C, GLPS-Avg when we compared DM2 group with those of the DM1 group or the control (P<0. 05). We found a statistical difference in GLPS-A4C only when we compared the DM2 group with the control(P<0. 05), and no statistical difference in the strains of the three views between DM1 group and control (P>0. 05). RT-3P STI could not only accurately be used to evaluate the LV global longitudinal systolic function, but could also reflect the reduction of sub-clilical systolic function in DM patients with poor blood glucose control in the early stage.
Aged ; Case-Control Studies ; Diabetes Mellitus, Type 2 ; complications ; diagnostic imaging ; physiopathology ; Echocardiography, Three-Dimensional ; methods ; Female ; Heart Ventricles ; diagnostic imaging ; Humans ; Male ; Middle Aged ; Myocardial Contraction ; physiology ; Stroke Volume ; Systole ; Ventricular Dysfunction, Left ; diagnostic imaging ; etiology ; Ventricular Function, Left

We sought to explore the feasibility of global area strain to assess left ventricular global systolic function in patients with essential hypertension and normal ventricular geometry. Thirty-five essential hypertensive patients with normal ventricular geometry and 30 normally healthy persons as controls were enrolled in this study. The two groups were comparable for age, sex ratio, height, weight, body mass index (BMI), and heart rate. Blood pressures (BPs) were significantly higher in the hypertension group than the control group. Two-dimensional echocardiography and three-dimensional speckle tracking imaging were performed. Left ventricular global area strain (GAS), global longitudinal strain (GLS), global circumferential strain (GCS), global radial strain (GRS), LV volumes, ejection fraction (EF), sphericity index (SPI), left ventricular end-diastolic and end-systolic mass (EDmass and ESmass) and LV mass index (EDmassI and ESmassI) were obtained. Compared with those of the controls, GAS, GLS, GCS, GRS were significantly reduced in hypertensive patients Call P < 0.001). GAS (r = 0.672, P < 0. 001), GLS (r = 0.587, P < 0.001), GCS (r = 0.639, P < 0.001) and GRS (r = 0.685, P < 0.001) were correlated with EF in the pooled population. GAS showed an excellent correlation with GCS (r = 0.905, P < 0.001), GLS (r = 0.892, P < 0.001) and GRS (r = 0.990, P < 0.001). EF measured with 3D-STI was significantly lower in group of hypertension (P < 0.001) than that in the controls. There were no significant differences between the two groups in cardiac output, sphericity index, EDmass and ESmass, LV mass index (EDmassI and ESmassI) calculated with 3D-STI. The study showed that GAS could identify early changes of left ventricular global systolic function in hypertensive patients with normal ventricular geometry.
Adult ; Aged ; Case-Control Studies ; Echocardiography, Three-Dimensional ; methods ; Female ; Humans ; Hypertension ; diagnostic imaging ; physiopathology ; Male ; Middle Aged ; Myocardial Contraction ; physiology ; Ventricular Function, Left ; physiology ; Young Adult