PURPOSE: Recent evidence suggests that early repolarization (ER) is related with myocardial ischemia. Compression of coronary artery by a myocardial bridging (MB) can be associated with clinical manifestations of myocardial ischemia. This study aimed to evaluate the associations of MB in patients with ER. MATERIALS AND METHODS: In consecutive patients (n=1303, age, 61±12 years) who had undergone coronary angiography, we assessed the prevalence and prognostic implication of MB in those with ER (n=142) and those without ER (n=1161). RESULTS: MB was observed in 54 (38%) and 196 (17%) patients in ER and no-ER groups (p<0.001). In multivariate analysis, MB was independently associated with ER (odd ratio: 2.9, 95% confidence interval: 1.98–4.24, p<0.001). Notched type ER was more frequently observed in MB involving the mid portion of left anterior descending coronary artery (LAD) (69.8% vs. 30.2%, p=0.03). Cardiac event was observed in nine (6.3%) and 22 (1.9%) subjects with and without ER, respectively. MB was more frequently observed in sudden death patients with ER (2 out of 9, 22%) than in those without ER (0 out of 22). CONCLUSION: MB was independently associated with ER in patients without out structural heart disease who underwent coronary angiography. Notched type ER was closely related with MB involving the mid portion of the LAD. Among patients who had experienced cardiac events, a higher prevalence of MB was observed in patients with ER than those without ER. Further prospective studies on the prognosis of MB in ER patients are required.
Aged ; Coronary Angiography ; Electrocardiography ; Electrophysiological Phenomena ; Female ; Humans ; Male ; Middle Aged ; Myocardial Bridging/*complications/*diagnostic imaging/epidemiology/physiopathology ; Myocardial Ischemia/*etiology/physiopathology ; Odds Ratio ; Prevalence ; Prognosis ; Prospective Studies

To explore the protective effects of right coronary artery ischemic preconditioning and post-conditioning on myocardial ischemia reperfusion injury in rabbit heart.
 Methods: A total of 30 rabbits were randomly divided into 4 groups: a control group (n=7), an ischemia reperfusion group (IR group, n=8), an ischemic preconditioning group (IPC group, n=8) and an ischemic post-conditioning group (IPO group, n=7). Venous blood samples were taken at pre-operation, 1 and 6 h post-operation, and the concentration of serum creatine kinase isoenzyme (CK-MB) and cardiac troponin-T (cTn-T) were measured. The infarct area of cardiac muscle was calculated.
 Results: Compared with the IR group, the levels of CK-MB and cTn-T at 1 and 6 h post-operation in the IPC group and the IPO group were reduced (all P<0.05). Compared with the IR group, the infarct size in the IPC group and the IPO group was significantly decreased, with significant difference (both P<0.05) .
 Conclusion: Right coronary artery ischemic preconditioning and post-conditioning exert significant protective effects on the myocardial ischemia reperfusion injury in New Zealand rabbits.
Animals ; Coronary Vessels ; Creatine Kinase, MB Form ; blood ; Heart ; Ischemia ; Ischemic Postconditioning ; Ischemic Preconditioning ; Ischemic Preconditioning, Myocardial ; Myocardial Infarction ; etiology ; pathology ; physiopathology ; prevention & control ; Myocardial Ischemia ; complications ; therapy ; Myocardial Reperfusion Injury ; prevention & control ; Myocardium ; Rabbits ; Troponin T ; blood

To study the therapeutic effect and possible mechanism of icariin on myocardial ischemia-reperfusion injury ( MIRI) model in diabetes rats. The model of diabetic rats were induced by Streptozotocin (STZ), then the model of MIRI was established by ligating the reversible left anterior descending coronary artery for 30 min, and then reperfusing for 120 min. totally 40 male SD were randomly divided into five groups: the control group (NS), the ischemia reperfusion group (NIR), the diabetes control group (MS), the diabetic ischemia reperfusion group (MIR) and the diabetic ischemia reperfusion with icariin group (MIRI). The changes in blood glucose, body weight and living status were observed; the enzyme activity of serum CK-MB, LDH, GSH-Px and myocardium SOD and the content MDA and NO in myocardium were detected; the myocardial pathological changes were observed by HE staining; the myocardial Caspase-3, the Bcl-2, Bax protein expressions were detected by Western blot. The result showed that the diabetes model was successfully replicated; myocardial ischemia-reperfusion injury was more serious in diabetes rats; icariin can increase NO, SOD, GSH-Px, Bcl-2 protein expression, decrease MDA formation, CK-MB and LDH activities and Caspase-3 and Bcl-2 protein expressions and myocardial damage. The result suggested that icariin may play a protective role against ischemia reperfusion myocardial injury in diabetes rats by resisting oxidative stress and inhibiting cell apoptosis.
Animals ; Apoptosis ; drug effects ; Caspase 3 ; metabolism ; Creatine Kinase ; metabolism ; Diabetes Mellitus, Type 2 ; complications ; Drugs, Chinese Herbal ; administration & dosage ; Flavonoids ; administration & dosage ; Humans ; Ischemia ; drug therapy ; etiology ; physiopathology ; Male ; Malondialdehyde ; metabolism ; Myocardial Reperfusion Injury ; drug therapy ; etiology ; metabolism ; physiopathology ; Myocardium ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Rats ; Rats, Sprague-Dawley ; Superoxide Dismutase ; metabolism ; bcl-2-Associated X Protein ; metabolism

Conventional coronary angiography (CAG) has limitations in evaluating lesions producing ischemia. Three dimensional quantitative coronary angiography (3D-QCA) shows reconstructed images of CAG using computer based algorithm, the Cardio-op B system (Paieon Medical, Rosh Ha'ayin, Israel). The aim of this study was to evaluate whether 3D-QCA can reliably predict ischemia assessed by myocardial fractional flow reserve (FFR) < 0.80. 3D-QCA images were reconstructed from CAG which also were evaluated with FFR to assess ischemia. Minimal luminal diameter (MLD), percent diameter stenosis (%DS), minimal luminal area (MLA), and percent area stenosis (%AS) were obtained. The results of 3D-QCA and FFR were compared. A total of 266 patients was enrolled for the present study. FFR for all lesions ranged from 0.57 to 1.00 (0.85 +/- 0.09). Measurement of MLD, %DS, MLA, and %AS all were significantly correlated with FFR (r = 0.569, 0609, 0.569, 0.670, respectively, all P < 0.001). In lesions with MLA < 4.0 mm2, %AS of more than 65.5% had a 80% sensitivity and a 83% specificity to predict FFR < 0.80 (area under curve, AUC was 0.878). 3D-QCA can reliably predict coronary lesions producing ischemia and may be used to guide therapeutic approach for coronary artery disease.
Aged ; Coronary Angiography/*methods ; Coronary Circulation ; Coronary Stenosis/etiology/*physiopathology/*radiography ; Female ; *Fractional Flow Reserve, Myocardial ; Humans ; Imaging, Three-Dimensional/*methods ; Male ; Myocardial Ischemia/complications/physiopathology/*radiography ; Radiographic Image Enhancement/methods ; Radiographic Image Interpretation, Computer-Assisted/methods ; Reproducibility of Results ; Sensitivity and Specificity

OBJECTIVEThe mechanism through which platelet activating factor (PAF) induces cardiac electrical activity and arrhythmia is not well understood and previous studies have suggested a potential involvement of ion channels in its action. The present study was aimed to clarify the role of PAF in fatal arrhythmias following acute myocardia infarction (AMI) and the underlying mechanism.

METHODS(1) Blood PAF levels were measured among 72 AMI patients at the time of diagnosis with AMI and 48 h later, and their electrocardiogram (ECG) was recorded continuously. (2) Ischemia simulation and surface electrocardiogram were conducted in 20 pigs and their PAF levels were measured. (3) PAF perfusion and standard microelectrode recording were performed on guinea pig papillary muscles.

RESULTSIn both humans and pigs, elevated PAF levels were detected in AMI and simulated ischemia, respectively, and even higher PAF levels were found when fatal arrhythmias occurred. In guinea pig myocardium, PAF induced a shortening of action potential duration at 90% level of repolarization (APD90)under non-ischemic conditions and a more pronounced shortening under early simulated ischemic conditions.

CONCLUSIONAMI and ischemia are associated with increased PAF levels in humans and pigs, which are further raised when fatal arrhythmia follows. The effects of PAF on the myocardium may be mediated by multiple ion channels.

Animals ; Arrhythmias, Cardiac ; blood ; etiology ; physiopathology ; Electrocardiography ; Female ; Heart ; physiopathology ; Humans ; Male ; Middle Aged ; Myocardial Ischemia ; blood ; complications ; physiopathology ; Platelet Activating Factor ; metabolism ; Swine

OBJECTIVETo study coronary artery stenosis, myocardial ischemia, and left ventricular dysfunction in dual source computed tomography (DSCT) coronary artery angiography.

METHODSTotally 32 patients underwent both DSCT and X-ray coronary angiography within one week to detect coronary artery stenosis separately. Meanwhile, the values of left ventricular myocardial mass (LVMM) , left ventricular ejection fraction (LVEF) , and left ventricular stroke volume (LVSV) were calculated using cardiac function software in DSCT. Electrocardiography was carried out to diagnose myocardial ischemia. The coronary artery stenosis, values of LVMM, LVEF, and LVSV, and myocardial ischemia were compared.

RESULTSThe results of DSCT and X-ray coronary angiography were not significantly different. LVMM, LVEF, LVSV, and myocardial ischemia were significantly different between two- or three-branch groups or between middle or severe groups (both P<0.05) . However, no such significant difference was observed between single and two branch groups and between mild and middle groups. There were no statistically different findings for LVEF and LVSV, but there was statistical deference between LVMM and myocardial ischemia (P<0.05) . For single branch and middle to severe stenosis in left anterior descending (LAD) coronary artery, right coronary artery, left circumflex coronary artery, only the values of LVMM,LVEF,and LVSV in LAD group showed significant difference (P<0.05) .

CONCLUSIONSMore stenotic branches and severer stenosis in coronary artery often are associated with higher incidence of myocardial ischemia and severer left ventricular dysfunction. The stenosis of LAD coronary artery has especially severe impact on cardiac functions. LVMM is a sensitive indicator for myocardial ischemia in coronary artery stenosis.

Aged ; Coronary Angiography ; methods ; Coronary Stenosis ; complications ; diagnostic imaging ; physiopathology ; Female ; Humans ; Male ; Middle Aged ; Myocardial Ischemia ; etiology ; Tomography, X-Ray Computed ; methods ; Ventricular Function, Left ; physiology

Based on human ventricular single cell mathematical model, a two-dimensional mesh of ventricular wall tissue was constructed. Through the increasing of the concentration of extracellular K+, we simulated the propagation of spiral wave in a condition under the influence of ischemia in 2-D human ventricular tissue. The results showed that along with the increase of ischemic level and size, the instability of spiral waves increased, and under the influence of certain ischemic level and size, spiral waves broke up. Through this simulation study of the effects of ischemia on spiral waves in 2-D human ventricular tissue, we explained the corresponding mechanism of the maintenance of ventricular tachycardia and the cause of ventricular fibrillation under the influence of ischemia.
Arrhythmias, Cardiac ; etiology ; physiopathology ; Computer Simulation ; Heart Ventricles ; Humans ; Models, Cardiovascular ; Myocardial Ischemia ; complications ; physiopathology ; Tachycardia, Ventricular ; etiology ; physiopathology ; Ventricular Fibrillation ; etiology ; physiopathology

OBJECTIVETo observe the development of arrhythmia induced by ischemia/reperfusion (I/R) of the right coronary artery in rabbits and the intervening effect of Chinese medicine Qiangxin Fumai Granule (QFG), a Chinese preparation for activating yang and promoting blood circulation, on it.

METHODSRabbit right coronary artery I/R model was adopted. Forty healthy adult rabbits were randomly divided into 5 groups, the sham-operation group, the model group, the atropine group, the high-dose QFG group, and the low-dose QFG group, eight in each group. The drugs were administered via duodenal perfusion 10 min after ischemia. The changes of AA interval before and after medication were observed and the scores of arrhythmia were calculated.

RESULTSDuring ischemia period, AA interval prolonged for more than 40 ms in the model group, and the scores of arrhythmia showed a rising trend along with the prolonging of ischemia, with the presence of atrial-ventricular block (AVB) and aggravating of sinus and atrial arrhythmia; during reperfusion period, the incidence of AVB decreased, and AA interval somewhat decreased. The AA intervals and scores of arrhythmia in the high and low-dose QFG groups were significantly lower than those in the model group respectively (P < 0.01 or P < 0.05).

CONCLUSIONQFG is beneficial for shortening AA interval and preventing arrhythmia induced by I/R.

Animals ; Anti-Arrhythmia Agents ; administration & dosage ; pharmacology ; therapeutic use ; Arrhythmias, Cardiac ; drug therapy ; physiopathology ; Coronary Artery Disease ; complications ; Dose-Response Relationship, Drug ; Drugs, Chinese Herbal ; administration & dosage ; pharmacology ; therapeutic use ; Female ; Male ; Myocardial Ischemia ; complications ; Myocardial Reperfusion Injury ; etiology ; physiopathology ; Phytotherapy ; Rabbits ; Random Allocation ; Treatment Outcome

AIMTo explore the effects of sleep deprivation (SD) on myocardium and its antioxygen index.

METHODS35 Sprague Dawley rats were randomly divided into five groups: Cage control, Tank control, SD 2 d, SD 4 d and SD 6 d. The "flower pot" technique was used to establish rats sleep deprivation model followed by record of surface electrocardiogram, detection of myocardium morphology changes under microscope and transmission electron microscope and investigation of MDA content and SOD activity of myocardial mitochondria.

RESULTSAfter sleep deprivation, heart rate increased and ECG showed ischemia of myocardium; subcellular organelles such as chromosome, endoplasmic reticulum, mitochondria, intercalated disk impaired, myofibril lysis or necrosis, and lipid peroxidation reaction effects spread widely; edema, bleeding of the microvessels and invasion of the monocytes could be seen in the lumen. The MDA level increased and SOD activity increased followed by a decreased trend.

CONCLUSIONSleep deprivation can induce damage on myocardium, and the stress especially oxygen stress caused by SD may be the possible mechanism.

Animals ; Electrocardiography ; Female ; Male ; Myocardial Ischemia ; etiology ; pathology ; physiopathology ; Oxidative Stress ; physiology ; Rats ; Rats, Sprague-Dawley ; Sleep Deprivation ; complications ; Superoxide Dismutase ; metabolism

The aim of this study was to determine if the potassium aspartate and magnesium (PAM) prevent reperfusion-induced ventricular arrhythmias (RIVA) in ischemia-reperfusion (IR) rabbit heart. Thirty rabbits were randomly divided into control, ischemia and PAM groups. Arterially-perfused rabbit left ventricular preparations were made, and transmural ECG as well as action potentials from both endocardium and epicardium were simultaneously recorded in the whole process of all experiments. In control group rabbit ventricular wedge preparations were continuously perfused with Tyrode's solution, and in ischemia group and PAM groups the perfusion of Tyrode's solution was stopped for 30 min. Then the ischemia group was reperfused with Tyrode's solution and the PAM group with Tyrode's solution containing 2.42 mg/L PAM, respectively. ECG, QT interval, transmural repolarization dispersion (TDR) and action potentials from epicardium and endocardium were simultaneously recorded, and the RIVA of the wedge preparation was observed. Compared with control group, TDR and incidence of RIVA were significantly increased in ischemia group (P<0.05). The incidence of RIVA in control, ischemia and PAM group was 0/10, 9/10 and 1/10, respectively. Compared with ischemia group, TDR and incidence of RIVA were significantly reduced in PAM group (P<0.05). Potassium aspartate and magnesium significantly reduce TDR and prevent ventricular arrhythmia in ischemic rabbit heart.
Arrhythmias, Cardiac/etiology ; Arrhythmias, Cardiac/*prevention & control ; Myocardial Ischemia/*complications ; Myocardial Ischemia/physiopathology ; Myocardial Reperfusion Injury/*complications ; Potassium Magnesium Aspartate/*therapeutic use ; Random Allocation