Value of acoustic cardiography in the clinical diagnosis of coronary heart disease.

BACKGROUND: To investigate the clinical value of acoustic cardiography in the diagnosis of coronary artery disease (CAD) and post-percutaneous coronary intervention (PCI) early asymptomatic left ventricular systolic dysfunction. METHODS: Inpatients in the department of cardiology were included in the research (n = 315); including 180 patients with angina pectoris and 135 patients with acute anterior wall myocardial infarction after emergency PCI did not present with signs and symptoms of heart failure. Color Doppler echocardiography, brain natriuretic peptide, acoustic cardiography examination were performed. The patients were divided into four groups: non-CAD group (n = 60), CAD group (n = 120), MIREF group (EF% < 50%, n = 75), and MINEF group (EF% ≥ 50%, n = 60). RESULTS: Acoustic cardiography parameters EMATc, systolic dysfunction index, S3 strength and S4 strength in the MIREF group were higher than those in MINEF group (p < .05), and the MINEF group was higher than CAD group (p < .05). S3 strength (area under the curve [AUC] 0.67, 95% CI 0.585-0.755, p < .001) and S4 strength (AUC 0.617, 95% CI 0.536-0.698, p = .011) are useful in the diagnosis of CAD. S3 strength (AUC 0.942, 95% CI 0.807-0.978, p < .001) was superior to other indicators in the diagnosis of early left ventricular systolic dysfunction after myocardial infarction. CONCLUSION: S4 combined with STT standard change can improve the diagnosis of CAD. Acoustic cardiography can be used as a non-invasive, rapid, effective, and simple method for the diagnosis of asymptomatic left ventricular systolic dysfunction in the early stage after myocardial infarction.

Effects of hypokalemia on transmural dispersion of ventricular repolarization in left ventricular myocardium.

OBJECTIVE: To observe effects of hypokalemia on transmural heterogeneity of ventricular repolarization in left ventricular myocardium of rabbit, and explore the role of hypokalemia in malignant ventricular arrhythmia (MVA). METHODS: A total of 20 rabbits were randomly divided into control group and hypokalemic group. Isolated hearts in the control group were simply perfused with modified Tyrode's solution, and were perfused with hypokalemic Tyrode's solution in hypokalemic group. Ventricular fibrillation threshold (VFT), 90% monophasic action potential repolarization duration (APD90) of subepicardial, midmyocardial and subendocardial myocardium, transmural dispersion of repolarization (TDR) and C×43 protein expression in three layers of myocardium were measured in both groups. RESULTS: VFT in the control group and the hypokalemic group were (13.40 ± 2.95) V, and (7.00 ± 1.49) V, respectively. There was a significant difference between two groups (P<0.01). APD90 of three myocardial layers in the hypokalemic group were significantly prolonged than those in the control group (P<0.01). ΔAPD90 in the hypokalemic group and the control group were (38.10 ± 10.29) ms and (23.70 ± 5.68) ms, and TDR were (52.90 ± 14.55) ms and (36.10 ± 12.44) ms, respectively. ΔAPD90 and TDR in the hypokalemic group were significantly higher than those in the control group (P<0.05), and the increase in APD90 of midmyocardium was more significant in the hypokalemic group. Cx43 protein expression of all three myocardial layers were decreased significantly in the hypokalemic group (P<0.01), and ΔCx43 was significantly increased (P<0.05). Reduction of Cx43 protein expression was more significant in the midmyocardium. CONCLUSIONS: Hypokalemic can increase transmural heterogeneity of C×43 expression and repolarization in left ventricular myocardium of rabbit, and decrease VFT and can induce MVA more easily.