RESUMO
BACKGROUND@#The long-term predicted value of microvolt T-wave alternans (MTWA) for ventricular tachyarrhythmia in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) remains unclear. Our study explored the characteristics of MTWA and its prognostic value when combined with an electrophysiologic study (EPS) in patients with ARVC.@*METHODS@#All patients underwent non-invasive MTWA examination with modified moving average (MMA) analysis and an EPS. A positive event was defined as the first occurrence of sudden cardiac death, documented sustained ventricular tachycardia (VT), ventricular fibrillation, or the administration of appropriate implantable cardioverter defibrillator therapy including shock or anti-tachycardia pacing.@*RESULTS@#Thirty-five patients with ARVC (age 38.6 ± 11.0 years; 28 males) with preserved left ventricular (LV) function were recruited. The maximal TWA value (MaxValt) was 17.0 (11.0-27.0) μV. Sustained VT was induced in 22 patients by the EPS. During a median follow-up of 99.9 ± 7.7 months, 15 patients had positive clinical events. When inducible VT was combined with the MaxValt, the area under the curve improved from 0.739 to 0.797. The receiver operating characteristic curve showed that a MaxValt of 23.5 μV was the optimal cutoff value to identify positive events. The multivariate Cox regression model for survival showed that MTWA (MaxValt, hazard ratio [HR], 1.06; 95% confidence interval [CI], 1.01-1.11; P = 0.01) and inducible VT (HR, 5.98; 95% CI, 1.33-26.8; P = 0.01) independently predicted positive events in patients with ARVC.@*CONCLUSIONS@#MTWA assessment with MMA analysis complemented by an EPS might provide improved prognostic ability in patients with ARVC with preserved LV function during long-term follow-up.
Assuntos
Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Arritmias Cardíacas , Diagnóstico , Displasia Arritmogênica Ventricular Direita , Diagnóstico , Eletrocardiografia , Métodos , Eletrofisiologia , Métodos , Teste de Esforço , Seguimentos , Taquicardia Ventricular , Diagnóstico , Função Ventricular Esquerda , FisiologiaRESUMO
Background@#The long-term predicted value of microvolt T-wave alternans (MTWA) for ventricular tachyarrhythmia in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) remains unclear. Our study explored the characteristics of MTWA and its prognostic value when combined with an electrophysiologic study (EPS) in patients with ARVC.@*Methods@#All patients underwent non-invasive MTWA examination with modified moving average (MMA) analysis and an EPS. A positive event was defined as the first occurrence of sudden cardiac death, documented sustained ventricular tachycardia (VT), ventricular fibrillation, or the administration of appropriate implantable cardioverter defibrillator therapy including shock or antitachycardia pacing.@*Results@#Thirty-five patients with ARVC (age 38.6 ± 11.0 years; 28 males) with preserved left ventricular (LV) function were recruited. The maximal TWA value (MaxValt) was 17.0 (11.0–27.0) μV. Sustained VT was induced in 22 patients by the EPS. During a median follow-up of 99.9 ± 7.7 months, 15 patients had positive clinical events. When inducible VT was combined with the MaxValt, the area under the curve improved from 0.739 to 0.797. The receiver operating characteristic curve showed that a MaxValt of 23.5 μV was the optimal cutoff value to identify positive events. The multivariate Cox regression model for survival showed that MTWA (MaxValt, hazard ratio [HR], 1.06; 95% confidence interval [CI], 1.01–1.11; P = 0.01) and inducible VT (HR, 5.98; 95% CI, 1.33–26.8; P = 0.01) independently predicted positive events in patients with ARVC.@*Conclusions@#MTWA assessment with MMA analysis complemented by an EPS might provide improved prognostic ability in patients with ARVC with preserved LV function during long-term follow-up.
RESUMO
Objective To evaluate myocardial apoptosis with 99Tcm-C2A-GST myocardial imaging using the recombined C2A domain of Synaptotagmin Ⅰ by gene engineering. Methods ( 1 ) The C2A gene was inserted into the prokaryotic glutathione S-transferate (GST) fusion protein expression plasmid pGEX-6P-1. The recombinant plasmid was transformed into E. coli BL21. C2A-GST fusion protein was purified after BL21 was induced with isopropyl-β-D-1-thiogalactopyranoside (IPTG). (2)The activity of fusion protein was identified by cell binding test with fluorescein-5-isothiocyanate (FITC)-C2A-GST. (3) The C2A-GST fusion protein was labeled with 99Tcm using 2-iminothiophene hydrocoride method. Radiochemical purity was determined with thin layer chromatography. (4)99Tcm-C2A-GST (7.4 MBq) was injected to ischemia-reperfusion rat models through tail vein. The image was acquired with SPECT at 1 h after injection, and then hearts were removed, rinsed with saline and dyed with triphenyl tetrazolium coride (TTC). The ischemic myocardium was separated from the viable myocardium and was weighted. Its radioactivity was measured by gamma counting. The difference of uptake of radiotracer between ischemic myocardium and normal myocardium was compared using percentage activity of injected dose per gram of tissue ( % ID/g) with standard deviation. SPSS 12.0 and t-test were used for data analysis. Results ( 1 ) C2A-GST fusion protein wassuccessfully expressed and its relative molecular weight was 3.8 × 104. (2) FITC-C2A-GST binding to apoptotic cells could be observed by fluorescent microscopy. (3) The radiochemical purity of 99Tcm-C2A-GST was (98.90 ±0.43)%. (4)The imaging studies showed that there was focal uptake of radioactivity in the ischemic myocardium. In vitro uptake of 99Tcm-C2A-GST was (2.41 ±0.32) % ID/g by the ischemic myocardium, however 99Tcm-C2A-GST-N-hydroxysuccinimide (C2A-GST-NHS) was (0. 82 ± 0. 24) % ID/g. There was statistically significant difference between those two groups (t = 10. 6, P ＜0.01 ). Conclusion The C2A domain of Synaptotagmin Ⅰ expressed by gene engineering can be used as the tracer for noninvasive detection of ischemic myocardium in the ischemia-reperfusion rat model.