Significance of abnormal and late ventricular signals in ventricular tachycardia ablation of ischemic and nonischemic cardiomyopathies.

BACKGROUND: Abnormal ventricular signals (AVS) are the cornerstone of substrate-based ventricular tachycardia (VT) ablation in sinus rhythm. Signal characterization of AVS in ischemic and nonischemic cardiomyopathies has never been performed. OBJECTIVE: The purpose of this study was to describe ventricular signal abnormalities in 3 different pathologies and examine their association with the diastolic component of VT circuits. METHODS: A total of 45 patients (15 ischemic cardiomyopathy [ICM], 15 arrhythmogenic cardiomyopathy [ACM], 15 dilated cardiomyopathy [DCM]) who had undergone VT ablation with >50% of the diastolic pathway of the VT circuit recorded were studied. AVS were classified into late potentials (LPs) and continuous fractionated ventricular signals (CFVS), and their characteristics and correlation with the diastolic pathway of VT circuits were analyzed. RESULTS: Seventy-five VT circuits were analyzed. Bipolar scars were greatest in ICM endocardially (53 cm2 ICM vs 36 cm2 ACM vs 25 cm2 DCM; P = .010) and in ACM epicardially (98 cm2 ACM vs 25 cm2 ICM vs 24 cm2 DCM; P = .005). Location of the VT diastolic interval coincided with AVS location in 54% of VTs in ICM, 89% in ACM, and 72% in DCM (P = .036). There was a trend toward a greater association of diastolic intervals coinciding with LPs than with CFVS (78% vs 57%; P = .052) (69% diastolic intervals in ICM coincided with LPs, 33% with CFVS; P = .063). All patients (100%) with CFVS in ACM had VT diastolic components arising from CFVS (33% ICM, 64% DCM; P = .049). Positive predictive value for LPs vs CFVS was 77.8% vs 56.7%, and sensitivity was 67.3% vs 32.7%, respectively. CONCLUSION: The nature of abnormal signals in different cardiomyopathies reflects underlying pathology. LPs rather than CFVS seem to be more linked to diastolic components of VT circuits, especially in ICM. LPs have greater sensitivity and specificity for VT; however, CFVS may be of more relevance in ACM.

Platelet Reactivity in Hepatitis C Virus-Infected Patients on Dual Antiplatelet Therapy for Acute Coronary Syndrome.

Background Coronary artery disease (CAD) has been recognized as a serious and potentially life-threatening complication of Hepatitis C Virus (HCV) infection. High on-treatment platelet reactivity has been associated with high risk of ischemic events in patients with CAD, but data regarding the association with HCV infection are still lacking. This post hoc analysis aims to assess high on-treatment platelet reactivity, severity of CAD, and long-term outcomes of patients with acute coronary syndrome (ACS) who were infected with HCV. Methods and Results Patients with ACS who were infected with HCV (n=47) were matched to patients with ACS and without HCV (n=137) for age, sex, diabetes mellitus, hypertension, and renal function. HCV-infected patients with ACS had higher levels of platelet reactivity (ADP10-light transmittance aggregometry, 56±18% versus 44±22% [P=0.002]; arachidonic acid-light transmittance aggregometry, 25±21% versus 16±15% [P=0.011]) and higher rates of high on-treatment platelet reactivity on clopidogrel and aspirin compared with patients without HCV. Moreover, HCV-infected patients with ACS had higher rates of multivessel disease (53% versus 30%; P=0.004) and 3-vessel disease (32% versus 7%; P<0.001) compared with patients without HCV. At long-term follow-up, estimated rates of major adverse cardiovascular events (cardiac death, nonfatal myocardial infarction, and ischemia-driven revascularization) were 57% versus 34% (P=0.005) in HCV- and non-HCV-infected patients with ACS, respectively. In addition, thrombolysis In Myocardial Infarction (TIMI) major bleeding rates were higher in HCV-infected patients (11% versus 3%; P=0.043) compared with noninfected patients. Multivariable analysis demonstrated that HCV infection was an independent predictor of high on-treatment platelet reactivity, severity of CAD, and long-term outcome. Conclusions In this hypothesis-generating study, patients with ACS and HCV infection showed increased on-treatment platelet reactivity, more severe CAD, and worse prognosis compared with patients without HCV.