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Background: Ventricular arrhythmias (VAs) have never been systematically investigated in patients with myocarditis at different stages.Objectives: The purpose of this study was to compare baseline and follow-up characteristics of VAs in patients with active myocarditis (AM) versus previous myocarditis (PM).Methods: A total of 185 consecutive patients (69% males, age 44 ± 15 years, left ventricular ejection fraction 49 ± 14%) with myocarditis and VA at index hospitalization, including ventricular fibrillation, ventricular tachycardia (VT), nonsustained ventricular tachycardia (NSVT), and Lown's grade ≥2 premature ventricular complexes, were enrolled. AM and PM groups were defined based on endomyocardial biopsy and cardiac magnetic resonance findings. A subset of patients (n = 46, 25%) also underwent electroanatomic mapping and VA transcatheter ablation.Results: At presentation, AM patients (n = 123, 66%) more commonly had ventricular fibrillation (8 cases vs. 0 cases; p = 0.053), and both irregular (61% vs. 11%; p < 0.001) and polymorphic VA (NSVT and VT: 19% vs. 2%; p = 0.002; premature ventricular complexes: 63% vs. 16%; p < 0.001). Only in PM patients with NSVT or VT, the dominant morphology (right-bundle branch block with superior axis) was 100% predictive of abnormal LV inferoposterior substrate at both cardiac magnetic resonance and electroanatomic mapping. At 27 ± 7 months prospective follow-up, 55 patients (30%) experienced malignant VA (AM vs. PM, p = 0.385). Although a prevalence of polymorphic and irregular VA was confirmed in AM patients with persistent inflammation in follow-up (58%), a predominance of monomorphic and regular VA was found in AM patients after myocarditis healing (42%), as well as in PM patients (all p < 0.001).Conclusions: In myocarditis patients, polymorphic and irregular VA are more common during the active inflammatory phase, whereas monomorphic and regular VA are associated with healed myocarditis. [ABSTRACT FROM AUTHOR]

Introduction: Cardiac resynchronization therapy (CRT) device implantation guided by an electroanatomic mapping system (EAMS) is an emerging technique that may reduce fluoroscopy and angiography use and provide information on coronary sinus (CS) electrical activation. We evaluated the outcome of the EAMS-guided CRT implantation technique in a multicenter registry. Methods: During the period 2011-2014 we enrolled 125 patients (80% males, age 74 [71-77] years) who underwent CRT implantation by using the EnSite system to create geometricmodels of the patient's cardiac chambers, build activation mapping of the CS, and guide leads positioning. Two hundred and fifty patients undergoing traditional CRT implantation served as controls. Success and complication rates, fluoroscopy and total procedure times in the overall study population and according to center experience were collected. Centers that performed ∼10 were defined as highly experienced. Results: Left ventricular lead implantation was successful in 122 (98%) cases and 242 (97%) controls (P = 0.76). Median fluoroscopy time was 4.1 (0.3-10.4) minutes in cases versus 16 (11-26) minutes in controls (P < 0.001). Coronary sinus angiography was performed in 33 (26%) cases and 208 (83%) controls (P < 0.001). Complications occurred in 5 (4%) cases and 17 (7%) controls (P = 0.28). Median fluoroscopy time (median 11 minutes vs. 3 minutes, P < 0.001) and CS angiography rate (55% vs. 21%, P < 0.001) were significantly higher in low experienced centers, while success rate and complications rate were similar. Conclusions: EAMS-guided CRT implantation proved safe and effective in both high- and low experienced centers and allowed to reduce fluoroscopy use by ≈75% and angiography rate by ≈70%. [ABSTRACT FROM AUTHOR]

Aims: Patients with non-ischaemic cardiomyopathy (NICM) and ventricular tachycardia can be categorized as anteroseptal (AS) or inferolateral (IL) scar sub-types based on imaging and voltage mapping studies. The aim of this study was to correlate the baseline electrocardiogram (ECG) with endo-epicardial voltage maps created during ablation procedures and identify the ECG characteristics that may help to distinguish the scar as AS or IL.Methods and Results: We assessed 108 baseline ECGs; 72 patients fulfilled criteria for dilated cardiomyopathy whereas 36 showed minimal structural abnormalities. Based on the unipolar low-voltage distribution, the scar pattern was classified as predominantly AS (n = 59) or IL (n = 49). Three ECG criteria (PR interval < 170 ms or QRS voltage in inferior leads <0.6 mV or a lateral q wave) resulted in 92% sensitivity and 90% specificity for predicting an IL pattern in patients with preserved ejection fraction (EF). The four-step algorithm for dilated cardiomyopathy included a paced ventricular rhythm or PR > 230 ms or QRS > 170 ms or an r ≤ 0.3 mV in V3 having 92 and 81% of sensitivity and specificity, respectively, in predicting AS scar pattern. A significant negative correlation was found between the extension of the endocardial unipolar low voltage area and left ventricular EF (rs = -0.719, P < 0.001). The extent of endocardial AS unipolar low voltage was correlated with PR interval and QRS duration (rs = 0.583 and rs = 0.680, P < 0.001, respectively) and the IL epicardial unipolar low voltage with the mean voltage of the limb leads (rs = -0.639, P < 0.001).Conclusion: Baseline ECG features are well correlated with the distribution of unipolar voltage abnormalities in NICM and may help to predict the location of scar in this population. [ABSTRACT FROM AUTHOR]