Heart rhythm : the official journal of the Heart Rhythm Society
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Higher levels of resting heart rate (HR) have been associated with sudden cardiac death (SCD) but mechanisms are poorly understood. We hypothesized that severe left ventricular systolic dysfunction (LVSD) and HR-modulating drugs explain the HR-SCD relationship. ⋯ Contrary to expectations, the significant relationship between increased resting HR and SCD persisted even after adjustment for LVSD and HR-modulating drugs. These findings suggest a potential role for additional novel interventions/therapies that modulate autonomic tone.
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Multicenter Study Clinical Trial
Atrioventricular delay programming and the benefit of cardiac resynchronization therapy in MADIT-CRT.
The optimal atrioventricular pacing delay (AVD) in cardiac resynchronization therapy (CRT) remains to be determined. ⋯ Our findings indicate that in MADIT-CRT programming, the CRT AVD <120 ms was associated with a greater clinical and echocardiographic response to CRT.
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Little is known about the clinical and prognostic impact of early repolarization (ER) on patients with Brugada syndrome (BrS), especially those with documented ventricular fibrillation (VF). ⋯ The prevalence of ER in inferolateral leads was high and an especially persistent form of ER was associated with a worse outcome in BrS patients with documented VF.
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Low-voltage termination of ventricular tachycardia (VT) and atrial fibrillation has shown promising results; however, the mechanisms and full range of applications remain unexplored. ⋯ A novel 2-stage low-voltage defibrillation protocol using the excitable gap extent to time multiple stimuli defibrillated VF with the least energy by first converting VF into VT and then terminating VT.
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Conducting channels within scars form the substrate for infarct-related ventricular tachycardia (VT) and are targeted during catheter ablation. Whether the amount of left ventricular scar (LVS) affects outcomes after VT ablation is not known. ⋯ LVS burden derived from 12-lead ECGs is a significant and independent predictor of mortality and clinical outcomes in subjects with infarct-related VT.