Abstract 10618: Paradoxical Nocturnal Sympathetic Activation and Spontaneous Ventricular Fibrillation in Resuscitated Patients Without Apparent Structural Heart Diseases
Background. Nocturnal dominance of cardiopulmonary arrest episodes has been detected in patients with Brugada syndrome (BS). However, clinical and electrophysiologic features, autonomic activity and its circadian variation have not been fully clarified in idiopathic ventricular fibrillation (IVF).
Methods.We enrolled consecutive 30 patients with cardiopulmonary arrest survivors without apparent structural heart diseases, including IVF (n=15), BS (VF-BS: n=12) and excluding 3 long QT syndrome. For comparison, twenty-one normal control subjects with early repolarization in inferior and or lateral leads (ILER) were enrolled. Because all IVFs had a CPA episode at least, we compared clinical features and ILER changes by Na channel blocker provocation between IVF and BS, and compared analyses of separate QT dynamics (QT/RR)and heart rate variability (HRV: HR, SDNN, HF, LF/HF) using 24-hour ambulatory ECG during daytime awaking and sleeping periods between IVF and control.
Results. Nocturnal spontaneous VF episodes were detected in 8 /15 IVF(53%) and 7/12 VF-BS (58%). ILER were detected in 9 /15 IVF (60%) and 6/12 BS (50%). ILER did not significantly change after pilsicainide provocation in both syndromes except J-point after 40ms in VF-BS. In HRV analyses, HF during sleeping is significantly higher than that during daytime awaking in control (459.7±491.6 vs. 190.5.1±171.2 ms2, P<0.01), but not in IVF (256.4±432.3 vs. 120.0.1±97.0 ms2, P=NS). LF/HF during sleeping is significantly lower than that during daytime awaking in control (2.5±1.6 vs. 3.9±1.7, P<0.01) and is significantly higher in IVF than in control subjects (3.9±2.4 vs. 2.5±1.6, P<0.05).
Conclusions. Clinical and electrophysiologic features of IVF were similar to those of BS. Sympathetic tone significantly elevated during night sleeping in IVF compared to control subjects, and may be related to spontaneous VF initiation, suggesting sympathetic activation blockade may have a possible therapeutic approach even in nocturnal sudden cardiac death.
- © 2012 by American Heart Association, Inc.