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... in vivo, making RGS 4 a potential novel therapeutic target for atrial fibrillationArrhythmic burden in families with hypertrophic cardiomyopathy related to Myosin ...
A Opel, CLH Huang, A Grace, A Tinker... - ..., 2011 - Eur Heart Rhythm Assoc Abstract Introduction Long QT 3 (LQT3) is a cause of sudden cardiac death (SCD) by Torsade de Pointes (Td P). Sudden cardiac death often occurs during sleep, rest, and bradycardia, suggesting that heightened parasympathetic tone provokes Td P. It is ...
Methods and Results In a single centre, observational cohort study of 230 consecutively evaluated ICD recipients (median age 42 years, 97% primary prevention, 51% with ATP therapy) 56 non-clustered VA (39 treated with ATP and 17 with shocks) from 29 patients were analysed. Monomorphic ventricular tachycardia was the culprit arrhythmia in 86% of cases, ventricular fibrillation/flutter in 9% and polymorphic ventricular tachycardia in 5%. Prior to the onset of VA the rhythm was sinus in 67%, atrial fibrillation/flutter in 19 and 15% were paced ventricularly; tachycardia (cycle length 1 year follow-up without recurrence of VT following ablation). Activation and repolarization times during restitution curves were derived from 24 global sites per pt using semi-automated custom software. Fractionation was quantified as the number of deflections above a preset signal-to-noise threshold of the >30 Hz component of 1st differential of virtual unipolar electrograms. During steady-state pacing, no difference in activation recovery index (ARI) (198 ± 1 vs. 198 ± 1 ms), effective refractory period (ERP; 209 ± 4 vs. 213 ± 4 ms), or dispersion of repolarization (80 ± 25 vs. 84 ± 19 ms) existed between ARVC and control groups. The increase in conduction delay at ERP compared with steady state was raised in ARVC patients (43 ± 3 vs. 30 ± 3 ms, P = 0.01). Dispersion of repolarization increased at ERP to a maximum of 120 ± 26 ms in ARVC pts vs. 94 ± 29 ms in controls (P = 0.0012, Figure 1). A cut-off of measured dispersion of repolarization at 94 ms gave an 87% sensitivity and 58% specificity for ARVC diagnosis. EG Ms were more fractionated in the outflow tract of ARVC patients, with a mean number of complex deflections per electrogram of 3.90 ± 0.05 vs. 3.50 ± 0.05 (P = 0.0001) in steady state, increasing to 4.13 ± 0.11 vs. 3.54 ± 0.08 at ERP (P < 0.0001). No sustained ventricular arrhythmias were induced during the pacing protocol in any of the ARVC pts.
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... in vivo, making RGS 4 a potential novel therapeutic target for atrial fibrillationArrhythmic burden in families with hypertrophic cardiomyopathy related to Myosin ... |
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