Heart Care Info - Heart Disease Prevention & Treatment

... of endocardial and multi-site pacing are dependent on the left ventricular electrical activation pattern and presence of ischaemic heart disease: insights from electro- ...

A Opel, CLH Huang, A Grace, A Tinker... - ..., 2011 - Eur Heart Rhythm Assoc A. Opel1 (Presenting author), CL-H. Huang2, A. Grace3, and A. Tinker1 1University College London, London UK; 2University of Cambridge, Cambridge UK; and 3Papworth Hospital, Cambridge UK Introduction: Long QT 3 (LQT3) is a cause of sudden cardiac death (SCD) by Torsade ...

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.