Improved Clinical Risk Stratification In Patients With Long Qt Syndrome? Novel Insights From Multi-Channel Ecgs

BackgroundWe investigated whether multichannel ECG-recordings are useful to risk-stratify patients with congenital long-QT syndrome (LQTS) for risk of sudden cardiac death under optimized medical treatment.MethodsIn 34 LQTS-patients ( 11 male; age 31 +/- 13 years, QTc 478 +/- 51ms; LQT1 n = 8, LQT2 n = 15) we performed a standard 12-channel ECG and a 120-channel body surface potential mapping. The occurrence of clinical events (CE; syncope, torsade de pointes (TdP), sudden cardiac arrest (SCA)) was documented and correlated with different ECG-parameters in all lead positions.ResultsSeven patients developed TdP, four survived SCA and 12 experienced syncope. 12/34 had at least one CE. CE was associated with a longer QTc-interval (519 +/- 43ms vs. 458 +/- 42ms; p = 0.001), a lower T-wave integral (TWI) on the left upper chest (-1.2 +/- 74.4mV*ms vs. 63.0 +/- 29.7mV*ms; p = 0.001), a lower range of T-wave amplitude (TWA) in the region of chest lead V8 (0.10 +/- 0.08mV vs. 0.18 +/- 0.07mV; p = 0.008) and a longer T-peak-T-end time (TpTe) in lead V1 (98 +/- 23ms vs. 78 +/- 26ms; p = 0.04). Receiver-operating-characteristic (ROC) analyses revealed a sensitivity of 96% and a specificity of 75% ( area under curve (AUC) 0.89 +/- 0.06, p = 0.001) at a cut-off value of 26.8mV*ms for prediction of CE by TWI, a sensitivity of 86% and a specificity of 83% at a cut-off value of 0.11mV (AUC 0.83 +/- 0.09, p = 0.002) for prediction of CE by TWA and a sensitivity of 83% and a specificity of 73% at a cut-off value of 87ms ( AUC 0.80 +/- 0.07, p = 0.005) for prediction of CE by TpTe.ConclusionsOccurrence of CE in LQTS-patients seems to be associated with a prolonged, low-amplitude T-wave.