203 Changes in T wave morphology prior to Onset of Ventricular Arrhythmias in ICDs

Introduction T wave morphological changes before onset of ventricular arrhythmia are poorly known. ICD-stored intracardiac electrograms (IEGM) present a unique opportunity for detecting temporal changes in repolarisation before initiation of VT/VF. Methods 56 implanted patients with St Jude medical ICDs (44 men, 63 ± 12 yo, mean EF 34 ± 15%) were prospectively enrolled. Eleven different T wave parameters were extracted from IEGM (T amplitude, T peak time, T end time, T duration between baseline crossing and between points of maximal slopes, T peak to T end, maximal ascending and descending slopes, timing of points of maximal slopes and T wave area). Averaged values of each parameter in recordings prior to VT/VF were compared to control recordings sharing comparable QRS and T wave morphology and similar heart rate in the same pts. Results 22 VT/VF episodes (24 ± 13 beats) and 13 baseline (25 ± 9 beats) (ns) were analyzed in 12 pts (1,8 episode/ pt). Mean heart rate was 71 ± 17 bpm for episodes and 66 ± 16 bpm for baseline recordings (ns). Significant differences were found in T wave amplitude and slopes. Durations and timings of the different parts of the T wave did not significantly vary. Conclusions Detection of T wave changes prior to VT/VF might be useful in predicting imminent arrhythmia occurrence. T wave amplitude is higher and T wave slopes are steeper before ventricular arrhythmia compared to baseline, without significant shortening of different repolarisation times. Download full-size image