183 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 (EGM) present a unique opportunity for detecting temporal changes in repolarisation before initiation of VT/VF. Methods 57 implanted patients with St Jude Medical ICDs (45 men, 64 ± 12 yo, mean EF 34 ± 15%) were prospectively enrolled. Eleven different T wave parameters were extracted from EGM (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). 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 23 VT/VF episodes (24 ± 13 beats) and 13 baseline (25 ± 9 beats) (ns) were analyzed in 12 pts (1,9 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, T wave maximal slopes, T peak time and timing of the T wave maximal ascending slope (although ns when corrected by the heart rate). Conclusions T wave amplitude is higher, T wave slopes are steeper and initial parts of the T wave are earlier before ventricular arrhythmia compared to baseline. Detection of T wave changes prior to VT/VF might be useful in predicting imminent arrhythmia occurrence. Download full-size image Example of T wave changes before VT