Exploring QT interval changes as a precursor to the onset of ventricular fibrillation/tachycardia.
In the present study, we have retrospectively analyzed the corrected QT (QTc) interval before spontaneous episodes of sudden cardiac arrest in patients with a wearable cardioverter defibrillator. Corrected QT interval was measured for all normal beats from 32 recordings of baseline rhythm and compared to normal rhythm before a paired spontaneous cardiac arrhythmia. Before arrhythmia, the QTc (505 +/- 73 ms) was not significantly longer than the baseline rhythm (497 +/- 73 ms) (P = .23). Considering ventricular tachycardia (VT) events only (12 patients), event QTc (526 +/- 75 ms) was not significantly longer than baseline QTc (520 +/- 74 ms) (P = .41). Considering fast VT/ventricular fibrillation (VF) events only (20 patients), event QTc (494 +/- 70 ms) was not significantly longer than baseline QTc (483 +/- 71 ms) (P = .26). The influence of QTc as a measure to indicate an impending VT event in a variety of VT/VF patients remains unclear.
Department of Electrical and Computer Engineering, Clarkson University, Potsdam, NY 13699, USA. lewickat@clarkson.edu
Aaron
A
Lewicke
Katherine
K
Bellor
Katie
K
Dillon
Thomas
T
Kaib
Steven
S
Szymkiewicz
Stephanie
S
Schuckers
D000465:Algorithms; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017180:Tachycardia, Ventricular / Q000175:diagnosis*; D014693:Ventricular Fibrillation / Q000175:diagnosis*