Role of signal averaging of the surface QRS complex in selecting patients with nonsustained ventricular tachycardia and high grade ventricular arrhythmias for programmed ventricular stimulation.
Signal averaging of the surface QRS complex was performed before programmed ventricular stimulation in 53 individuals with high grade ventricular arrhythmias or nonsustained ventricular tachycardia, or both. An abnormal signal-averaged electrocardiogram (ECG) was recorded in 22 patients and was associated with inducible ventricular tachycardia in 12 (55%) of the 22. In contrast, a normal signal-average ECG was associated with inducible tachycardia in only 1 (3%) of 31 individuals (p less than 0.005). The group with inducible tachycardia had a longer duration of the signal-averaged QRS complex (124 +/- 19 versus 96 +/- 26 ms) and of low amplitude signals (44 +/- 13 versus 29 +/- 11 ms) (p less than 0.005). In addition, the root mean square voltage of the terminal 40 ms was lower in this group (20 +/- 14 versus 48 +/- 34 microV, p less than 0.005). Twenty-seven of the 53 subjects had a prior myocardial infarction; 17 (63%) of the 27 had an abnormal signal-averaged ECG, and ventricular tachycardia was inducible in 10 (59%) of the 17. A normal signal-averaged ECG was recorded in 10 of the 27 patients and only 1 (10%) of these 10 had inducible tachycardia. An abnormal signal-averaged ECG had a 91% sensitivity and a 56% specificity with respect to subsequent induction of tachycardia. During long-term follow-up, 2 (15%) of the 13 patients with inducible ventricular tachycardia who were treated with electrophysiologically guided antiarrhythmics therapy died suddenly; the remaining 11 patients (85%) are alive 15 +/- 10 months after electrophysiologic testing.(ABSTRACT TRUNCATED AT 250 WORDS)
Winters
S L
SL
Department of Medicine, Mount Sinai School of Medicine, City University of New York, New York 10029.
Stewart
D
D
Targonski
A
A
Gomes
J A
JA
D000368:Aged; D001145:Arrhythmias, Cardiac / Q000503:physiopathology* / Q000628:therapy; D002304:Cardiac Pacing, Artificial / Q000379:methods; D009202:Cardiomyopathies / Q000503:physiopathology; D004562:Electrocardiography; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D009203:Myocardial Infarction / Q000503:physiopathology; D011379:Prognosis; D011446:Prospective Studies; D013610:Tachycardia / Q000503:physiopathology* / Q000628:therapy