Key result
Class I drugs significantly prolonged filtered QRS in patients with inducible sustained ventricular tachycardia (p<0.05), which correlated with SVT cycle length prolongation (p<0.01).
Why the study?
Do class I antiarrhythmic drugs alter signal-averaged electrocardiogram parameters and correlate with SVT cycle length in patients with sustained ventricular tachycardia?
Observational (n=13)
Do class I antiarrhythmic drugs alter signal-averaged electrocardiogram parameters and correlate with SVT cycle length in patients with sustained ventricular tachycardia?
Changes in signal-averaged ECG parameters after class I drug administration correlate with SVT cycle length prolongation and may help predict SVT inducibility.
Answers are grounded in this paper and cite their sources.
Signal-averaged ECG may help assess class I drug effects in inducible VT; hypothesis-generating and needs prospective validation.
Evaluation of signal-averaged electrocardiograms (SAECGs) has been reported to be useful for predicting the patients with sustained ventricular tachycardia (SVT) combined with organic heart disease and at high risk for sudden cardiac death. However, the relationship between drug efficacy and SAECGs has not been established. We studied the effects of class I drugs on SVT using SAECGs. The study group consisted of 13 patients with SVT who underwent serial electropharmacologic trials. In 7 trials, SVT could not be induced after administration of class I drugs (group 1). In 17 trials, SVT was still inducible (group 2). Filtered QRS in group 2 were significantly prolonged after administration of class I drugs (p < 0.05). The prolongation of the SVT cycle length was correlated with the prolongation of the original QRS (p < 0.05) and with prolongation of the filtered QRS after administration of class I drugs (p < 0.01). The evaluation of the effects of class I drugs on SAECGs may be useful in predicting the inducibility of SVT and SVT cycle length.
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Doi et al. (1997) conducted an observational in Sustained ventricular tachycardia (n=13). Class I antiarrhythmic drugs vs. Baseline (pre-drug administration) was evaluated on Filtered QRS prolongation and correlation with SVT cycle length (p=<0.05). Class I drugs significantly prolonged filtered QRS in patients with inducible sustained ventricular tachycardia (p<0.05), which correlated with SVT cycle length prolongation (p<0.01).
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