Info

Abbreviations: SCD, sudden cardiac death; PPA, positive predictive accuracy; PVCs, premature ventricular couplets.

aAfter thrombolysis.

Abbreviations: SCD, sudden cardiac death; PPA, positive predictive accuracy; PVCs, premature ventricular couplets.

aAfter thrombolysis.

Low-amplitude (<25 V) late potentials along with increased filtered QRS duration (>120 ms) are suggestive evidence of slowed and fragmented conduction. Absence of these findings in the postinfarct setting is associated with a 96-99% negative predictive value for sustained ventricular tachycardia or sudden death after 1 yr (132,134-137). The combined use of ambulatory ECG variables, signal-averaged ECG, and HRV leads to a greater positive predictive accuracy for cardiac events (134-136).

Programmed electrical stimulation inducing monomorphic ventricular tachycardia with cycle length >230 ms performed 2-4 wk after MI patients with ejection fraction <35% is a good predictor of spontaneous sustained ventricular tachycardia (138,139). Pedretti et al. (140) reported a sensitivity of 81% and specificity of 97% for inducibility of ventricular tachycardia to predict future arrhythmia in patients after MI who had two or more of the following: ejection fraction <40%, late potentials, or high-grade ectopy. Zoni-Barriso et al. (139), using up to two extra stimuli for induction of monomorphic ventricular tachycardia, found inducibility to have a sensitivity, specificity, and positive predictive accuracy of 55, 99, and 67%, respectively, for arrhythmic event. Patients were selected if they had either ejection fraction <40%, late potentials, or complex ventricular arrhythmias. Lack of inducibility in this high-risk population carries a better prognosis. The Multicenter Automatic Defibrillator Implantation Trial (MADIT) showed that in a select group of patients enrolled 4 wk to 2 yr after MI (with ejection fraction <35%, an episode of nonsustained ventricular tachycardia, and nonsuppressible ventricular tach-yarrhythmia during electrophysiologic study) randomization to automatic implantable cardioverter-defibrillator was associated with significantly improved survival rates compared to conventional therapy (141). The Multicenter Unsustained Tachycardia Trial (MUSTT) (142) showed that electrophysiologically guided therapy with implantable defibrillators, but not with antiarrhythmic drugs in patients with coronary disease, LV ejection fraction <40%, and asymptomatic, nonsustained ventricular tachycardia reduced the risk of cardiac arrest and sudden death from arrhythmia. The use of noninva-sive predictors of sudden cardiac death to select candidates for electrophysiologic studies to identify the highest risk patient for sudden cardiac death after AMI is shown in Fig. 12.

Arrhythmia Evaluation for Risk of SCD After MI

Ejection Fraction <35-40%

Yes No

> 2 Noninvasive Risk Markers

Was this article helpful?

0 0
Your Heart and Nutrition

Your Heart and Nutrition

Prevention is better than a cure. Learn how to cherish your heart by taking the necessary means to keep it pumping healthily and steadily through your life.

Get My Free Ebook


Post a comment