The signal averaged ECG in patients with nonsustained ventricular tachycardia — a perspective

Nonsustained ventricular tachycardia is a frequent accompaniment of severe structural heart disease, but it is also discovered occasionally in patients without structural heart disease. It is unique among the arrhythmias clinicians are called upon to deal with because most patients with this arrhythmia have no symptoms directly attributable to it. Rather, this arrhythmia is of interest and concern because of its prognostic significance. The prognostic significance depends on the presence and type of underlying heart disease. The discovery of nonsustained ventricular tachycardia in patients with recent myocardial infarction and abnormal ventricular function identifies a group of patients at significantly increased risk for sudden death1–5. Likewise, patients with hypertrophic cardiomyopathy and nonischemic dilated cardiomyopathies who have nonsustained ventricular tachycardia are at increased risk for sudden death6–12. In contrast, asymptomatic subjects without structural heart disease in whom nonsustained ventricular tachycardia is discovered are not at significantly increased risk for sudden death13. Thus, the presence of nonsustained ventricular tachycardia identifies some populations of patients that are at increased risk for sudden cardiac death. The arrhythmia is therefore a useful epidemiological tool.