Morphologic characteristics of nonsustained ventricular tachycardia detected during Holter monitoring associated with atherosclerotic coronary artery disease.

Nonsustained ventricular tachycardia (VT) is an important prognostic indicator of outcome in patients with organic heart disease. The morphologic features of nonsustained VT were examined by obtaining a derived 12-lead electrocardiogram (ECGD) from a 24-hour Holter recording in 22 patients with nonsustained VT associated with coronary artery disease. A total of 60 nonsustained VT episodes were recorded. Of these, 20 were uniform and 40 were multiform. The mean rate of uniform episodes was faster (140 +/- 32 vs 124 +/- 16 beats/min; p < 0.01) and the duration longer (5.3 +/- 2.0 vs 4.0 +/- 1.0 beats; p < 0.02) than the multiform episodes. The majority (87%) of multiform episodes had only 2 different QRS configurations on the ECGD. Four distinct patterns of QRS configurations were seen within individual multiform nonsustained VT runs: type I--the initial QRS complex has 1 morphology and all subsequent complexes have another configuration; type II--the initial and terminal QRS complex has similar configuration; type III--the first 2 QRS complexes have similar configuration and all subsequent complexes have another morphology; and type IV--the QRS complexes have alternating morphologic features. These 4 different patterns may be related to the mechanism of nonsustained VT (reentry versus automaticity). Patients with multiple episodes of nonsustained VT frequently had differing patterns and morphologic features between episodes. Further studies are needed to evaluate the clinical importance of these findings.