Ventricular ectopic activity with spontaneous variant angina: Frequency and relation to transient ST segment deviation

This study was performed (1) to assess the frequency of ventricular ectopic activity (ventricular bigeminy, couplets, or ventricular tachycardia) during spontaneous variant angina; (2) to assess the relation between ventricular ectopy and the severity and duration of ischemia; and (3) to evaluate the precise temporal relation between episodes of ischemia and ventricular ectopy. Fifteen ambulatory patients with variant angina (12 men, 3 women, aged 50 ± 8 [mean ± SD] years) had Holter monitoring for 24 hours/week for 10 months (total, 10,238 hours of monitoring), from which the following were measured during each episode of ST deviation (elevation or depression): duration of ST deviation (minutes), maximal ST deviation (millivolts), presence of ventricular ectopic activity, and timing of ventricular ectopy in relation to ST deviation. Of 645 eplsodes of ST deviation, 79 (12.2%) had associated ectopy, almost all of which occurred in three patients. The 79 episodes of ST deviation with ectopy lasted 4.6 ± 3.3 minutes and averaged 0.16 ± 0.12 mV, whereas the 566 episodes of ST deviation without ectopy lasted 4.7 ± 6.1 minutes and averaged 0.17 ± 0.11 mV (NS in comparison to the 79 episodes with ectopy). Of 489 episodes of ST elevation, 72 (14.7%) were accompanied by ventricular ectopy; of 156 episodes of ST depression, only seven (4.5%) had ectopy (χ² = 11.531, p < 0.001). Of the 79 episodes of ventricular ectopy, almost all appeared during a period of increasing or maximal ST deviation, whereas only two appeared as ST deviation was resolving. Thus, in ambulatory patients with variant angina, (1) ventricular ectopy occurs only in an occasional individual and in association with only about 10% to 20% of episodes of transient ST deviation; (2) it occurs more often with transmural (ST elevation) than with subendocardial (ST depression) ischemia, but there is no clear relation between ectopy and the duration or magnitude of ST deviation; and (3) ectopy almost always appears during the initial 2 to 3 minutes of ST deviation, at a time when its magnitude is increasing or maximal.