Risk stratification following myocardial infarction in the thrombolytic era - A two-step strategy using noninvasive and invasive methods

Objectives. We prospectively performed a two-step risk assessment in patien ts in the early phase after acute myocardial infarction (MI). Background. Noninvasive methods like Holter electrocardiographic monitoring (HM) and determination of the left ventricular ejection fraction (EF) as w ell as the invasive technique of programmed ventricular stimulation (PVS) h ave been used to identify patients in the late phase after MI as candidates for prophylactic implantation of a cardioverter/defibrillator. However, it is unclear whether these results can be transferred to patients following acute MI. Methods. A series of 657 patients with acute MI (less than or equal to 75 y ears) underwent HM and EF. If one of the two methods yielded abnormal findi ngs (HM greater than or equal to 20 ventricular ectopic beats/h/greater tha n or equal to 10 ventricular pairs/day/ventricular tachycardia; EF less tha n or equal to 40%), PVS was done (abnormal PVS: induction of monomorphic ve ntricular tachycardia, duration >10 s, cycle length greater than or equal t o 230 ms). Results. Of 657 patients, 304 (46%) had either an abnormal HM or EF. The WS performed in 146 of 304 patients was abnormal in tt. During a mean follow- up of 37 months, there were 106 (16%) deaths, being sudden in 24 (3.6%), no nsudden cardiac in 45 (6.8%). The incidence of arrhythmic events (sudden ca rdiac death, symptomatic ventricular tachycardia, cardiac arrest) was 18% ( 4/22) with an abnormal PVS and only 4% (5/124) with a normal PVS (odds rati o 4.0, p = 0.032). Conclusions. The rate of arrhythmic events is low in post-MI patients in th e 1990s. Nevertheless, a two step risk stratification is helpful in selecti ng candidates for a defibrillator trial aiming at primary prevention of sud den cardiac death after MI. (C) 1998 by the American College of Cardiology.