Predictive characteristics of holter-based postinfarction risk stratifiers appear superior to electrophysiological testing.
Prevalent low-frequency (PLF) oscillation of heart rate and turbulence slope (TS) are both powerful postmyocardial infarction (MI) risk factors. Abnormal composite risk stratifier (CRS) was defined as abnormal PLF or abnormal TS when PLF was not analyzable. We compared the predictive power of CRS with the previously published predictive value of conventional electrophysiological (EP) testing based on the presence of nonsustained ventricular tachycardia (NSVT) and inducibility of sustained ventricular tachycardia/fibrillation (VT/VF) during programmed ventricular stimulation (PVS). PLF and TS were calculated from baseline Holter recordings in the placebo population of European Amiodarone Infarction Myocardial Infarction Trial (EMIAT trial) (n = 633; LVEF </= 40%; 87 deaths; 22-month follow-up). Previously established cut-off values of PLF >/= 0.1 Hz and TS </= 2.5 ms/RR were used. The clinical characteristics of the EMIAT population were similar to those of the Multicenter Unsustained Tachycardia Trial (MUSTT trial). Therefore, we compared the predictive power of CRS and conventional PVS using the values of 35% VT/VF inducibility during PVS in NSVT patients, and a 33% and 50% increase in all-cause and arrhythmic mortality, respectively, associated with VT/VF inducibility in MUSTT. Projecting the predictive power of PVS in MUSTT into the EMIAT population yielded a sensitivity of 13.8% and 14.0% and positive predictive value (PPV) of 27.9% and 14.0% for all-cause and arrhythmic mortality, respectively, whereas an abnormal CRS was associated with sensitivities of 46.0% and 46.5% and PPV of 37.4% and 18.7%. Compared with the noninvasive Holter-based CRS, invasive PVS appears inferior in the identification of high-risk post-MI patients with left ventricular dysfunction.
Wichterle
Dan
D
Department of Cardiac and Vascular Sciences, St. George's Hospital Medical School, London, UK. wichterle@hotmail.com
Simek
Jan
J
Camm
John
J
Malik
Marek
M
D015716:Electrocardiography, Ambulatory; D004594:Electrophysiology; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000401:mortality / Q000503:physiopathology*; D011237:Predictive Value of Tests; D018570:Risk Assessment