Influence of standard modifiable risk factors on ventricular tachycardia after myocardial infarction

Abstract

Abstract Background Sudden cardiac death due to ventricular tachyarrhythmia is the single greatest cause of death within two years after myocardial infarction (MI), especially early in the first 30 days. Purpose We aimed to assess the incidence of inducible ventricular tachycardia (VT) early after MI in those with standard modifiable risk factors (SMuRFs) versus those without. Methods Consecutive patients with LVEF ≤40% on day 3–5 after ST elevation myocardial infarction (STEMI) who underwent electrophysiology study were prospectively recruited. Positive EPS was defined as sustained monomorphic VT cycle length ≥200ms for > 10 seconds, or shorter duration if hemodynamic compromise occurred. The primary outcomes were inducibility of VT and all-cause mortality. Results A total of 410 patients, of which 126 had inducible VT on EPS, early after myocardial infarction were included. In our multiple regressions model, when smoking history was considered, ex-smokers were identified at increased risk of VT at EPS (adjusted OR 2.0, p=0.033) whilst those who never smoked or were current smokers had comparable risk. It also showed that the presence of any SMuRF apart from current smoker also conferred an increased risk of inducible VT (adjusted OR 1.9, p=0.043). For every 10 years increase in age the risk of death increased by a multiplicative factor of 1.3, for every 10% decrease in LVEF (%) the risk of death increased by a multiplicative factor of 1.9 and in patients with previous IHD, the risk of death was doubled. Neither the number of SMuRFs nor the presence of any SMuRF were associated with mortality. Conclusion In our cohort of patients with LVEF<40% early after STEMI who had an EPS to assess for inducible VT, either the presence of any of the three SMuRFs (hypertension, hypercholesterolemia or diabetes mellitus) or previous smoking doubled the chance of having VT induced. These data provide valuable information that could be integrated into clinical care protocols after myocardial infarction to improve long-term patient outcomes and further reinforces the need to modify SMuRFs in patients with ischemic heart disease.