Sudden Death After Myocardial Infarction

Abstract

Context Sudden cardiac death (SCD) after myocardial infarction (MI) has not recently been assessed in the community. Post-MI risk stratification for SCD commonly relies on baseline characteristics and little is known about the relationship between recurrent ischemia or heart failure (HF) and SCD. Objective To evaluate the risk of SCD after MI and the impact of recurrent ischemia and HF on SCD. Design, setting, and participants 2,997 Olmsted County residents experiencing an MI between 1979 and 2005. Main outcome measures SCD defined as out-of-hospital death due to coronary disease. Observed survival free of SCD compared to that expected in Olmsted County. Results During a median follow-up of 4.7 years (25th–75th percentile 1.6–7.1, date of last follow-up 02-29-2008), 1,160 deaths occurred, 282 (24%) SCD. The 30-day cumulative incidence of SCD was 1.2% (95% confidence interval [CI] 0.8–1.6%). Thereafter, the rate of SCD was constant at 1.2%/year yielding a 5-year cumulative incidence of 6.9% (95% CI 5.9% to 7.9%). The 30-day incidence of SCD was 4-fold higher than expected (standardized mortality ratio=4.2, 95% CI 2.9 to 5.8). In the year thereafter, the risk of SCD was lower than expected (standardized mortality ratio=0.66, 95% CI 0.50 to 0.85). The risk of SCD declined over time (hazard ratio=0.62, 95% CI 0.44 to 0.88 for MIs in 1997–2005 compared to 1979–1987; p =0.03). Recurrent events, ischemia (n=842) or HF (n=365), occurred in 2,080 patients. After adjustment for baseline characteristics, recurrent ischemia was not associated with SCD (hazard ratio=1.26, 95% CI 0.96 to 1.65; p=0.09), while HF markedly increased the risk of SCD (hazard ratio= 4.20, 95% CI 3.10 to 5.69; p<0.001) Conclusions The risk of SCD is highest during the first month after MI and declined over time. SCD is independently associated with HF but not with recurrent ischemia.

Sudden Cardiac Death in Heart Failure

“…8 Although the absolute rate of SCD is highest in the first 30 days after the event and decreases gradually with time, 9 rates are still high in certain subsets of postinfarction patients, and the degree of left ventricular systolic dysfunction and symptoms (New York Heart Association [NYHA] class) are powerful predictors for SCD in these patients. 10 In the chronic stage of ischemic cardiomyopathy (months and years after the initial infarction), the presumed mechanism of SCD is an electrical event caused by ventricular arrhythmias often originating from areas of prior infarcted myocardium that are adjacent to dense scar that has formed over time. Residual endomyocardial fibers survive, probably because of perfusion from the ventricular cavity or retrograde perfusion through sinusoidal channels.…”

Implantable Cardioverter-Defibrillators in Sudden Cardiac Death Prevention: What Guidelines Don't Tell

“…The risk of SCD in myocardial infarction (MI) survivors has also declined significantly over the past 30 years, presumably due to early reperfusion and optimal medical therapy practices [27]. Recurrent ischemia may not be significantly associated with SCD, whereas heart failure due to MI markedly increases the risk of SCD [27].…”

“…The risk of SCD in myocardial infarction (MI) survivors has also declined significantly over the past 30 years, presumably due to early reperfusion and optimal medical therapy practices [27]. Recurrent ischemia may not be significantly associated with SCD, whereas heart failure due to MI markedly increases the risk of SCD [27]. Interestingly, acute ischemia is an established cause of VF and polymorphic VT [28], whereas cardiac death in patients with nonischemic dilated cardiomyopathy and functional class IV heart failure is more often due to bradyarrhythmia or electromechanical dissociation than due to ventricular tachyarrhythmias [29].…”

Gender-dependent profile of heart rate turbulence parameters in patients after acute myocardial infarction treated invasively

“…patients who survived sudden cardiac death (SCD) or those with severely reduced left ventricular ejection fraction (LVEF), is easily identifiable, while the majority of patients with myocardial infarction (MI) and intermediate risk of SCD are still a challenge for risk stratification. That is why there is still a clinical need to search for the optimal combination of SCD risk factors, especially in women who are at the highest risk of SCD after MI, in order to improve the prediction of long-term outcomes [1]. Although there are many defined risk stratification parameters, none of them meets all requirements (e.g.…”