Pathological features of witnessed out-of-hospital cardiac arrest presenting with ventricular fibrillation

Abstract

Objectives: To determine which characteristic pathological features are predictive of the presenting rhythm and survival in victims of community cardiac arrest. Design: Case-controlled retrospective autopsy study. Setting: County of Nottinghamshire with a total population of 993 914 and an area of 2183 square kilometres. Subjects: Between January 1, 1991 and December 31, 1994, 1535 witnessed cardiac arrests attended by the Nottinghamshire Ambulance Service, of which 1083 had an autopsy performed. Results: Ischaemic heart disease accounted for 72.3% of cases with a further 3.6% of deaths from other cardiac causes and the remainder from non-cardiac causes. Old healed myocardial infarction was present in 39.4%, and visible fresh occlusive thrombus was found in 23.8% of cases overall. Logistic regression analysis of deaths from cardiac causes revealed that younger age (odds ratio of 0.98 (95% CI 0.97–0.99)), two vessel coronary artery disease (odds ratio of 1.65 (95% CI 1.08–2.52)) and heart weight greater than 500 grams (odds ratio of 1.56 (95% CI 1.12–2.17)) were found to be independent predictors of developing ventricular fibrillation compared to other rhythms of arrest. Being male, visible occlusive thrombus and having survived a previous myocardial infarction were found not to be independent variables. There were no outstanding pathological features in the 31 patients who survived to hospital admission and subsequently died, compared with non-survivors who were considered to have died from a cardiac cause. Conclusions: Among those who had a witnessed out-of-hospital cardiac arrest from a cardiac cause, increasing heart weight (the most likely cause of which is left ventricular hypertrophy), younger age and two vessel coronary artery disease appear to be much more important pathological features in the development of ventricular fibrillation than a previous myocardial infarction and fresh visible occlusive thrombus.