[Heart arrest in acute pulmonary embolism. An anatomo-clinical study].

The Authors describe the modalities and mechanisms of cardiac arrest (CA) in the course of acute pulmonary embolism (PE). Clinical data refer to 39 CA episodes occurred in 28 patients with massive or submassive PE; autopsy data are from 26 of 28 patients of the same series. One-third of 39 CAs proved at least momentarily reversible; two-thirds were irreversible. Data analysis showed that most CA episodes, reversible or otherwise, seen in the course of PE were due to electromechanical dissociation (EMD). In fact, EMD was responsible for 12 of 13 reversible CAs and 22 of 26 irreversible arrests. EMD usually follows shock, but may occur unheralded. When EMD-induced CA is at least temporarily reversible, the heart rate is often normal or high and QRS complexes are narrow. In most cases the sudden rise of right ventricular afterload came on top of a pre-existing myocardial damage, for the most part of ischemic, sometimes necrotic, origin. In this series, therefore, it seems quite difficult to tell "primary" from "secondary" forms of EMD. External cardiac massage continued for as long as 40 minutes was associated in some cases with a bolus fibrinolytic infusion within minutes from occurrence of CA. Five of 7 patients so treated made a temporary recovery and two survived; at autopsy, none of the 5 patients who died showed any evidence of bleeding attributable to local injury.