Incidence, clinical significance and prognosis of ventricular fibrillation in the early phase of myocardial infarction.

Of 1265 patients admitted to the CCU with the diagnosis of acute MI, 96 (7.6%) developed ventricular fibrillation within 72 hours following admission. Of these 96, 35 (36.5%) had secondary VF associated with left ventricular failure; they had a high in-hospital mortality of 57.1%. The remaining 61 (63.5%) had primary VF, i.e. VF occurring in the absence of significant LV failure. Fourteen of these (23%) died in hospital: 9 due to PVF (3 during the first episode, 6 during a recurrence). This mortality figure was significantly higher (P less than 0.001) than the mortality of 10% seen among patients who did not experience VF. Primary VF showed a recurrence rate of 20%. Compared with the 1061 patients who left the hospital without primary VF, the 61 subjects with this rhythm disorder were older, had larger infarcts and more frequent complications, such as pericarditis, conduction abnormalities, frequent ventricular premature contractions and signs of right ventricular failure. These findings, in contrast with a widely held view, suggest that primary VF may carry a guarded prognosis.