Length of time between hospital admission and ventricular fibrillation or cardiac arrest complicating acute myocardial infarction: Effect on prognosis

We performed a community-wide study in metropolitan Baltimore to examine the prognostic role of length of time between hospital admission and ventricular fibrillation or cardiac arrest (VFib/CA) complicating acute myocardial infarction (MI). Rish of developing VFib/CA was particular marked in the first few hours after admission to the hospital. We compared 128 patients experiencing VFib/CA within 48 hours of admission and 80 patients developing these complications after more than 48 hours. Patients with 'early' VFib/CA exhibited a lower in-hospital case-fatality rate those with 'late' VFib/CA (67% versus 88%; p<.01). Likewise, of patients discharged alive from the hospital and followed for as long as six years a greater proportion of 38 with histories of 'early' VFib/CA survived than of the 11 who had experienced 'late' VFib/CA during hospital admission (.05<p<.10). These results suggest that whereas 'early' VFib/CA may reflect transitory myocardial electrical instability, 'late' VFib/CA may indicate chronic instability and thus imply a poor prognosis.