Syncope and conduction disturbances following sublingual nifedipine for hypertension.

We present a case of a 79-year-old woman with periods of syncope, complete heart block (CHB), and ventricular standstill during periods of increased vagal tone following sublingual nifedipine for hypertension. The syncopal episodes were associated with periods of elevated vagal tone (micturition and vomiting) with one monitored episode showing a clear time course of emesis; CHB then ensued, progressing to ventricular standstill with loss of consciousness that resolved over several minutes. Although nifedipine is not thought to affect conduction at current clinical dosages, it seems likely that the additive effects of nifedipine and elevated vagal tone produced the observed conduction abnormalities. This is the first case report of nifedipine administration followed by syncope and conduction disturbances.