Concealed mechanical bradycardia: an indication for permanent pacemaker implantation.

We report a 51-year-old man with severe ischemic cardiomyopathy and heart failure in whom incessant bigeminal ventricular ectopy failed to generate a detectable arterial pressure. This created a mechanical bradycardia despite an adequate electrical heart rate. Dual chamber pacing increased the effective heart rate and allowed discontinuation of an intraaortic balloon pump from which the patient could not otherwise be weaned.