Isorhythmic Atrioventricular Dissociation with haemodynamic instability in a patient with a pacemaker

Abstract

We report probable isorhythmic atrioventricular dissociation (IRD) causing significant hypotension in a 94 year-old male with a dual chamber pacemaker undergoing a craniotomy. Poorly responsive to beta-blockade and escalating doses of vasopressors, hypotension and dysrhythmia were successfully treated with induction of asynchronous atrioventricular (AV) pacing. In patients with reduced cardiac reserve, the loss of coordinated atrial and ventricular activity, as in IRD, can substantially reduce cardiac output. In these patients, methods to restore AV synchrony should be quickly sought.