Hypotension and shock associated with heart block and other forms of atrioventricular (AV) dissociation frequently accompany right ventricular infarction ( RVI ). Such patients do not invariably improve with ventricular pacing. We evaluated the relative effects of AV dissociated rhythms (ventricular pacing or nodal rhythm) and AV synchronous rhythms (atrial pacing, AV sequential pacing, or return to normal sinus rhythm) in seven patients with RVI complicated by AV dissociation, who had hypotension or shock. Hemodynamic monitoring demonstrated the characteristic features of RVI in all patients. Restoration of AV synchrony resulted in a highly significant (p less than or equal to 0.001) increase in systolic blood pressure (88.0 +/- 16.5 mm Hg to 133.0 +/- 21.8 mm Hg), cardiac output (3.8 +/- 0.9 L/min to 5.7 +/- 0.9 L/min), and stroke volume (40.5 +/- 6.9 cc to 61.0 +/- 10.0 cc). We conclude that restoration of normal AV synchrony has a marked effect on stroke volume in this setting and that atrial or AV pacing can reverse hypotension and shock in RVI complicated by AV dissociation.