BACKGROUND In an 84-year-old patient with acute right ventricular myocardial infarction (RVI), complete heart block, and low cardiac output, a significant increase in blood pressure (BP) and decrease in right atrial pressure (RAP) were accidentally observed during the performance of high-rate ventricular pacing. METHODS Based on that observation, the acute effects of high-rate cardiac pacing (VVI or AAI) on BP and RAP were studied in 15 consecutive patients (67.4 +/- 7.7 years), with hemodynamically significant RVI. Ten had advanced heart block and five had sinus bradycardia. Cardiac pacing with simultaneous recording of BP and RAP at intrinsic rhythm and at heart rates of 70, 90, 110, 130 beats/min was performed. RESULTS Systolic BP (SBP) increased significantly from 94.6 +/- 15 mmHg during intrinsic rhythm to 101.9 +/- 13.8 mmHg-127 +/- 12.2 mmHg at heart rates 70-130 beats/min (p < 0.0001). Diastolic BP (DBP) also increased from 48.2 +/- 8.7 to 53.9 +/- 3.7-69.1 +/- 3 mmHg at heart rates 70-130 beats/min, (p < 0.014-0.0001). Mean RAP decreased from 14.5 +/- 5 to 14.1 +/- 5 mmHg-11.1 +/- 4.1 mmHg at heart rates 70-130 beats/min (p = 0.16-0.0001). Significant elevation of SBP (p < 0.007), DBP (p < 0.0075), and decrease of RAP (p < 0.038) were also detected by comparing the usual pacing rate at 70 beats/min with pacing rates at 90-130 beats/min. CONCLUSIONS These findings, if demonstrated over a prolonged period during the acute state of RVI, may influence the management of patients with RVI to include high-rate cardiac pacing, probably in the range of 80-110 beats/min.