Incidence, severity and clinical course of right ventricular involvement after acute inferior myocardial infarction; assessment by sequential 99Tcm-pyrophosphate scan and gated blood pool scan.

To evaluate the incidence, severity and clinical course of right ventricular (RV) involvement after acute inferior myocardial infarction (IMI), 78 patients (pts) with IMI were investigated by both 99Tcm-pyrophosphate (PYP) scan and gated blood pool scan (GBPS). GBPS was performed at admission and 10 days, whereas 99Tcm-PYP scan was performed at 3 to 6 days. RV uptake of PYP was demonstrated in 25 (32%) pts on 99Tcm-PYP scan and RV akinesis or moderate hypokinesis by GBPS was observed in 39 (50%) pts on the acute scan; 25 pts (Group A) with positive RV uptake and 14 pts (Group B) with no RV uptake. In the remaining 39 pts (Group C) had normal RV wall motion. Severely depressed RVEF improved nearly 10 points on the tenth day in Group A (from 30.8 +/- 12.3 to 40.9 +/- 6.7%, p less than 0.01) and Group B (from 35.6 +/- 8.2 to 44.5 +/- 10.5%, p less than 0.01), respectively. Group C showed normal RVEF (from 47.4 +/- 7.6 to 50.1 +/- 10.2%). Fourteen pts of 39 (Groups A and B) who had developed shock or hypotension improved strikingly after appropriate therapy except for one death during their hospital course. Our data demonstrated: some patients with RV dysfunction in IMI do not have severe necrosis as judged by PYP scanning, those with positive RV uptake and depressed RV function show a lower degree of recovery than those with no RV uptake, but start from a lower initial value of RV function, and the combination of 99Tcm-PYP scan and GBPS offers prognostic information in IMI with RV dysfunction.