Clinical and angiographic outcome of patients with acute inferior myocardial infarction

OBJECTIVES: This study sought to determine the procedural success and the in-hospital outcome after primary coronary angioplasty in patients with acute inferior myocardial infarction and right ventricular involvement (RVI). BACKGROUND: RVI represents an easily detectable, highly prevalent subset of acute inferior infarction associated with poor outcome even in the era of thrombolysis. Primary PTCA may offer advantages in patients with inferior infarction involving the right ventricle. METHODS: Primary coronary angioplasty with optimal stenting was performed in 87 of 88 consecutive patients presenting within 24 hours after onset of acute inferior myocardial infarction. On the basis of right precordial ST segment elevations at admission, patients were classified into those without (n=61) and those with RVI (n=27). The patients were followed prospectively for angiographic success at 10 days and for in-hospital clinical outcome. RESULTS: Baseline characteristics including age, severity of coronary artery disease, proportion of stent implantation, and occurrence of cardiogenic shock were comparable. Patients with RVI had larger infarct sizes (lactate dehydrogenase level: 962 vs 580 U/l, P=0.03), developed more often complete atrioventricular block (18.5 vs. 2%, p=0.0038), needed more often parasympatholytics (48.1 vs 18.8%, p<0.001), and had a substantially higher incidence of the Bezold-Jarisch reflex (29.6 vs 6.6%, p<0.01) following reperfusion.Success of recanalization therapy acutely and at 10 days, as well as in hospital mortality were similar in patients with and without RVI (88.5 vs. 85.2%, 79.3 vs. 84.7%, 7.4 vs 9.8%). However, patients with RVI revealed a greater lumen gain acutely after PTCA (2.49 vs. 2.13 mm, p=0.025) and experienced less frequently major cardiac events (14.8 vs. 36.1%, p=0.04) which included reinfarction, re-ischemia, coronary bypass grafting, stent thrombosis, and cardiac death. In addition, procedural success was established more rapidly (fluoroscopy time: 10 vs 15 min., p=0.032) and with less contrast material (242 vs 295 ml, p=0.015) in patients with RVI. This is probably due to the more proximal location (84.6 vs 6.6%, p<0.0001) and the larger reference diameter (3.17 vs. 2.79 mm, p=0.03) of the occluded right coronary artery. CONCLUSIONS: Primary PTCA is an appropriate reperfusion strategy in patients with RVI. Further comparative studies are required to compare the effectiveness of primary PTCA with early thrombolytic therapy in this high risk setting.