BACKGROUND: The diagnosis of right ventricular involvement (RVI) in STEMI is based mainly on clinical, electrocardiographic and echocardiographic (2DE) findings, which are highly insensitive.
OBJECTIVE: The purpose of this study was to determine the incidence of RVI based on cardiac magnetic resonance imaging (CMR) in STEMI patients and to characterize STEMI patients with RVI.
METHODS: We prospectively evaluated 87consecutive patients with a first STEMI undergoing primary PCI. All patients underwent CMR on day 4-5 after the onset. CMR (1.5 T) was performed using a standard protocol including steady state free precession for function evaluation and late gadolinium enhancement (LGE) sequences for myocardial injury evaluation. RVI was defined as RVEF<45%. The 2DE and angiographic findings of patients with and without RVI were compared.
RESULTS: Mean age was 58±10 y.o and 90% were male. Anterior STEMI was present in 41 (47%) patients. RVI was documented in 23/41 (56%) patients. Among them, reduced RV function on 2DE was demonstrated in 1 patient (4%) and on ECG RV4r ST- elevation was noted in only 13/23 patients (57%).
14/23 (61%) with RVI demonstrated LGE in the RV free wall in continuum with the inferior septum and 5 (22%) showed septal LGE. No RV LGE was documented in 4 (17%) patients. In the presence of RV free wall RV LGE - RCA was the infarct related artery (IRA) in 60%; LAD was the IRA in septal RV LGE; Circumflex was the IRA in the absence of RV LGE.
CONCLUSIONS: RVI in STEMI is under-diagnosed utilizing 2DE or ECG changes. CMR was able to demonstrated myocardial RV involvement. While in patients with RVI due to septal involvement there was predominance of LAD disease, RCA was the IRA in those with evidence of RV free wall involvement.
