Frequency and prognostic impact of right ventricular involvement in acute myocardial infarction

Objective: Right ventricular (RV) involvement complicating myocardial infarction (MI) is thought to impact prognosis, but potent RV markers for risk stratification are lacking. Therefore, the aim of this trial was to assess the frequency and prognostic implications of concomitant structural and functional RV injury in MI.

Methods: Cardiac magnetic resonance (CMR) was performed in 1235 patients with MI (ST-elevation myocardial infarction: n=795; non-STEMI: n=440) 3 days after reperfusion by primary percutaneous coronary intervention. Central core laboratory-masked analyses included structural (oedema representing reversible ischaemia, irreversible infarction, microvascular obstruction (MVO)) and functional (ejection fraction, global longitudinal strain (GLS)) RV alterations. The clinical end point was the 12-month rate of major adverse cardiac events (MACE).

Results: RV ischaemia and infarction were observed in 19.6% and 12.1% of patients, respectively, suggesting complete myocardial salvage in one-third of patients. RV ischaemia was associated with a significantly increased risk of MACE (10.1% vs 6.2%; p=0.035), while patients with RV infarction showed only numerically increased event rates (p=0.075). RV MVO was observed in 2.4% and not linked to outcome (p=0.894). Stratification according to median RV GLS (10.2% vs 3.8%; p<0.001) but not RV ejection fraction (p=0.175) resulted in elevated MACE rates. Multivariable analysis including clinical and left ventricular MI characteristics identified RV GLS as an independent predictor of outcome (HR 1.05, 95% CI 1.00 to 1.09; p=0.034) in addition to age (p=0.001), Killip class (p=0.020) and left ventricular GLS (p=0.001), while RV ischaemia was not independently associated with outcome.

Conclusions: RV GLS is a predictor of postinfarction adverse events over and above established risk factors, while structural RV involvement was not independently associated with outcome.