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CMR detected key characteristics after right ventricular ischemic injury
Masci P. Circulation. 2010;122:1405-1412.
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Early postinfarction right ventricular injury was common in patients with acute STEMI and characterized by the presence of myocardial edema, late gadolinium enhancement and functional abnormalities, researchers reported in Circulation.
“Experimental data show that the [right ventricle] is more resistant to ischemia than the left ventricle,” the researchers commented in their study. “We have demonstrated that [right ventricular] edema and late gadolinium enhancement, reflecting ischemic myocardial injury, are often present early after reperfusion of STEMI.”
The study included 242 consecutive patients from three European centers between May 2006 and September 2008. Patients had reperfused acute STEMI and were excluded if they had prior MI or revascularization, atrial fibrillation, cardiogenic shock, renal failure, contraindications to CV magnetic resonance (CMR) and any known clinical condition that may affect right ventricular function.
At 1 week and 4 months after MI, patients were studied with CMR. Researchers performed T2-weighted scans to depict myocardial edema and post-contrast CMR to determine late gadolinium enhancement.
Study results showed that after infarction, right ventricular edema was found in more than half the patients (51%) and was regularly associated with late gadolinium enhancement (31% of patients). In anterior LV infarcts, right ventricular edema was found in 33% and late gadolinium enhancement in 12% of the cases. Researchers also recorded an inverse relationship between baseline regional and global right ventricular functions and the presence and extent of right ventricular edema and right ventricular late gadolinium enhancement.
Additionally, at follow-up, researchers observed a decrease in frequency (10.3%) and extent of right ventricular late gadolinium enhancement (P<.001). Multivariable analysis revealed the presence of right ventricular edema as an independent predictor of right ventricular global function improvement during follow-up (beta coefficient=0.221; P=.003).
The researchers said the key findings of their research were: temporary right ventricular dysfunction is frequently present early after infarction and is determined primarily by right ventricular ischemic involvement; although the right ventricle is preferentially involved in inferior LV infarcts, it is not uncommon to find similar, albeit less extensive, abnormalities in anterior LV infarcts as well; a significant reduction in frequency and size of right ventricular late gadolinium enhancement is observed at follow-up; and persistent right ventricular late gadolinium enhancement occurs in a minority of patients, most likely representing postinfarction myocardial fibrosis, and is associated with adverse right ventricular remodeling and worse function at follow-up.
“These findings support previous clinical and animal studies showing that the [right ventricle] is more resistant to ischemia than the LV and that acute postinfarction [right ventricular] dysfunction is likely an expression of viable rather than irreversibly damaged myocardium,” the researchers said. “Moreover, it is important to realize that in patients with anterior LV infarction, ischemia may extend toward the adjacent [right ventricular] free wall and lead to transient [right ventricular] dysfunction.”
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