Reduced apical rotation linked to functional mitral regurgitation after ST-elevation MI

A significant association exists between a reduced apical rotation and functional mitral regurgitation in patients with acute ST-elevation myocardial infarction (MI), suggesting a potential novel pathophysiological mechanism, reports a study.

“Our study sheds light on the complex mechanisms underlying functional mitral regurgitation following acute MI,” the researchers said.

A total of 200 patients with first acute ST-elevation MI undergoing percutaneous coronary intervention from July 2019 to October 2022 were enrolled in this retrospective study. Of these, 164 were included in the final analysis.

The researchers compared patients with moderate or worse functional mitral regurgitation to those with less functional mitral regurgitation for baseline characteristics, MI parameters, and myocardial features including apical rotation. They also evaluated the determinants of functional mitral regurgitation via logistic regression analyses.

Of the included patients, 14 (8.5 percent) had significant functional mitral regurgitation, which significantly correlated with reduced apical rotation (2.2 ° vs 5.7 °; p<0.001), independent of other variables. [Am J Med 2025;138:1278-1284]

Other echocardiographic findings in patients with significant functional mitral regurgitation were as follows: mildly reduced ejection fraction (43 percent vs 48 percent; p=0.010), mildly enlarged left ventricular diameter (5.1 vs 4.8 cm; p=0.022), and enlarged left atrial diameter (4.2 vs 3.8 cm; p=0.004).

In the adjusted model including clinically relevant variables, each decrease in apical rotation increased the odds of significant acute functional mitral regurgitation by 2.14 (95 percent confidence interval, 1.35–3.40; p=0.001).

“Reduced apical rotation may add diagnostic precision to assessing cardiac function post-MI and functional mitral regurgitation,” the researchers said. “By highlighting the relationship between left ventricular twist and mitral regurgitation, clinicians could more accurately identify patients at risk for clinical worsening, allowing for timely interventions.”

Mechanism

It remains to be known what the cause of reduced apical rotation and functional mitral regurgitation is. However, a previous study suggests a link between left ventricular dysfunction in patients following ST-elevation MI and reduced apical rotation. [Int J Cardiovasc Thorac Surg 2021;7:64-69]

“Our results suggest that the incidence of functional mitral regurgitation significantly correlated with ST elevation in certain leads on electrocardiography, predominantly leads 1, V3, and V4,” the researchers said. “However, troponin levels and the culprit artery are not significantly associated with functional mitral regurgitation.”

There are other aetiologies that can help explain the reduction in apical rotation. For instance, “invasive procedures may reduce left ventricular twist as part of a decrease in global contractile state,” while negative inotropic agents may also lessen circumferential contractility. [J Am Soc Echocariogr 2008;21:493-499; Eur J Radiol 2010;74:484-491]

Moreover, mid-wall fibrosis in patients with nonischaemic cardiomyopathy may lead to reduced apical rotation. These mechanisms potentially contribute to worsening of apical rotation and ischaemic mitral regurgitation and requires further studies. [J Cardiovasc Magnetic Reson 2016;18:1]

“Considering these findings, we propose that the reduction in twist is a contributing factor to the development of functional mitral regurgitation,” the researchers said. “These conclusions may support various approaches to managing ischaemic mitral regurgitation and refining patient care.”