Functional mitral regurgitation after a first non-ST-segment elevation acute coronary syndrome: contribution to congestive heart failure

AIMS: Functional mitral regurgitation (MR) is a frequent complication after the acute phase of a myocardial infarction and plays an important role in the development of congestive heart failure (CHF) after a Q-wave myocardial infarction. Nevertheless, until now, the relevance of functional MR after a non-ST-segment elevation acute coronary syndrome (NSTSEACS) has been poorly addressed. Our aim was to assess the relationship between the presence or absence and the severity of functional MR after a first NSTSEACS and the development of CHF. METHODS AND RESULTS: Two hundred and seventy-nine patients discharged from hospital in NYHA functional classes I and II (71.7% men; mean age 66.3 +/- 13.2 years) after a first NSTSEACS were studied. Every patient underwent an echocardiographic study during the first week after the index NSTSEACS and were clinically followed-up. MR was detected in 40.1% patients. Patients were followed-up for a median time of 418 days (inter-quartile range: 295-561). Six patients (3.6%) in the group without MR and 15 patients (13.4%) in the group with MR required hospitalization due to CHF during follow-up. Only MR was found as an independent predictor of CHF development (HR = 1.8; 95% CI = 1.1-3.1; P = 0.02) and CHF development or cardiac death (HR = 2.1; 95% CI = 1.3-3.3; P = 0.01) in the long-term follow-up multivariable Cox regression analysis. CONCLUSION: There is an increased risk for subsequent CHF in patients with MR after a first NSTSEACS. The risk of CHF is closely related to the MR presence and severity. Thus, the detection of MR by means of Doppler echocardiography after a first episode of NSTSEACS is crucial.