Papillary Muscle Infarction, Mitral Regurgitation, and Long-Term Prognosis
In patients with acute myocardial infarction, the presence of mitral regurgitation (MR) is clinically important. The reported prevalence of MR after myocardial infarction varies. Bursi et al1 have pointed out that the prevalence varies between 1.6% and 19% in angiographic studies, but may be higher in echocardiographic studies. Indeed, among 773 patients undergoing echocardiography <30 days after infarction, MR was present in 50% of patients, of which MR was mild in 38% patients and moderate to severe in 12%.2 Thus, the variability in the reported prevalence of MR seems to be related to the technique used to assess its presence and to quantify its severity. It may also be related to the timing of MR assessment after infarction. In a recent report from the Valsartan in Acute Myocardial Infarction (VALIANT) study, the prevalence of MR was quantitatively assessed at baseline, 1 month, and 20 months in 341 patients after infarction.3 In this study, MR worsened by 1 degree in 78 patients (23%) and by 2 degrees in 10 patients (3%) after 20 months of follow-up. Conversely, 47 patients (14%) improved in MR by ≥1 degree, whereas in the remaining 206 patients (60%), the severity of MR remained unchanged. In particular, at 20 months follow-up, 15% of patients had moderate to severe MR.
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It has been reported in various studies that patients with MR after infarction have a worse prognosis. In 1190 patients with acute infarction, the hazard ratios for development of heart failure, as compared with patients without MR, were 2.8 for patients with mild MR and 3.6 for patients with moderate to severe MR.4 In the same population, the hazard ratios for death were 1.2% (mild MR) and 2.0% (moderate to severe regurgitation). Similarly, Bursi et al2 reported a relative …