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- Philip F. Binkley, MD, MPH⁎ ()
- ↵⁎Davis Heart & Lung Research Institute, 110R DHLRI, 473 West 12th Avenue, Columbus, Ohio 43210-1252
I read with interest the paper by McNamara et al. (1), which supports the findings of our previous report of a logistic model that identifies factors associated with restoration of normal ventricular function in this patient population (2). As we noted in that paper, which indeed references the marked improvement in left ventricular function observed in the placebo group of the IMAC (Intervention in Myocarditis and Acute Cardiomyopathy) trial, we have entered a new era in the natural history of dilated cardiomyopathy in which restoration of normal ventricular function may be anticipated in a significant number of patients. This demands that we better identify those patients who are likely to recover normal ventricular function. Identification of those who have a high probability of recovery will allow early implementation of more aggressive therapies in those who are not likely to recover, and will point towards interventions that may augment the factors found to be associated with restoration of normal ventricular function.
In particular, our report identified progressive increases in QRS duration, male gender, ischemic etiology of heart failure, and a history of diabetes mellitus as factors that decrease the probability of recovery. The probability of recovery increased with increasing systolic blood pressure at the time of initial diagnosis. Indeed, the report by McNamara et al. (1) is in agreement with 3 of these factors. They also find that female gender and increasing blood pressure are associated with recovery of ventricular function. Electrocardiographic QRS duration is known to correlate highly with ventricular chamber size, and therefore, it is not surprising that they find end-diastolic dimension to be a significant correlate with ventricular recovery. The cohort in their study did not strictly match that in our study, being focused on those with recent-onset cardiomyopathy. They specifically excluded patients with ischemic heart disease and diabetes, and therefore, our data provide insight into different etiologies of cardiomyopathy and the important comorbidity of diabetes. In addition, the average time to recovery of left ventricular function in our study was 40.3 ± 4.7 months, providing total patient-years equivalent to that in the study by McNamara et al. (1), even though our cohort size was smaller. Our data show that recovery can be a slow process, and it would be interesting to see how the factors they identify influence recovery over longer periods of time.
The recognition that patients with dilated cardiomyopathy can recover normal ventricular function raises important questions. Importantly, it is unknown whether return to normal ventricular function represents a true recovery from the cardiomyopathic process or is in fact a “remission” with persistence of normal function dependent on continued medical therapy. Indeed, we have reported a small series of patients who have “relapsed” with discontinuation of medical therapy (3). Should the current American Heart Association/American College of Cardiology classification of heart failure stage include a new category designating those who have returned to normal cardiac function? As we continue to understand this new era in the natural history of cardiomyopathy, we are challenged to address these and other issues.
- American College of Cardiology Foundation