Faculty Bibliography

Iron deficiency is common in heart failure (HF) patients, and is associated with increased risk of adverse clinical outcomes. Clinical trials of intravenous iron supplementation in iron-deficient HF patients have demonstrated short-term improvement in functional capacity and quality of life. In some trials, the benefits of iron supplementation were independent of the hemoglobin levels. Additional investigations of iron supplementation are needed to characterize the mechanisms contributing to clinical benefit and long-term safety in HF.

Left ventricular (LV) remodeling is the most common term used to describe the functional, structural, myocellular, and interstitial changes that occur in response to myocardial injury and/or chronic changes in myocardial loading conditions. Progression of LV remodeling over time in response to neurohormonal activation, increased wall stress, and inflammatory signaling pathways is associated with an increased risk of major morbidity and mortality. LV reverse remodeling describes the process by which an injured LV with a dilated spherical phenotype may return toward a normalization of ventricular structure and function, either spontaneously or in response to therapeutic interventions. LV reverse remodeling can occur in response to interventions that mitigate the source of myocardial injury, or that reduce or eliminate the neurohormonal and/or hemodynamic factors that contribute to the progression of the LV remodeling process. In this article, we review selected studies that demonstrate the LV reverse remodeling process in response to pharmacological, pacemaker device, and mechanical circulatory support device interventions. Future therapies targeting the physiological, neurohormonal, and/or molecular signaling pathways to effect reverse remodeling may further improve clinical outcomes in heart failure patients.

Exercise duration during exercise treadmill testing (ETT) predicts long-term outcome among asymptomatic patients with mitral regurgitation. However, the prognostic value of preoperative exercise duration in patients who undergo mitral valve surgery is unknown. We examined findings among 45 prospectively followed (average 9.2 +/- 4.3 years) patients (aged 54.8 +/- 12.0 years, 45% men) with chronic isolated severe MR who underwent ETT before mitral valve surgery to test the hypotheses that exercise duration predicts long-term postoperative survival and persistent symptoms within 2 years after operation. During follow-up, 11 patients died; of these, 8 had persistent symptoms. Among patients who exercised >7 minutes, average annual postoperative all-cause and cardiovascular mortality risks were 0.75% (both endpoints) versus 5.4% and 4.8%, respectively, versus those who exercised /=II) symptom persistence (p = 0.012), whereas other ETT, echocardiographic and clinical variables did not (NS, all). In conclusion, among patients who undergo surgery for chronic nonischemic mitral regurgitation, preoperative exercise duration, unlike many commonly used descriptors, is useful for predicting postoperative mortality and symptom persistence. Future research should determine whether interventions to improve exercise tolerance before mitral valve surgery can modify these postoperative outcomes.

Total occlusion of the left main coronary artery predominantly presents with recurrent angina or myocardial infarction. Long-term survival and myocardial function depends on the well-developed right to left collaterals. We report a case of a 46-year-old man who was referred because of incidental finding of low ejection fraction during work-up for syncope 5 months prior. The patient denied any recurrence or any other symptom after that episode and claimed an unchanged exercise capacity. He had hypertension, hyperlipidemia, and history of 15-pack/year smoking. Except for class II morbid obesity, he had completely normal vital signs, physical examination, and lab tests on admission. The echocardiogram was suggestive of previous anterior wall myocardial infarction and demonstrated a low left ventricle ejection fraction with diffuse hypokinesis of the left ventricle. The patient underwent cardiac catheterization, which revealed total occlusion of the left main coronary artery, dominant right coronary artery with a 95% stenosis in the proximal segment, and collaterals from the right to the left coronary arteries. The patient was immediately referred for coronary artery bypass surgery. This case demonstrates the power of collateral circulation in protecting the patient from symptoms and death despite total occlusion of the left main coronary artery and severe stenosis of the proximal right coronary artery.