371 - High Output Heart Failure—A Reversible Cause Missed Again!

Abstract

Introduction: High output heart failure is a rare but often reversible condition in adults. Current guidelines do not suggest screening for high output in heart failure patients unless it is suggested by history or physical exam. We describe here an unusual case of heart failure secondary to renal A-V malformation discovered incidentally. Case Presentation: A 74 year old woman with hypertension, hyperlipidemia, and chronic systolic heart failure due to nonischemic cardiomyopathy diagnosed over a year ago presented with acute exacerbation to the emergency department. Her echocardiogram revealed dilated cardiomyopathy with ejection fraction of 30%. During work up for her abdominal pain at this hospitalization, an ultrasound and a CT scan revealed an incidental large cavernous right renal arteriovenous malformation with a dilated right renal artery (2.3 cm) feeding into a nidus of vessels. Right heart catheterization revealed cardiac output of 8.3 L/min. In absence of any other reason for her high output heart failure, vascular surgery was consulted and the renal A-V malformation was successfully embolized. Three months later, the patient was seen at a follow up visit with complete resolution of her symptoms. At that visit, the echocardiogram revealed normalization of EF (55–60%) and chamber sizes. Cardiac output measured by echocardiography was 5.2 L/min. Discussion: Over 25% of heart failure patients have idiopathic cardiomyopathy. Attempts to find a reversible cause are vital as otherwise the prognosis is poor with high morbidity and mortality. Cardiac output can be measured noninvasively during a routine echocardiography, avoiding need for an invasive test such as cardiac catheterization. In cases of idiopathic cardiomyopathy leading to heart failure, detecting high output through a noninvasive test may lead to establishment of a reversible cause. Some of the causes of high output heart failure are A-V fistulas, anemia, hyperthyroidism, and sepsis. Beriberi can also cause high output heart failure but it is rare in adults in developed countries. Echocardiography can help not only in diagnosis but also in follow up after treatment to monitor change in cardiac output. Thus a routine noninvasive test, if used properly, could provide significant information that can alter the course of the patient's disease. Conclusion: In cases of idiopathic heart failure, measuring cardiac output through echocardiography is safe and inexpensive. Detection of high cardiac output should ignite the search for a potentially reversible etiology. Echocardiography can also be used to monitor efficacy of treatment.