Ep 173: A 48-Year-Old Woman with Heart Failure

In this installment of our Physiology at the Bedside series, we cover heart failure and the physiology behind its different types.

Read more on this topic in Harrison's.

Harrison's Principles of Internal Medicine, 22nd Edition

Transcript

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[Ms. Heidhausen] This is Katerina Heidhausen, executive editor of Harrison's Principles of Internal Medicine. Harrison's Podclass is brought to you by McGraw Hill's AccessMedicine, the online medical resource that delivers the latest content from the best minds in medicine. And now, on to the episode. 

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[Dr. Handy] Hi, everyone. Welcome back to Harrison's Podclass. We're your co-hosts. I'm Dr. Cathy Handy. 

[Dr. Wiener] And I'm Dr. Charlie Weiner, and we're joining you from the Johns Hopkins School of Medicine. 

[Dr. Handy] Welcome to today's episode, 48-year-old woman with heart failure. 

[Dr. Wiener] Cathy, today is number three in our Physiology at the Bedside series. 

[Dr. Handy] Great, tell me about our patient today. 

[Dr. Wiener] She's a 48-year-old woman with a 15-year history of scleroderma and hypertension. Her scleroderma is mild, only involving her hands and arms with some xerostomia. She's only required local therapies, and has not received any systemic treatment. Screening radiographs over that time have shown no interstitial lung disease. Her hypertension has required treatment with amlodipine, hydrochlorothiazide, and losartan. She has no known renal disease. Over the last three months, she's reported increasing dyspnea on exertion, orthopnea, and leg swelling. And over the last week, some shortness of breath at rest. 

[Dr. Handy] What's her physical exam, in particular, her cardiac and lung exams? 

[Dr. Wiener] She's overweight at baseline, but reports that her weight has gone up by eight pounds in the last couple weeks. She's afebrile. Her blood pressure is 155/90, heart rate is 90, respiratory rate is 16, and her resting room air saturation is 92%. Her neck veins are elevated. She has bilateral lower lung crackles, an S4, but no other murmurs, and two-plus pitting edema of her ankles and calves. Her hands have her baseline sclerodactyly, and no signs of poor perfusion. 

[Dr. Handy] So she has signs of heart failure with elevated neck veins, crackles, and edema, but with her scleroderma, she also could be having an acute pulmonary syndrome. Can I have some labs, particularly her renal function, and an echocardiogram? 

[Dr. Wiener] Yes. Her labs show that her creatinine is slightly elevated from her baseline of 1.1 up to 1.4, and her pro-BNP is elevated. Otherwise, the rest of the labs are okay. 

[Dr. Handy] That's reassuring. I don't think we're dealing with scleroderma renal crisis. What about the echo? 

[Dr. Wiener] Unfortunately, due to her body habitus, the echocardiogram is of poor quality, but the operator thinks there's pulmonary hypertension. She ends up undergoing cardiac catheterization, which shows no coronary artery disease, but abnormal hemodynamics. 

[Dr. Handy] Okay, so physiology at the bedside. Let's go through the measurements from the cath. 

[Dr. Wiener] Okay, let's start on the right side. Her right atrial pressure is 15, and her mean PA pressure is 30. 

[Dr. Handy] Those are both elevated. Typical right atrial pressure is about 5, and the mean PA pressure should be less than 15. How about her pulmonary capillary wedge pressure and cardiac index? 

[Dr. Wiener] Her pulmonary capillary wedge pressure is 20, and her cardiac index is 2.8. A ventriculogram shows an ejection fraction of 60% and no left ventricular dilation. 

[Dr. Handy] Okay, that's a high wedge pressure, too. The pulmonary capillary wedge pressure is an estimate of left atrial pressure and should be about 8 to 10. 

[Dr. Wiener] What about her cardiac index? 

[Dr. Handy] Her cardiac index is low normal, as typically it should be about 3. 

[Dr. Wiener] So to summarize, she has elevated right atrial, pulmonary artery, and left atrial pressures, with a normal ejection fraction and normal cardiac index. That's going to get us to our question. The question asks, which of the following is the most likely diagnosis in this patient? And the options are: A. chronic thromboembolic pulmonary hypertension; option B. heart failure with preserved ejection fraction, or HFpEF; C. heart failure with recovered ejection fraction, or HFrecEF; option D. is heart failure with reduced ejection fraction, or HFrEF; and option E. is pulmonary arterial hypertension. 

[Dr. Handy] This is a good question, because with scleroderma, she's at risk of all of these. The answer is B. she has heart failure with preserved ejection fraction. As soon as you see the elevated pulmonary capillary pressure, it's logical to conclude that the left atrial pressure is elevated. And in the absence of mitral valve disease, that's indicative of left ventricular failure. With the preserved or even elevated ejection fraction in our patient, you know this is HFpEF. 

[Dr. Wiener] Let's talk a little bit about heart failure because the landscape and terminology have changed over the last couple years. 

[Dr. Handy] Well first, heart failure is a clinical syndrome with symptoms and signs that result from any structural or functional impairment of ventricular filling, or ejection of blood from the heart, and it needs to be corroborated by some objective evidence of cardiogenic pulmonary or systemic congestion, or an elevated natriuretic peptide level. 

[Dr. Wiener] What about the terms cardiomyopathy and left ventricular dysfunction? 

[Dr. Handy] Cardiomyopathy and left ventricular dysfunction are more general terms that describe disorders of myocardial structure or function, which can lead to heart failure. Since we're talking about physiology at the bedside, heart failure has been defined as a syndrome characterized by elevated cardiac filling pressures, or inadequate peripheral oxygen delivery at rest, or during stress, and that's caused by cardiac dysfunction. 

[Dr. Wiener] That's simple, but now, as in our question, there's a whole bunch of new subtypes. 

[Dr. Handy] Yes, because the patient can have heart failure with preserved or reduced left ventricular function or ejection fraction. 

[Dr. Wiener] What is heart failure with recovered ejection fraction? 

[Dr. Handy] A subgroup of patients who are diagnosed with heart failure with a reduced EF, and treated with guideline-directed therapy have rapid or even gradual improvement in ejection fraction to the normal range. Those are the patients who are referred to as having heart failure with recovered ejection fraction. Predictors of this include younger age, shorter duration of heart failure, non-ischemic etiology, smaller ventricular volumes, and absence of myocardial fibrosis. Some examples where we might see this would be with myocarditis, or stress cardiomyopathy, or peripartum cardiomyopathy, or even after some exposures like chemotherapy, for example. 

[Dr. Wiener] So in those cases, how do patients do generally? 

[Dr. Handy] Well, despite recovery of EF, many patients may remain symptomatic due to persistent abnormalities in diastolic function or exercise-induced pulmonary hypertension or related comorbidities. In general, prognosis of patients with recovered EF is better than that of patients with either reduced EF or preserved EF. 

[Dr. Wiener] Okay, you already told us that you knew this patient had either HFpEF, or HFrEF, from the elevated left atrial pressure, but our patient also has pulmonary hypertension. Why? 

[Dr. Handy] With the elevated mean PA pressure and the elevated right atrial pressure, this patient has pulmonary hypertension. But remember that left heart failure of any phenotype is the most common cause of pulmonary hypertension, because the elevated left atrial pressure backs up through the pulmonary veins and pulmonary capillaries to the pulmonary artery. If severe enough, that elevated pulmonary arterial pressure can cause right ventricular dysfunction, and an elevated right atrial pressure, as in our patient. In the WHO classification, this is group two pulmonary hypertension. 

[Dr. Wiener] Great. So the teaching points in our case today are that heart failure is a clinical diagnosis with a range of phenotypes, and understanding the typical left and right heart filling pressures are essential to characterizing disease. An elevated left atrial pressure is generally diagnostic of left heart failure and is associated with group two pulmonary hypertension. 

[Dr. Handy] You can find this question and other questions like it on Harrison's Self-Review. And if you want to read more about the topic, you can check out the Harrison's chapter on heart failure, pathophysiology, and diagnosis. Visit the show notes for links to helpful resources, including related chapters and review questions from Harrison's, available exclusively on AccessMedicine. If you enjoyed this episode, please leave us a review, so we can reach more listeners just like you. Thanks so much for listening. 

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