Ask The Doctors: October 2019
Q: I was recently evaluated for shortness of breath with exertion. My doctor said I have heart failure, but my heart is pumping normally. How is that possible?
A: Heart failure (HF) can be caused by a heart attack or similar event that impairs the heart's pumping function and reduces the amount of blood ejected with each beat (heart failure with reduced ejection fraction, or HFrEF). There is also a second form called heart failure with preserved ejection fraction (HFpEF). These patients typically suffer from heart failure symptoms, but their ejection fraction is normal. Morbidity and mortality are similar in both forms.
HFpEF can be caused by many processes, including scarring, stiffness, and infiltration or inflammation of the heart muscle. Heart muscle hypertrophy/thickening and stiffness may be stimulated by obesity, diabetes or hypertension. The heart performs less efficiently because it has to work harder to exert the extra pressure needed to eject blood. Patients with HFpEF tend to be older and often have hypertension, atrial fibrillation (AF), COPD or anemia.
To date, there is little convincing evidence from clinical trials that specific drug therapies reduce mortality. Treatment focuses on symptoms, using diuretics to manage fluid buildup and controlling contributing factors such as hypertension, coronary disease, anemia, COPD or AF. SGLT-2 inhibitors have been shown to reduce HF admissions, but not specifically in HFpEF. Trials are ongoing.
Some drugs used to treat HFrEF, including angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), spironolactone and sacubitril/valsartan, may also offer benefit, particularly in patients with EF in the lower range of the HFpEF spectrum. Exercise and diet have been shown to improve exercise respiratory parameters and function and are important elements of the treatment program.
Q: My 75-year-old father was diagnosed with heart failure due to amyloid in the heart. What is this? Can it be treated?
A: Until recently, cardiac amyloidosis was poorly understood and underdiagnosed. There were long delays between the first symptoms and diagnosis and a short time between diagnosis and death.
Amyloidosis is a relatively rare group of diseases characterized by the deposition of thread-like proteins called fibrils in tissues. The diagnosis is made by combining clinical, family and neurologic histories with lab tests for protein light chains, electrocardiography, echocardiography, MRI and nuclear scans, tissue biopsy and genetic testing.
Light-chain amyloidosis requires chemotherapy and other treatments, such as stem cell transplantation. The other major type, which is more likely to involve the heart and nerves, is transthyretin amyloidosis (ATTR). There are 2 major subtypes: genetic mutation (hereditary) and age-related (senile or wild-type). Many wild-type ATTR patients present with heart problems, usually heart failure with preserved ejection fraction (HFpEF). Up to 15% of patients with HFpEF may have amyloidosis.
Treatments for ATTR depend on type and may include liver transplantation to reduce TTR production, close follow-up and treatment of heart conduction abnormalities and supportive care. Genetic counseling for families with hereditary ATTR is advised. Drugs may be used to stabilize TTR (tafamidis) or stop the synthesis of TTR (patisiran).
Amyloid-associated heart failure requires tailored therapy, since drugs commonly used in HF that slow heart rate, e.g., beta-blockers, should be avoided. Diuretic doses need to be carefully adjusted. Since early diagnosis and differentiation of amyloid type greatly impact treatment choices and outcomes, referral to a heart center specializing in cardiac amyloidosis is recommended.