Heart Failure

February is Heart Month and today I am going to be talking about one of the most common cardiovascular diseases, heart failure.

Heart failure describes a condition where the heart fails to either pump blood to the body organs (known as systolic heart failure) and/or fails to relax and empty the blood coming from the organs back to the heart (known as diastolic heart failure). Patients can have one of these kinds of heart failure or both. It is estimated that 26 million people worldwide suffer from heart failure. It is a major cause of morbidity and mortality, especially in the older population. Heart failure symptoms include shortness of breath, especially when exercising or lying flat, edema (mainly in the legs), fatigue, weight gain, cough, cognitive changes and chest pain. Heart failure symptom severity is graded according to the New York Heart Association classification (which includes NYHA class 1 to 4). The higher the class, the worse the long term prognosis. Classifying heart failure can be confusing but a recent universal definition is worth mentioning. Heart failure (HF) stages are now classified as at risk of HF, pre-HF, HF and advanced HF. According to the ejection fraction, HF can also be classified as HF with reduced rejection fraction (<40%), mildly reduced ejection fraction (40-50%) and preserved ejection fraction (>50%). The new definition includes an improved ejection fraction category, defined as an improvement of ejection fraction by 10% or more from baseline. These definitions are important as they determine prognosis and treatment strategies.

So, what causes heart failure? Hypertension, coronary artery disease, valvular heart disease, advanced kidney disease, and heart rhythm disturbances are common causes. Infiltrative, familial and hypertrophic cardiomyopathies are less common etiologies of heart failure

Diagnosing heart failure usually starts with a good history and physical exam. Physical exam findings include signs of congestion such as bilateral pitting edema, lung crackles and an elevated jugular venous pressure. These all indicate the inability of the heart to relax appropriately, resulting in elevated cardiac filling pressures. Other signs on physical exam such as cold extremities, reduced capillary filling time, altered mental status and low blood pressure are signs of reduced cardiac output, which can lead to multiorgan failure. It is important to recognize these constellations of findings because they warrant emergent treatment. Blood tests such as comprehensive metabolic panel can help determine if heart failure has caused organ damage. Other blood tests such as Pro-BNP and troponin levels can be used for diagnosis and prognosis. Further cardiac testing is needed to determine the degree of cardiac damage and identify the etiology. An echocardiogram is needed to assess cardiac function (ejection fraction, EF) and look for structural abnormalities such as valvular disease. Other tests such as PET scan, cardiac MRI or CT and heart catheterization may also be needed to determine the etiology of heart failure.

Lastly, I want to briefly discuss how we manage heat failure. First, we need to identify the etiology of heart failure and try to reverse it. For example, coronary artery disease may require stenting or coronary bypass grafting. Valvular heart disease may require surgery or transcatheter interventions. Arrhythmias such as atrial flutter may require an ablation. Patients with amyloidosis may be candidates for a new medication called Tafamadis.

If the heart failure becomes chronic, a comprehensive approach is needed to improve patient symptoms and heart function, reduce heart failure hospitalizations, and ultimately decrease mortality. First, adherence to healthy lifestyle choices is important and this includes significant changes in dietary habits (such as eating a healthy, low-salt diet) and quitting smoking. Physical exercise is also generally recommended. Second, guideline directed medical therapy is a cornerstone of HF treatment and is prescribed according to EF and heart failure stage and patients’ tolerance. For patients with reduced ejection fraction, there are four pillars of treatment. These include beta blockers, ACE-I or ARBs and their new cousin Neprilysin inhibitors, aldosterone antagonists and last but not least SGLT2-inhibitor diabetes drugs, which have been shown to benefit even patients without diabetes and those with a preserved ejection fraction. Other medications such as diuretics, ivabradine and digoxin are tailored to patient needs. Third, patients with heart failure may benefit from device therapies such as cardiac resynchronization therapy if they meet certain criteria such as a left bundle branch block with QRS >150 ms in width and cardiac contractility modulation therapy. Patients with heart failure are also susceptible to sudden cardiac death due to ventricular tachyarrhythmias and may be candidates for primary prevention defibrillator implantation if their ejection fraction is <35% or for secondary prevention if they have documented ventricular arrhythmias. Finally, end-stage heart failure may require advanced therapies with inotropes, left ventricular assist devices or a heart transplant. Please remember that heart failure is a complex disease and I would certainly recommend that you refer patients to a cardiologist or heart failure specialist.

References:

• ESC (European) guidelines https://academic.oup.com/eurheartj/article/42/36/3599/6358045
• ACC/AHA/HFSA (American) guidelines https://www.ahajournals.org/doi/full/10.1161/CIR.0000000000000509
• New Universal Definition of Heart failure (https://www.onlinejcf.com/article/S1071-9164(21)00050-6/fulltext)

Patient information (Cleveland Clinic) https://my.clevelandclinic.org/health/diseases/17069-heart-failure-understanding-heart-failure