Congestive heart failure: Clinical sciences

Congestive heart failure, CHF, or the newer term, advanced heart failure, is a condition that occurs when the heart cannot pump or fill properly, leading to fluid accumulation in the lungs and other body tissues. It is a leading cause of morbidity and mortality worldwide. Based on the side of the heart that is affected, CHF can be classified as right-sided or left-sided heart failure.

Alright, the first thing to do when assessing a patient with signs and symptoms suggestive of CHF is to perform an ABCDE assessment to determine if they are stable or unstable. If the patient is unstable, stabilize their airway, breathing, and circulation, which might require intubation. Additionally, obtain IV access, administer supplemental oxygen, and put your patient on continuous vital sign monitoring.

OK, now that you’re done with acute management, obtain a focused history and physical exam, and order imaging, like Chest X-ray. History typically reveals fatigue, shortness of breath, dyspnea on exertion, orthopnea, and paroxysmal nocturnal dyspnea. On the flip side, a physical exam commonly reveals conversational dyspnea, rales, S3 heart sound, bilateral lower extremity edema, and jugular venous distention. Finally, a chest X-ray might show an enlarged cardiac silhouette and evidence of pulmonary congestion, such as a “batwing” or “butterfly” appearance from alveolar edema and Kerley B lines from interstitial edema.

Now, these findings should make you think of acute decompensated heart failure with pulmonary edema, so order B-type natriuretic peptide, or BNP for short; ECG; and a transthoracic echocardiogram, or TTE. BNP greater than 400; ECG findings associated with arrhythmias or ischemia, as well as TTE findings of ventricular dysfunction and valve abnormalities support the diagnosis of acute decompensated heart failure with pulmonary edema.

Alright, let’s switch gears to treatment. First, treat the underlying cause whenever possible. For example, cardioversion for atrial fibrillation. Next, treat symptoms of pulmonary congestion with loop diuretics, like furosemide, and IV vasodilators, such as hydralazine and nitrates, or you may even need positive inotropes, like dobutamine. Here’s a high yield fact! Beta blockers should never be taken during acute decompensated heart failure, due to worsening congestion from their acute negative inotropic effects. However, they can be given once the patient becomes euvolemic.

Once you initiate the treatment, assess the patient’s response. If there’s an adequate response, continue the current treatment until you can transition them to outpatient management. But, don’t forget the importance of lifestyle modifications, such as limiting sodium and fluid intake, as well as optimizing their chronic heart failure therapy. However, if the response is inadequate and the patient is worsening, then you need to switch to advanced therapy. This might include procedures like ultrafiltration for diuresis; and circulatory support, like extracorporeal membrane oxygenation or ECMO as well as mechanical circulatory support or MCS such as a left ventricular assist device. If the patient still fails to improve, consider a cardiac transplant.

Now that unstable patients are taken care of, let’s go back to the ABCDE assessment and talk about stable ones. When it comes to stable individuals, your first step is to obtain a focused history and physical, which will help determine if the CHF is left- or right-sided.

In left heart failure or LHF, the patient commonly reports symptoms related to lung congestion, such as orthopnea, paroxysmal nocturnal dyspnea, shortness of breath, and dyspnea on exertion. There might be a past history of hypertension, cardiovascular disease, or valvular disease. Physical exam typically reveals elevated blood pressure, tachypnea, as well as conversational dyspnea, rales, and an S3 sound. At this point, you should suspect left-sided heart failure, so your next step is to obtain labs, like BNP and CMP, ECG, as well as imaging, such as chest X-ray.

Most often, labs might show an elevated BNP, normal AST and ALT, and normal BUN and creatinine, which indicates normal renal function, but keep in mind that some patients may develop abnormal liver and kidney function tests. Next, the ECG might demonstrate findings consistent with LHF such as left axis deviation, left atrial enlargement, and left ventricular hypertrophy; but also it might reveal precipitating factors, like ischemia. Lastly, the chest X-ray typically shows an enlarged cardiac silhouette and pulmonary vascular congestion. If you see these findings, you should suspect left-sided heart failure.

Alright, now that we’ve diagnosed LHF, let’s determine the type of dysfunction. You can do this by using a TTE to calculate the left ventricle’s ejection fraction or EF for short. Now, if the EF is normal, meaning it’s equal to or greater than 50%, but there’s usually evidence of impaired relaxation, you can make the diagnosis of Heart Failure with preserved Ejection Fraction, or HFpEF for short, also known as diastolic or non-systolic heart failure.

Treatment includes minimizing risk factors and comorbidities, like optimizing blood pressure or treating arrhythmias; and medications to help control symptoms. Some important medications include diuretics like furosemide; as well as beta-blockers, such as carvedilol, to optimize blood pressure. Patients may also get either an ACE inhibitor or ACEi like lisinopril, an angiotensin receptor blocker or ARB like valsartan, or a combination angiotensin receptor/neprilysin inhibitor, or ARNI, which combines sacubitril and valsartan, and is actually preferred.

Mineralocorticoid receptor antagonists, or MRAs, like spironolactone, may also decrease hospitalization in patients with normal renal function and potassium levels. These medications are known as Renin angiotensin aldosterone system inhibitors, also called RAAS inhibitors. They help control blood pressure and reduce their hospitalization frequency. Finally, sodium-glucose cotransporter-2 inhibitors, or SGLT2i, such as dapagliflozin, help decrease mortality in HFpEF.

Once again, individuals with CHF require close follow-up to assess their response to therapy. If the patient’s response is adequate, continue the current treatment. However, if the response to therapy is inadequate, you should consider advanced therapy, such as ultrafiltration, circulatory support, or cardiac transplant.