Heart Failure:Causes, Types, and Treatment
This is a common clinical syndrome identified by the presence of current or prior characteristic symptoms, such as shortness of breath and fatigue, and evidence of cardiac dysfunction as a cause of these symptoms of Heart Failure
About Heart Failure
From a hemodynamic perspective, heart failure is a disorder in which the heart cannot pump blood to the body at a rate keeping pace with its needs. Patients with heart failure may or may not have associated physical signs, such as those related to fluid retention.
Conditions for Heart Failure
Heart failure is caused by a number of conditions, including left ventricular dysfunction, right ventricular dysfunction, valvular heart disease, pericardial disease, obstructive lesions in the heart or great vessels, or high-output heart failure.
Heart failure caused by left ventricular dysfunction is commonly categorized according to left ventricular ejection fraction, commonly as assessed by the echocardiogram:
1- Left ventricular ejection fraction equal to or less than 40 percent on the echocardiogram is known as heart failure with reduced ejection fraction.
2- Left ventricular ejection fraction of 41 to 49 percent on the echocardiogram is heart failure with mid-range ejection fraction.
3- Left ventricular ejection fraction equal to or more than 50 percent on the echocardiogram is heart failure with preserved ejection fraction.
This can also be due to diseases of the muscle of the heart, referred to as cardiomyopathy, which can be either restrictive, hypertrophic, or due to noncompaction. The commonest causes of heart failure are left-sided, meaning that it is caused by diseases affecting the left ventricle.
Heart failure is labeled as right-sided when it is caused by right heart conditions, for example, pulmonary hypertension, pulmonic valve dysfunction, or tricuspid valve dysfunction. Left heart failure and right heart failure may each occur separately or concurrently.
Left heart failure
Left heart failure is a common cause of right heart failure and most patients with right heart failure have some element of left heart failure. Symptoms of heart failure include those due to excess fluid accumulation and include shortness of breath on exertion, shortness of breath when lying flat, leg swelling, pain from liver congestion, and abdominal discomfort due to distention from fluid accumulation in the abdominal cavity.
Symptoms also occur due to a reduction in cardiac output like fatigue and weakness, and these are most pronounced with exertion. The physical examination can provide evidence of the presence and extent of cardiac filling pressure elevation, right-sided failure, ventricular enlargement, pulmonary hypertension, and reduction in cardiac output.
Patients with mild or moderate heart failure may appear completely normal on physical examination, with normal vital signs. However, many patients with normal cardiac output at rest have the inability to increase the cardiac output during exercise without excessive increase in filling pressures, resulting in exertional fatigue and intolerance.
Right-sided signs with fluid overload are often the presenting sign. In contrast, patients with advanced heart failure may show evidence of decreased tissue perfusion caused by a major decline in cardiac output.
Four key findings that suggest a greater severity of cardiac dysfunction even at a steady state include:
1- resting increase in heart rate, medically known as sinus tachycardia,
2- narrow pulse pressure,
4- peripheral vasoconstriction manifest by cool, pale, and sometimes cyanotic extremities.
Major Manifestations of volume overload in Patients with Heart Failure
There are three major manifestations of volume overload in patients with heart failure:
pulmonary congestion, peripheral edema, and elevated jugular venous pressure.
●Pulmonary congestion manifests as crepitations on auscultating the lungs and is more prominent in acute or subacute heart failure.
●Right-sided failure may be manifested as peripheral edema with swelling of the legs, which is more prominent when the patient has been upright. It can also manifest as fluid in the abdominal cavity referred to as ascites, in addition to fluid accumulation in the scrotum.
●Elevated jugular venous pressure is usually present if peripheral edema is due to heart failure.
Tests are Performed for the Evaluation of Heart Failure
The following tests are performed for the evaluation of heart failure:
1- Electrocardiogram — Most patients with heart failure with reduced left ventricular ejection fraction have a significant abnormality on an electrocardiogram, the ECG. A normal ECG makes left ventricular heart failure unlikely. In contrast, patients with heart failure with preserved ejection fraction, HFpEF, commonly display a normal 12-lead ECG.
2- Blood tests should include:
●Natriuretic peptide levels. This provides evidence as to whether heart failure is present, as levels are elevated in heart failure patients.
●Cardiac troponin T or I, to evaluate whether the acute decompensated heart failure is due to a heart attack.
●A complete blood count, which may suggest concurrent or alternate conditions. Anemia or infection can exacerbate pre-existing heart failure.
●Kidney function test to detect renal impairment which might be caused by and/or contribute to heart failure exacerbation.
●Liver function tests, abnormality of which may reflect liver congestion as a result of heart failure.
3- Chest X-Ray — Findings suggestive of heart failure include cardiomegaly, which is an enlarged heart, with a heart-to-thoracic width ratio above 50 percent. Other chest X-Ray findings would include pulmonary venous congestion, and fluid in the cavity of the linings of the lung, known as pleural effusion.
4- Echocardiography is needed to assess the right and left ventricular systolic function, and valve abnormalities in addition to an assessment of the pulmonary pressure.
In the case of Diastolic Dysfunction
It is also needed to assess whether the left ventricular function is reduced, mid-level, or may be preserved as in the case of diastolic dysfunction. Treatment of heart failure depends on the cause of heart failure, and whether the heart failure is due to reduced ejection fraction, mid-range ejection fraction, or preserved ejection fraction. Generally, the goals of therapy for heart failure are to reduce symptoms, improve health-related quality of life and functional status, decrease the rate of hospitalization, and reduce death.
Treatment of Heart Failure
In addition to treating the cause of heart failure and associated conditions, treatment of heart failure should include monitoring and preventative care, care coordination, education and support for heart failure self-management including lifestyle modification and daily monitoring, medication therapy, cardiac rehabilitation, palliative care, device therapy including cardiac resynchronization therapy, implantable cardioverter defibrillator.
In advanced heart failure, mechanical circulatory support devices, like left ventricular assist devices, and cardiac transplantation, should be considered. Medication therapy commonly used for heart failure includes diuretic therapy, angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, beta-blockers, vasodilators, and other medications.