Difference Between Systolic and Diastolic Heart Failure

Diastolic heart failure is a condition where the ventricles do not fill adequately under normal pressures and volumes. Systolic heart failure is a condition where the heart does not pump well. Both conditions are on the rise. According to the world health organization, the recent pandemic rise of ischemic heart diseases and heart failure are due to alcohol, smoking, and sedentary lifestyle. This article will talk about both conditions in detail, highlighting their clinical features, symptoms, causes, investigation and diagnosis, prognosis, treatment they require, and the differences between systolic and diastolic heart failure.

Diastolic Heart Failure

Diastolic heart failure is a condition where the ventricles do not fill adequately under normal pressures and volumes. Diastolic heart failure features a diminished function of one or both ventricles during diastole. There is poor relaxation of the ventricles and poor filling. High blood pressure, aortic valve obstruction, age, diabetes, constrictive pericarditis, amyloidosis, sarcoidosis, and fibrosis are known risk factors. In hypertension, left ventricle thickness increases to deal with higher blood pressures. Heart muscle thickens to pump more blood out when the aortic valve is narrow. Thicker muscle means smaller the end diastolic volume. There is less filling leading to poor output. Diastolic heart failure patients present with leg swelling, difficulty in breathing, abdominal distension and enlarged liver. ECG may show left ventricular hypertrophy.

Systolic Heart Failure

Systolic heart failure features diminished ability of the ventricles to contract during systole. It is a condition where the heart does not pump well. Heart chambers fill adequately during diastole, but it cannot eject blood into the aorta forcefully enough to maintain good blood pressures. Ischemic heart disease is the commonest cause. Heart muscle heals with a scar after a heart attack. This scar tissue cannot contract as well as the other parts of the heart. Patients with systolic heart failure present with poor exercise tolerance, chest pain, dizziness, lightheadedness, poor urine output, and cold peripheries. ECG may show ischemic changes.

Systolic vs Diastolic Heart Failure

• Old age, diabetes, ischemic heart diseases, and high blood pressure are known risk factors of both systolic and diastolic heart failure.

• Both conditions need the same investigations. Echocardiogram measures heart chamber sizes.

• Left ventricular mass increases in both conditions.

• Only a part of the end diastolic ventricular volume goes into the aorta during systole. In healthy individuals, it is more than 65%. Ejection fraction is normal in diastolic heart failure while it is low in systolic heart failure.

Angiography may be needed irrespective of the type of heart failure.

• Symptomatic systolic and diastolic heart failure have similar mortality rates.

• However, systolic heart failure is commoner than diastolic heart failure.

• High blood pressure is the commonest cause of diastolic heart failure while ischemia is the commonest cause of systolic heart failure.

• Left ventricle cavity size increases in systolic heart failure while it is normal or low in diastolic heart failure.

• Ventricular wall thickness increases in diastolic failure while it decreases in systolic failure.

• Poor contractile function is the main malfunction in systolic failure while excessive passive stiffness and poor relaxation are the main malfunctions in diastolic failure.

• Left ventricle dilates in systolic heart failure while it does not in diastolic heart failure unless there is associated ischemia.

• Many advances have been made in treating systolic heart failure while diastolic heart failure management remains almost the same.

• Chronic resynchronization with or without a defibrillator improves the prognosis of systolic heart failure while studies have not shown significant benefit of resynchronization in diastolic heart failure.

• Advanced systolic heart failure may also have features of poor filling (a component of diastolic failure) while diastolic heart failure does not have features of poor output (a component of systolic failure).


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