It is important to recognise underlying causes and precipitating factors of heart failure for its appropriate management. That would also help in prevention and treatment of heart failure. The causes could be broadly classified as those due to myocardial damage or volume overload or pressure overload or arrhythmias.
Myocardial Damage
Coronary artery disease (myocardial ischemia or infarction), myocarditis, cardiomyopathies could lead to myocardial dysfunction.
Volume Overload Conditions
Valvular diseases (e.g. aortic regurgitation, mitral regurgitation) and congenital heart diseases (e.g. ventricular septal defect, patent ductus arteriosus)
Pressure Overload Conditions
Hypertension, aortic stenosis, coarctation of aorta impose pressure overload on the heart.
Precipitating Causes of Heart Failure
In majority of the cases one is often able to identify a precipitating cause of heart failure.
Arrhythmias
Cardiac arrhythmias are common in patients with various types of heart diseases and may precipitate or worsen heart failure through several mechanisms:
a) Tachyarrhythmias reduce ventricular filling, increase myocardial oxygen demand and in patients with coronary artery disease aggravate myocardial ischemia. This results in both systolic and diastolic dysfunction. If persistent it may cause a reversible cardiomyopathy (tachyarrhythmias induced cardiomyopathy).
b) Marked bradycardia in patients with underlying heart disease depresses cardiac output.
c) Atrioventricular dissociation results in loss of atrial boost leading to impaired ventricular filling, lower cardiac output and raised atrial pressure.
d) Abnormal intraventricular conduction impairs myocardial performance due to asynchronous ventricular contraction.