- Reduced Blood Supply to the heart (Ischemic Heart Disease / Coronary Artery Disease) : Due to various reasons, fat gets deposited on the inside wall of coronary arteries. This process is like salting of water tubes. When this leads the critical narrowing of the inner diameter of arteries, the heart does not receive adequate blood. This results in chest heaviness or pain (angina) when one exerts.
Sometimes blood gets thickened and clotted. This leads to sudden occlusion of the artery with subsequent cessation of blood supply to a part of the heart. This event is known as a heart attack (acute myocardial infarction / acute coronary syndrome).
- Deranged Structure or Function of the Valves (Valvular Heart Disease) : This can happen due to various reasons. Rheumatic fever is the commonest cause for valve disease in India. Heart attack, infection of the valve, faulty formation during intrauterine life, wear and tear process due to aging are few other important causes leading to valve disease. Diseased valve can either get narrowed and may not open as well (stenosis) or it does not close perfectly allowing backflow of blood (regurgitation).
- Defects in the Structure of the Heart by Birth (Congenital Heart Disease) : Some newborns have defects in valves or septum or great vessels. Narrowed valve (Valvular Stenosis), hole in the heart (ventricular of Atrial Septal Defect), persistence of an extra artery allowing mixing of pure and impure blood (Patent Ductus Arteriosus), deranged attachment of arteries carrying pure and impure blood (Transposition of the Great Arteries), combinations of various defects. Breathlessness, recurrent respiratory tract infections, bluish discoloration of the body, delayed milestones of mental and physical growth and development are few common features seen in such children.
- Weakened Muscles of the Heart (Ventricular Dysfunction / Heart Failure) : This leads to reduced ability of the heart to pump blood. The most important reason for this is a heart attack or coronary artery disease. Valvular disease, congenital disease, some viral infections, diabetes or thyroid disease, vitamin deficiencies, and uncommonly pregnancy also can lead to heart failure. This is a potentially serious illness. Breathlessness on exertion or at rest, swelling of legs, undue fatigue, giddiness, etc. are few important symptoms.
- Fluid Collection Surrounding the Heart (Pericardial Disease) : Two thin layers surrounding the heart help to reduce friction while heart contracts and to some extent, protect the heart. Due to various reasons like infection with tuberculosis / virus, rheumatic fever, thyroid disease, some cancerous conditions, kidney failure, etc,. these layers may get inflamed and accumulate fluid.If not treated in time, this can lead to loss of elasticity (Constrictive Pericarditis) and subsequent compression of the heart.
- Abnormal Heart Rhythm (Tachyarrhythmia / Bradyarrhythmia) : The human beats 60-100 times per minute. Various factors like age, different mental and physical conditions, regular habit of exercising, etc. help to decide this basic heart rate. With aging heart rate decreases, while during exertion or stress heart rate increases. Many illnesses of body have their effects on the heart rate. That is why a Doctor would see your pulse when you go to a Doctor for any problem.
In some cases, heart rate increases to 170-300 / minute. Atrial fibrillation (AF), Ventricular Tachycardia (VT) or Supraventricular Tachycardia (SVT) are few such examples. Giddiness, chest heaviness, breathlessness, low feeling, palpitations (feeling of own heartbeats), unconsciousness, etc. are few manifestations. It may lead to death in some cases if not treated in time.
In some cases, heart rate may drop down to 25-40 / minute. Complete heart block (CHB) and sick sinus node (SSN) are few such conditions. Giddiness, breathlessness, fatigue, unconsciousness and even death can be manifestations.
The most commonly observed disease amongst the above mentioned diseases is – difficulty in supply of blood to the heart.