What makes the Heart cringe in Coronary Artery Disease (CAD)?
The heart is a unique muscular pump that beats for the entire life of an individual without a break or rest. This continued activity requires a constant supply of ‘fuel’ or oxygen rich blood. The fuel is supplied by blood flowing through two tiny coronary arteries that are first to take off from the main artery – Aorta that carries oxygenated blood from the main chamber of the left heart (Left Ventricle) to be distributed to all organs, far and near. The requirement of oxygen varies with the level of physical activity. Any increase in heart rate and blood pressure results in increased demand of oxygen like on brisk walking, jogging or a workout. Excitement and stress too have a similar effect. As the heart beats more vigorously blood flowing through the coronary arteries increase, it is reset to normal level once the demand is over. This demand and supply relationship is crucial to understand the symptoms and the treatment of coronary artery disease.
Demand and Supply
There are three major coronary arteries supplying the front and the back of the heart. While the Right Coronary Artery (RCA) supplies the blood to the right side of the heart, the left side has two major sources of supply arising from Left Main Coronary Artery (LMCA). One of these two is Left Anterior Descending artery (LAD) that supplies the front of the left heart while the Circumflex artery (Cx) caters to the back of the left ventricle. These three arteries have smaller off shoots reaching every nook and corner of the heart muscle. Blockages in one or more arteries lead to Coronary Artery Disease (CAD).
What are Blockages?
The coronary arteries become thickened with age, high blood pressure or with deposit of fats (Cholesterol) in the lining or the wall of the vessels leading to otherwise smooth lining becoming irregular and ulcerated. Recurrent episodes of injury and healing with further deposit of blood cells and fats (Atheroma) result in narrowing of the lumen of the affected artery. Progressive narrowing of the artery reduces the blood supply to the affected heart muscle. This may go unnoticed in individuals with desk jobs or sedentary life style and manifest only during times of unaccustomed activity or strenuous exercise. However once the narrowing becomes critical the blood flow is significantly compromised unable to meet even the usual demand. The heart muscle thus starved of oxygen and unable to carry on its function ‘cries out’, manifested as chest pain called ‘Angina’. This is similar to muscle cramps in the calf muscles after unaccustomed exercise. If the already narrowed artery were to choke completely either by a plaque or small blood clot, the area of heart muscle supplied by it ‘dies’ resulting in ‘heart attack’ or Myocardial Infarction (MI).
6 typical presentations of CAD
• Chest Pain or Angina
• Chest discomfort, Heart Burn, Shortness of Breath
• Silent Ischemia
• Easy Fatigability or Tiredness
• Heart Attack or Myocardial Infarction
• Sudden Death
Coronary artery disease or ischemic heart disease can severely limit the physical activity. This limitation makes the person seek medical attention. The intensity of symptoms depends upon severity of narrowing, number of arteries involved, degree of the blockages along with presence or absence of other risk factors and the life style of the affected individuals- very active to passive.
Sometimes there may not be any Angina or chest pain. Person may only experience fatigue or shortness of breath. Heart attack may be the first symptom landing one straight in the Emergency Room without any warning. This is called Acute Coronary Syndrome.
It is not unusual to hear of cardiac arrest in an otherwise healthy individual. Sometimes the heart attacks have struck people in twenties and even some young athletes on the sport fields. CAD may present as ‘Sudden Death’ that is invariably due to electric instability or ventricular fibrillation. It is also possible that some minor symptoms were ignored in the past.
In a classical case angina or pain in chest is brought about by unusual activity as one of the commonest clinical presentations. This is also referred to as ‘Stable Angina’. This can progress to angina at rest when even the basic resting needs of the heart are not met and the narrowing has progressed to critical level resulting in ‘Unstable Angina’. The classical pain that radiates to left arm, jaw or the neck may not be always present. It may very often be only a mild chest discomfort, uneasy sensation behind the sternum or even a heart burn that many a times passes off as indigestion. Usually symptoms may occur temporarily for a few minutes on exercise or emotional stress and settle down after a little rest or cooling down. Chest pain may also be absent in individuals with long standing Diabetes Mellitus.
Good News is that very effective remedies are available to bail out the individuals suffering from heart disease (CAD) in a most efficient and reliable way.
We will talk about these in our next conversation….
Caution: What is described above is essentially general information. Individuals having doubts or questions about their heart status should consult their personal physician.
Written byDr Ratna Magotra
Dr. Ratna Magotra is former Professor and Chief Cardio-Thoracic Surgery, KEM Hospital, Mumbai. She’s currently Consultant Cardiac Surgeon at Smt. S R Mehta & Sir K P Cardiac Institute, Mumbai, Trustee and Honorary Director of Cardiac Services, Gram Seva Trust, Kharel (Navsari District, Gujarat) working with marginalised communities. Trustee, Public Concern for Governance Trust, Mumbai.