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Did you know?
The human heart is the size of a large, closed fist.
The human heart beats about 60 to 80 times per minute, about 1,00,000 times a day and around 3 billion beats in a lifetime.
A healthy heart pumps around 5.7 litres of blood in a day.
The heart is situated in the centre of the chest and points slightly towards left.
The name of the Bollywood movie 'Dil Dhadakne Do' (if taken literally) seems to suggest that ability of the human heart to beat is a conscious and voluntary decision. We are able to relax our heart beats through slow and deep breathing (medication) and spike them through high intensity exercise or due to an increase in adrenalin which is basically our fight or flight mode. The universal truth, however, remains that rather like breathing from our first breath to our last, the thoroughly critical ability of the beating of our heart remains involuntary
According to Henry Grey's book 'Anatomy of the Human Body', the human heart weighs between 280 to 340 g in men and 230 to 280 grams in women. The human heart has four chambers - the two upper chambers called atria and the two lower chambers are called ventricles.
The right atrium and the right ventricle (together called the right heart) and the left atrium and the left ventricle (together called the left heart) are separated by a thin muscular membrane called septum. The right atrium is larger than the left atrium.
But the left atrium has thicker walls.
The sinoatrial node is situated in the upper part of the wall of the right atrium. This is the heart's natural pace maker as it produces the electrical impulses that allow the heart to beat.
The sequence of the blood flow through the human heart is as follows:
The right atrium receives blood from the entire body (except lungs).
Blood flows from the right atrium into the right ventricle.
The right ventricle pumps the blood to the lungs to be re-oxygenated.
The left atrium receives blood from the lungs.
Blood flows from the left atrium to the left ventricle
The left ventricle pumps the blood throughout the body through the aorta which is the largest artery in the body.
The atria and the ventricles are connected by the atrioventricular (AV) valves. A valve (pulmonary semi-lunar valve) separates the right ventricle from the pulmonary artery. Another valve (aortic valve) separates the left ventricle from the aorta. The valves ensure blood flow in one direction only.
The entire heart is covered by a sac called the pericardium. This sac has two walls which serve to protect the heart from harm. The pericardial fluid, which runs between these two walls, lubricates the heart while it pumps and also insulates it from the movement of the lungs and diaphragm.
The heart's outer wall consists of:
Epicardium - outermost wall layer which is also inner wall of the pericardium.
Myocardium - middle layer which comprises the muscle that contract.
Endocardium - inner layer containing the lining that contacts the blood.
The human heart is an extraordinary organ made up of muscles whose function is to pump fresh blood full of oxygen and nutrients to the tissues in the entire body. It takes in less oxygenated blood through the veins and delivers it to the lungs where the blood is oxygenated. This nutritious blood is then pumped into the various arteries to supply the body.
Once the oxygenated blood leaves the heart through the aorta, another set of arteries brings oxygenated and nutrient-rich blood to nourish the heart muscles to enable them to function.
The four primary coronary arteries are:
right main coronary artery
left main coronary artery
left circumflex artery
left anterior descending artery
If either of these arteries is blocked then it can result in a heart attack or damage to the muscle of the heart. Lack of adequate blood supply starves the heart of oxygen and the vital nutrients. This can cause chest pain (angina). If the blood supply to a portion of the heart muscle stops entirely or if the heart needs more energy than it is receiving, a heart attack (injury to the heart muscle) may occur.
Sometimes accumulated plaque (cholesterol deposits in the arteries) breaks down causing a blood clot which may block blood supply to the heart muscle. This could cause a heart attack.
A heart attack is distinct from cardiac arrest. A heart attack results because of lack of blood flow to the heart. Cardiac arrest is caused by a sudden loss of heart function due to problems in the electric impulses affecting the heart's rhythm. A heart attack could lead to cardiac arrest.
Heart disease is amongst the most dreaded complications of Diabetes. People with Diabetes require specialised care to prevent, diagnose and treat heart disease. High blood glucose levels (Diabetes) and hypertension (high blood pressure) increase the risk of heart failure. Other factors like obesity, smoking and high blood cholesterol increase risk of heart failure in people with Diabetes.
Heart failure usually develops gradually when blood vessels in the heart become weak. Their reduced ability to pump blood causes blood and fluid build-up and congestion. Heart muscles thicken or enlarge to compensate the declining pumping action, which further weakens them. Symptoms of heart failure include shortness of breath, persistent cough, fatigue, weight gain, chest pain, swelling of the feet, ankles and legs.
Silent heart attacks have either no symptoms or minimal symptoms or unrecognized symptoms. Uncontrolled diabetes is associated with inflammation of the inner lining of the arteries leading to damage and blockage of the artery resulting in heart attack. But unlike people without Diabetes, people with Diabetes may have such 'attacks' without any symptoms. When missed, the condition may lead to a major attack- which then is obviously symptomatic or even fatal.
To lower the risk of heart failure, managing blood sugar level is important. Lifestyle modification which includes cessation of smoking, maintaining a healthy weight, abstaining or limiting alcohol intake, reducing salt and fat in the diet, regularly exercising and taking prescribed medication is important to maintain heart health.
Additionally, people with Diabetes are advised to undergo annual tests like ECG and stress test to avail timely medical intervention, if required, to avoid heart failure. In case people with Diabetes are detected to have blockages in their blood vessels, relieving them by angioplasty (it is a minimally invasive heart procedure to widen the blocked arteries or veins due to plaque build- up) may also protect their heart.
An important part of taking care of yourself is keeping your blood pressure under control. High blood pressure - also called hypertension - raises your risk of heart attack, stroke, eye problems and kidney disease. As many as 2 out of 3 adults with Diabetes have high blood pressure.
Blood pressure is the force of blood flow inside your blood vessels. When your blood moves through your vessels with too much force, you have high blood pressure. Your heart has to work harder when blood pressure is high and your risk for Diabetes problems goes up. BP higher than 130/90 mm Hg usually is considered elevated and medical intervention is recommended.
It is a blood test that can measure the amount of cholesterol and triglycerides in your blood. People with Diabetes are advised annual testing of cholesterol levels.
Electrocardiography (ECG) is the process of recording the electrical activity of the heart by placing electrodes on the body. The electrocardiogram can measure the rate and rhythm of the heartbeat, as well as provide indirect evidence of blood flow to the heart muscle.
An echocardiogram is a test that uses sound waves to create pictures of the heart. Echo also can pinpoint
heart muscle that isn't contracting well because of poor blood flow or injury
blood clots in the heart
fluid build-up in the pericardium (the sac around the heart)
structural abnormalities in the heart valves
problems with the aorta (The aorta is the main artery that carries oxygen-rich blood from your heart to your body)
the flow of blood through your heart's chambers and valves (in case of Doppler echocardiogram)
Stress tests are tests performed to determine the amount of stress that your heart can manage before developing either an abnormal rhythm or evidence of ischemia (lack of blood flow to the heart muscle). The most commonly performed stress test is the tread mill exercise stress test which detects whether adequate blood supply is reaching your heart during a stress inducing event.
Angiography, a diagnostic procedure, uses a special dye and x-rays to detect how many blood vessels are blocked and the location and severity of the blockages.
Angioplasty, a corrective procedure, opens narrowed or blocked blood vessels. The surgeon inflates the narrowed blood vessel to widen it and improve blood flow. A stent (a small, metal mesh tube) is often placed during or immediately after angioplasty to prevent the artery from closing up again.
Cardiac bypass, also known as coronary artery bypass graft (CABG), requires a catheter be used to displace or cutting away the plaque attached to the artery walls and improve blood flow. Sometimes one or more stents (wire mesh) are inserted into the artery to repair any structural damage and allow blood flow.
