Your heart truly is amazing, precious, beautiful and alive.

It is a muscular pump that circulates your blood containing nutrients and oxygen (O2) to the entire body. The byproducts of life, like carbon dioxide (CO2) and metabolites are carried back to the heart in the venous blood. There are 4 chambers within the heart. The forward flow of blood between chambers and out from the heart is controlled by 4 heart valves.

A normal heartbeat is rhythmic and synchronized. The upper chamber (atrium) contracts to deliver blood to the relaxed lower chamber (ventricle). The ventricle then contracts to pump blood out of the heart.

There are 2 sides of the heart, right and left. Venous (deoxygenated) blood comes back from the body systems to the right atrium and flows through the tricuspid valve into the right ventricle. Blood is then pumped out of the heart by the right ventricle through the pulmonary valveinto both lungs via the pulmonary arteries. While the blood is distributed to the lungs CO2 is released and O2 is absorbed.

This newly oxygenated (red) blood then travels back to the heart in the pulmonary veins to the left atrium before traversing through the mitral valve into the left ventricle. The O2 enriched blood is then pumped out of the heart through the aortic valveby the left ventricle to distribute O2 and other nutrients to the body. This cycle repeats continuously to keep us alive.

Normal Heart: Every muscle (including the heart) requires O2 to contract. Blood rich in O2 is delivered to the heart by coronary arteries. Heart valves normally function as one way valves that allow blood to flow through them but do not allow blood to leak backward (regurgitation). The valves open and close in a rhythmic synchronized manner “lub-dub” and mirror the rhythmic synchronized contractions of the upper and lower heart chambers. An electrical impulse is the origin of the rhythmic contractions. A signal begins in the atria and stimulates atrial contraction. The signal is conducted to the ventricle which stimulates ventricular contraction. The cycle repeats causing rhythmic synchronized heart contractions that create ‘the pulse‘ of circulation.

Abnormal Heart: If the O2 required for heart muscle contractility (O2 demand) exceeds the O2 supplied by the coronary arteries a “supply-demand” imbalance occurs. In this scenario, the heart muscle cramps and a person typically experiences chest pain also known as angina. The pain may radiate to the neck or jaw or down either arm or through to the back. There may also be associated nausea and vomiting, sweating and shortness of breath. If a coronary artery is narrowed by plaque (cholesterol buildup) and blood flow to a muscle territory is limited then the above symptoms may develop. If interruption of blood flow lasts more than a few minutes then the heart muscle territory is damaged causing a myocardial infarction (MI) also known as a heart attack.

Similarly, if the heart muscle has to pump blood through a narrowed valve (stenosis) an increased strength of muscle contraction is required to create enough pressure to push the blood through the smaller valve. The increased strength of muscle contraction, however, requires more O2 and if O2 supplied to the muscle is inadequate then this “supply-demand” imbalance will also cause angina and shortness of breath. Early on, symptoms occur with exertion and then progress to occur with minimal to no exertion. The time frame during which the symptoms may progress varies widely.

‘Congestive heart failure’ occurs when either the heart muscle is chronically weakened from previous heart attacks or valvular disease (stenosis or regurgitation) decreases the effective forward flow of blood through the heart. The overall decrease in forward flow of blood then results in a congestion of blood in the lungs wherein patients feel shortness of breath. Early on in disease progression shortness of breath may occur with moderate or heavy exertion but as disease worsens symptoms may occur with little to no activity. The time frame during which symptoms may progress varies widely.

If the impulse conduction through the heart is abnormal then a rhythm disturbance (arrythmia) may result in a fast, slow or irregular heart rate. Heart rate disturbances can lead to ineffective heart contractions which may decrease the overall pulsatile flow of blood in the circulation. Palpitations, low blood pressure, dizziness, fainting, shortness of breath and easy fatigue are common symptoms of heart rhythm disturbances.

YOUR HEART … It is truly amazing that your heart, a muscular organ slightly bigger than your fist, can keep your entire body alive. The video above shows the beauty of each heartbeat. We must take care of our precious heart and recognize some important signs of heart disease described above. Visit a doctor and tell them if you or anyone you know is experiencing any of the above symptoms.