The heart is a fascinating organ, even for us as doctors. Your understanding of the heart would be the fact that its main function is to pump blood and keep you alive. That’s on point. But, do you know how does it keep you alive?
It’s an amazing and complex mechanism and the more you read about it, the more awestruck you will be. Just like we need to kickstart a bike or a scooter, similarly, there is something that kickstarts your heart.
These electrical impulses are necessary for your heart to beat. In fact, if your heart is beating 60 times per minute, it means there are 60 electrical impulses triggering those heartbeats. These are critical for your heart to contract and pump blood that keeps you alive. Now, if there is electrical activity of the heart, there should be something triggering that, right? It’s called the sinus node and is controlled by the brain and other other circulating substances.
What happens next?
Once the sinus node of the heart generates this electrical activity, the electricity is distributed throughout the muscles of the heart through a specialised conduction system. Therefore, it is quite similar to a power generation and distribution system.
The heart has four chambers – two on top called Atria that collect blood and two on the bottom called ventricles that pump blood to the lungs and other parts of the body.
- Once the electrical activity of the heart begins, the right atrium collects oxygen-less blood from the rest of the body
- It then empties blood into the right ventricle, that promptly pumps it to the lungs.
- The lungs then add oxygen to the blood and remove carbon dioxide.
- Due to pressure difference blood flows from the lungs to the left atrium.
- The left atrium collects this oxygen fuelled blood and empties it into the left ventricle.
- The left ventricle pumps blood out to the rest of the body.
For this whole cycle to happen seamlessly, it’s essential that the electrical activity of the heart is in order. Since some time is needed for the upper chambers (atria) to empty blood into the lower chambers or ventricles, the electrical activity from the atria to the ventricles is delayed at a structure called Atrioventricular Node or AV Node. From the AV Node, electricity is conducted into the lower muscular chambers through two electric bundles called the Left Bundle (on the left side) and the Right Bundle (on the right side).
By now, you would have understood that these electrical activities of the heart are critical when it comes to your life. Just like an electrical equipment will shut down if the electrical supply to it is shut down, similarly, if there are no electrical impulses to the heart for 5 to 10 seconds, it would mean that the heart will stop beating for the same amount of time. In that case, you are likely to fall down unconscious as your brain will suffer from lack of blood supply.
What happens if something goes wrong?
Disease of the SINUS NODE is more common with increasing age and is called sick sinus syndrome. Disease of the AV NODE can be from birth (congenital) or may be acquired later and leads to HEART BLOCK (which means block of electric conduction at the AV NODE). Heart Block might also be due to block in both the right and left electric bundles.
This might happen after a heart attack where muscle and the bundles are permanently damaged in the area of supply of the blocked artery. The symptoms of these diseases are sudden blackouts and falling called SYNCOPE.
How is it diagnosed?
The diagnosis is by an ECG or a 24 hour ECG called Holter. However, as the block may be intermittent it may show up only during symptoms. To help detect these intermittent symptoms there are EVENT MONITORS that the patient activates when he has symptoms and the machine records the ECG during the symptoms. The basis of all tests of the electric system of the heart is therefore the ECG.
The treatment for diseases that impair impulse generation or impede or block conduction, is by implantation of a pacemaker. The pacemaker is a battery with a small electronic circuit that is implanted underneath the skin of the chest. An electric wire is routed from this generator to the right side of the heart through the veins. This is a minor surgery and the patients can be discharged the same day. The electronic circuit senses electric impulses of the heart and whenever there is a deficiency it gives out an electric impulse to the heart muscle to keep the heart ticking. After around 10 years the battery needs to be replaced.
About The Doctor:
Dr. V S Ramchandra is an eminent Cardiologist in Hyderabad, with more than 20 years of experience in Cardiology, practising at Sri Sri Holistic Hospitals, Kukatpally. He is also a Visiting Consultant at Apollo Hospitals, Continental Hospital and Narayan Hrudayalaya.
Dr. Ramchandra was Professor and head of cardiology at Kasturba Medical college , Manipal in 2005. He was later head at NH, Hyderabad. He has completed Board accredited fellowships in Interventional Cardiology at UAB, Alabama, USA, Pediatric EP at Chldrens Cincinnati and fellowship in Adult EP and Pacing at Indinapolis. He is Fellow of the American college of cardiology, European society of Cardiology and the Society of Cardiac Angiography &Intervention.
Despite his extensive experience in Cardiac Interventions and procedures his main interest lies in prevention of heart diseases as he believes this only can make a dent on the enormous burden of the disease in ìndia.
About the Hospital:
Sri Sri Holistic Hospital is a leading 100 bedded multi specialty hospital in Nizampet, Kukatpally, Hyderabad. Sri Sri Holistic Hospital provides high standards of healthcare with a combination of advanced technology and state of art clinical expertise. With more than 52 Internationally experienced doctors and 400+ staff, we served at least 50,000 patients so far.