Everything you should know about a heart pacemaker
When we talk of heart disease, the image that comes to mind is often that of a heart attack, which involves a disfunction of the blood vessels. However, the electrical system of the heart is also often at fault. If a heart attack occurs due to a problem with the heart’s plumbing of the heart, then a heart block occurs due to a problem with its wiring. The interesting thing about this is that our hearts are really a big of muscle, but some cells are specialised to work as electrical conductors or natural pacemakers.
The heart’s natural timer, ie, the sinus node, which sits at the top right side of the heart, produces regular timed electrical pulses, which are then conducted by specialised muscle fibres to a second choke point, the AV node, which is located at the junction of the upper and lower chambers. The current then fans out to the lower pumping chambers from here, leading to regular pumping of the heart, as reflected in the ECG.
Dr Rajiv Agarwal, Principal Director and Unit Head, Cardiology, Max Smart Super Speciality Hospital, Saket, New Delhi, says, “If your heart beats slower than 60 beats per minute, you could be suffering from a serious medical condition called bradyarrhythmia. As a result of a slower heartbeat, blood flow to the brain and other organs can be reduced, leading to sudden cardiac death due to slowing or stopping of the heart and even falls, especially in older people, due to fainting.”
The symptoms include fatigue, chest pain and shortness of breath after any physical activity like walking up the staircase. It may cause blurred vision and a confused state.
A pacemaker is a small, batteryoperated, computer-driven device that’s typically implanted just beneath your skin, usually in the chest area right under the collarbone. “Small wires connect the pacemaker to your heart. When the pacemaker’s computer senses an abnormal rhythm, it sends electrical signals through the attached electrodes to your heart, jump starting it back into an appropriately timed beat,” explains Dr Agarwal. By delivering electrical impulses to the heart muscle, pacemakers synchronise its contractions, thereby maintaining optimal blood flow and oxygen delivery throughout.
Pacemakers are inserted in the cath lab via a small incision by the cardiacologist. “After its installation, the heart starts to work better, allowing patients to enjoy physical activities with fewer side effects. A pacemaker can also be programmed to act during episodes of bradycardia,” Dr Agarwal adds.
There are many advances over the basic pacemaker. Doctors may install a pacemaker with three wires for weak hearts to make the heart contract in a more efficient manner. This device is called a biventricular pacemaker.
Pacemakers can also work when the heart produces an abnormal and fast current, leading to a rhythm disturbance called ventricular fibrillation or tachycardia. In such cases, the specialised device can deliver an internal shock, which resets the heart rhythm to normal. This device called the implantable cardioverter defibrillator, or ICD, has saved many lives. According to Dr Agarwal:“Many patients need and receive a combined CRT-D for a weak heart that is prone to ventricular fibrillation. Patients with blocked veins may receive a leadless pacemaker, which is a small capsulesized device placed directly inside the right ventricle, non-surgically.”
Pacemakers are more than just a medical intervention. They help stabilise heart rhythms and mitigate symptoms such as fatigue and dizziness and enable patients to engage in daily activities and pursue their hobbies.