Inside the human chest, a tireless engine performs a rhythmic masterpiece roughly one hundred thousand times a day. If you imagine your heart as a finely tuned orchestra, every beat follows the precise baton of a rhythmic conductor, ensuring that life-sustaining blood flows in a perfect, measured cadence. This conductor is the sinoatrial node, a tiny spark of biological electricity that initiates signals travelling from the atria, upper chambers of the heart, to the ventricles, the lower chambers. Over a lifetime, this system produces nearly 300 crore beats — perceived externally as the pulse — while the atrioventricular (AV) node acts like a sieve, regulating the surge of impulses to ensure the heart pumps with maximum efficiency.
The AV node is located in the wall between the atria, near the bottom of the right atrium. The AV node slows the signal just a little, like a traffic light, so that the atria have time to squeeze blood into the ventricles before they pump.
However, for millions of people, this internal symphony is suddenly interrupted by a jarring dissonance known as atrial fibrillation (or AFib). When AFib takes hold, the conductor effectively drops the baton, and the heart’s electrical strings begin to quiver chaotically. Instead of a single, powerful signal, multiple erratic impulses fire simultaneously. As Dr KK Narayanan Namboodiri, professor of cardiology at the Sree Chitra Tirunal Institute for Medical Sciences and Technology (SCTIMST), explains, against a normal rate of 60-70 beats per minute, AFib can send the atrial rate soaring above 300. At this speed, the heart does not have time to absorb blood, and without adequate filling, it cannot pump effectively.
This disorganised “quiver” creates a secondary, more sinister danger. Because blood is no longer being moved efficiently, it can pool in a small pouch of the heart, where it thickens into clots. If a clot breaks free and hitches a ride to the brain, it triggers an embolic stroke — a reality that makes those living with AFib five times more likely to suffer a stroke than the general population. Dr Namboodiri warns that the first episode itself can sometimes present as a stroke, and even when a major stroke is avoided, micro-clots can lead to ‘subclinical’ issues like memory impairment and brain atrophy.
Traditionally, AFib was viewed as a disease of the elderly, a natural result of the ‘wear and tear’ of aging. Statistics do support this: the risk rises significantly after age 60, with a prevalence of about 5-8% among those over 80. Dr Mathew Iype, head of Cardiology at Government Medical College, Thiruvananthapuram, notes that age-related degeneration and the resulting dilation of the atria are primary drivers.
“Because this system usually runs so quietly, many people don’t realise when their heart rhythm becomes irregular. In fact, many people only discover they have it by surprise during a doctor’s visit for a completely different health issue,” he said. Yet, the trends in the Indian subcontinent are shifting dramatically. AFib is no longer just a disease of the old.
Consider the case of Venugopal, a 45-year-old school teacher from Kochi. A routine checkup uncovered AFib, leaving him and his family stunned. His case is far from an isolated incident. “It is not that surprising considering the fact that 20% of my AFib patients are below the age of 55,” says Dr Namboodiri.
While the average age of AFib patients in Western countries is around 65, in India, it is frequently diagnosed between ages 45 and 55. This younger onset is increasingly linked to modern lifestyle factors: obesity, undetected hypertension, diabetes, sleep apnea, and excessive alcohol use.
For many, this internal storm is invisible, carrying no symptoms at all — a condition known as subclinical AFib. Others might feel an unsettling flutter, a fast, pounding heartbeat often described as a “flopping fish” in the chest, accompanied by shortness of breath or unexplained fatigue. These episodes may be paroxysmal, coming and going like a passing storm; persistent, lasting up to a year; or permanent.
Regardless of the frequency, the condition is a burgeoning public health crisis. Data from the Indian Heart Rhythm Society (IHRS) AFib Registry reveals that the condition rarely travels alone. In the Kerala-AF Registry, hypertension was present in over 61% of patients, while coronary artery disease affected nearly 40%.
The stakes are high. With a sobering annual mortality rate of approximately 16.5 per 100 person-years among non-valvular AFib patients, the medical community now classifies AFib as the next epidemic among non-communicable diseases.
As research continues to refine our understanding of this silent storm, the message to the public remains clear and deeply personal: your heart’s rhythm is its language. If it skips a beat or enters a frantic, irregular dance, it isn’t just a quirk of fatigue; it is a vital call for survival. We must learn to listen.