ATRIAL Fibrillation (Afib) is an irregular heartbeat that occurs when the two upper chambers of the heart or the atria, beat out of sync with the lower chambers or the ventricles. The loss of synchronous beating between the upper and lower cardiac chambers result in poor blood flow, which in turn can lead to the formation of blood clots within the heart cavities. Instead of the blood being pushed forward by the heart pumping, it’s just swirling around in the heart and can clot easily. The two most common complications from Afib are stroke and heart failure.

Risk factors

Ageing and hypertension are the biggest risk factor for developing Afib. Ageing has been associated with age-related changes in the electrical system of the heart. We have also shown in our own investigations published in the journal Clinical Cardiology in 2001, that hypertension can alter the electrical conduction in the heart, predisposing individuals to Afib. In our study of 318 subjects, we were able to demonstrate that electrical conduction in the upper chambers is altered and mirrors severity of hypertension, especially in blacks. Other underlying drivers of Afib include coronary artery disease, obesity, sleep apnea, and alcohol.

The American Heart Association (AHA) estimates that three out of four people who have had a stroke have high blood pressure, and one out of five stroke victims have Afib. Afib raises a person’s risk for stroke by five times, according to the National Stroke Association. Because hypertension can lead to Afib, it becomes a double burden where you have high blood pressure as well as atrial fibrillation, increasing your stroke risk. Recently published investigations suggest another potential Afib-related complication – mental decline. This is believed to be related to recurrent small blood clots in the brain, leading to cognitive decline.

Atrial fibrillation is the most common heart rhythm disorder and affects an estimated 2.7 million people in the USA. That number is expected to reach 12 million by 2050, according to the American Heart Association. The number of people admitted to the hospital for Afib increased by 46 per cent between 1998 and 2010, according to new research presented recently at the American Heart Association’s Scientific Sessions. The number of cases of Afib, already at epidemic proportions, is expected to continue to increase as the population ages and more patients with heart disease live longer.

Signs

Most people with Afib can tell something is wrong. They typically feel palpitations or shortness of breath and the heart rate will rapidly increase. On the other hand, many patients feel nothing and are totally asymptomatic until a doctor examines them, sometimes for a different condition or they obtain a routine electrocardiogram (ECG) and are discovered to be in Afib. Afib occurs in people with an abnormal heart and in individuals with structurally normal hearts. While older individuals are more at risk, young persons can suffer from Afib as well.

After performing a routine ECG at the Heart Institute of the Caribbean, Dwight*, 35, was found to be in Afib. This followed three nights of binge drinking with friends. He recalls a prior finding of Afib on ECG after complaining of chest pain. His first Afib episode felt like being punched in the chest. He was told at the time that he had “holiday heart” syndrome, a temporary cardiac rhythm disorder triggered by binge drinking or stress.

The number of people affected by Afib in Jamaica is unknown. However, given the high prevalence of hypertension in Jamaica, the number of people afflicted with Afib is expectedly significant. While most people with Afib live full and active lives, the condition is serious and can lead to life-threatening complications. It can lead to stroke, hospitalisation, as well as lost productivity. Unfortunately, the risk of stroke remains high in the absence of treatment with blood thinners, even in the absence of symptoms.

“Atrial fibrillation can occur and not cause symptoms,” said Dr Felix Nunura, consultant adult and paediatric cardiologist at HIC. “In some cases, the very frequent signals arising from the upper cardiac chambers are slowed by another area of the heart and when this happens, the overall heart rate may not change and patients may not notice any difference whatsoever.” Some individuals, for whatever reason, are also unaware that their heart is beating fast and out of rhythm.

Donovan*, a patient of Dr Nunura is one of those people. “He tolerated very rapid heart rates with his Afib and did not feel bad or notice any difference until I examined him,” said Dr Nunura.

Donovan was 73 when his Afib was discovered.

In some patients, atrial fibrillation is persistent; but Bent’s would come and go, which is why his regular physicals never caught it. Even if Afib does not cause symptoms, it is still potentially causing damage. In atrial fibrillation, the normal heart rhythm is interrupted. “Instead of clear, organised signals, there is a disorganised electrical storm in the upper heart chambers and the heart quivers, and the filling of the lower chambers from the upper chambers becomes ineffective,” said Dr Joel Brooks, interventional cardiologist at HIC. “The pumping function of the heart can also decline and patients can go into heart failure.”

Treatment

When it comes to treatment, the first priority is “a stroke prevention strategy” which, depending on the patient’s other risk factors, may just be aspirin or more potent blood thinners. Second is making sure the heart rate is controlled. If it’s very rapid for weeks, it can damage heart muscle, resulting in cardiomyopathy and heart failure. Controlling sleep apnea, high blood pressure and obesity could be quite helpful in managing Afib.

A more potent treatment is radiofrequency ablation, a procedure that prevents irregular electrical impulses being sent from the heart’s upper chambers to the lower. In this procedure, a burst of electricity, or sometimes extreme cold, is used to destroy the small region of cells where the chaotic electrical signals are originating. Ablations are typically successful in younger patients who have otherwise healthy hearts.

Professor Ernest Madu, founder of the Heart Institute of the Caribbean, is an internationally acclaimed cardiologist and expert on innovative health solutions. HIC is a centre of excellence for cardiovascular care in the English-speaking Caribbean. Please send questions and comments to emadu@caribbeanheart.com or call 906-2105-8.