When your heart’s rhythm is faster than the recommended 60 to 100 beats per minute, it’s time to listen to it. The Conversation Africa’s Health and Medicine Editor Joy Wanja Muraya spoke to Dr Harun Argwings Otieno on why your heart is sending those chaotic electric signals and how this can be managed.
What causes an irregular and often rapid heart rate? Why is it so dangerous?
When your heart has an irregular or abnormally slow or fast rhythm, it fails to pump blood around your body as efficiently as it should.
This condition known as atrial fibrillation is characterised by a rapid, irregular pulse and has a significant association with an underlying heart disease.
Though the exact cause isn’t clearly understood there’s evidence that the abnormal electrical signals arising from the left atrium lead to the chaotic, disorganised beats that are characteristic of atrial fibrillation. There’s a strong association with high blood pressure, ageing, diabetes mellitus, valvular heart disease and coronary artery disease.
In coronary heart disease, your arteries are narrowed or blocked by a build-up of cholesterol. Lack of treatment can lead to heart attacks.
In valvular heart disease, a defect or damage to one of the four heart valves allows blood to leak abnormally.
The valves may either be too narrow to open fully, or they are unable to close completely thus blood flow in and out of the heart is uncoordinated. Valvular heart disease may require surgical treatment to correct the defect.
Atrial fibrillation frequently develops in patients with severe rheumatic heart valve disease involving the mitral valve.
Rheumatic heart disease which is caused by an untreated streptococcal throat infection is another culprit that affects the heart this way.
Some lifestyle conditions like excessive alcohol intake and abnormalities of the thyroid function can also lead to atrial fibrillation.
How does the heart work and how does this disease affect its functionality?
The normal heart rate lies between 60 and 100 beats per minute.
This function originates from the top side of the heart known as the atrial pacemaker that sends signals to the bottom of the heart, ventricles, in a coordinated fashion, known as normal sinus rhythm.
When the heart is affected, some of the prominent symptoms of the disease includes an irregular heartbeat, easy fatigability, fainting or dizziness.
The real danger with atrial fibrillation is that it may lead to a stroke.
What’s the situation of atrial fibrillation in Kenya?
Kenyan data on this heart condition is scarce. But between 2008 and 2010, we conducted a study at the Aga Khan University Hospital Nairobi.
We recruited 162 patients with confirmed atrial fibrillation from 22,144 general hospital medical admissions over a three year period. The average age of patients was 67 years. We analysed them for risk factors and treatment.
Close to 70% of them had high blood pressure, 38% had heart failure, 33% had diabetes mellitus and 19% coronary artery disease. A third of the patients experienced palpitations, dizziness or fainting but 15% had a serious complication of a stroke or an abnormal blood clot.
About 6% died within six months and about 12% were readmitted to hospital.
What needs to be done in the long term to prevent it?
The best management measures are prevention and maintaining a healthy lifestyle which includes balanced meals, regular exercise, proper stress management and quitting smoking and alcohol.
Controlling blood pressure, cholesterol and preventing diabetes are other tips to keep fit.
When the heart condition occurs, seeking a medical consultation to establish the underlying cause is paramount. It’s important to get an ECG (electrocardiograph) to diagnose atrial fibrillation. When ever you experience palpitations, make sure you have your heart checked.
A medical consultation with a cardiologist will advise on how to control the heart rate to prevent worsening of symptoms.
Prescription of strong blood thinners to prevent a stroke is another option to prevent this devastating complication.
In some cases, when detected early, cardiologists can use a controlled electrical shock to the heart to restore the normal heart rhythm. Medication is also used sometimes for this purpose.
How does new research promise to solve atrial fibrillation?
New medications called direct or novel oral anticoagulants are used to prevent stroke.
They work better than the older medication because one doesn’t need to have regular blood tests to check for the effectiveness of the blood thinner.
Warfarin, a prescription medication used to prevent harmful blood clots from forming or growing, is commonly used.
But its use must be monitored frequently as the medication warns to stay away from certain foods or medications which could interfere with the effectiveness of the blood thinners.
New approaches to treatment include atrial fibrillation ablation, where an electrical current or cold therapy is delivered directly to the heart through specialised plastic tubes or catheters and restores the normal heart rhythm.
This technology is only just maturing and is performed by highly trained heart specialist doctors called electrophysiologists. These doctors manage the heart’s electrical system or heart rhythm disorders.
Genetic studies may reveal underlying factors associated with this condition.
In all, the most important factor in atrial fibrillation is stroke prevention, through careful risk assessment, safe and effective use of blood thinners , controlling the heart rate and restoration of normal rhythm when possible.