A healthy heart beats 60-90 times per minute when you are at rest. When you experience conditions such as stress, anxiety, when you physically exert yourself at the gym or perform a strenuous activity, you can literally feel your heart pounding away in your chest. The normal heart beat when you are physically active is upto 100 beats a minute. However, imagine a scenario in which your heart beats much too rapidly, even when you are not exerting yourself in any way, leading to an unpleasant awareness or consciousness of your own heartbeat.
"Tachycardia basically refers to a high heart rate above 100 beats/ minute. When the heart beats above 180/min it can be very dangerous, a condition called tachyarrhythmia," says Dr. Mrinal Kanti Das, a Kolkata based cardiac specialist and a member of the Executive Committee of the CSI (Cardiological Society of India). Some patients with tachyarrhythmia have been known to register heart rates of up to 400 beats per minute. Even when your heart beats too fast, the rhythm of the beat can be regular or irregular. Irregular tachycardia usually concerns your doctor more.
Fatal flutter
Why is tachycardia considered a great health risk? When your heart beats too rapidly and often irregularly, there just isn't enough time for the upper chambers of the heart to fill up with blood. As a result, when they contract without filling up properly, blood flow to the rest of the body is severely compromised. "In such a situation, symptoms such as giddiness, palpitations, severe sweating, breathlessness can arise. There is a possibility of unconsciousness and fainting during an episode. For this reason, patients should be monitored carefully and great care should be taken to ensure that they do not panic or exert themselves, especially during an attack. Encourage the patient to take deep breaths which will to a certain extent minimize stress. If the tachycardia is associated with a heart attack and low BP, elevating the legs may help," says Dr R. Subramaniam, cardiac specialist and prof of cardiology, SRM Medical college, Chennai.
Who's at risk?
Tachyarrhythmia is most common in people above 60 (though it can affect younger people and children). It is caused by many underlying health issues in the body. In order to treat it effectively, it's important to diagnose the disease that is causing this condition.
"If your heartbeat is below 150 beats/minute and is regular even at that pace, the tachycardia could be a result of factors such as anxiety, certain fevers, thyroid problems, smoking or even hearing difficulties," says Dr MK Das. Tachycardia is often linked with high blood pressure, anemia, co-genital heart defects (that prevent proper pumping of blood to the heart) and an overactive thyroid (hyperthyroidism). A previous heart-attack can also put you at risk."
'Short-circuiting' the heart
The heart is a miraculous organ that works on a series of electrical signals and impulses. "A natural pacemaker called the sinoatrial node (SA) dictates the rate of your heartbeat," says Dr Subramanian. "This SA node communicates with key areas of the heart, making the pumping of the blood possible. Just as a sudden surge of electricity can short circuit the wiring of your home, when the electrical impulses from the heart's upper chambers for some reason are fired abnormally, it can interfere with the impulses from the SA node. In effect, this could 'short-circuit' your heart, causing very dangerous conditions called ventricular tachycardia and supraventricular tachycardia." This is usually seen in people with heart problems.
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In another similar condition called ventricular fibrillation, the electrical impulses can become so chaotic that it can cut off blood supply to all vital organs. "Today, advanced treatment for these conditions is available, though expensive," says Dr Subramanian. "The heart is shocked back into its normal rhythm with an instrument called an AED (Automated External Defibrillator). An ICD (Implantable Cardio Defibrillator) can also be implanted surgically to prevent future attacks."
If you are experiencing irregular heartbeat and are doubtful about whether it could be harmful, you can opt for a holter monitor, which is a small, portable ECG, which will track your heart rate for 24 hours as you go about your daily activities. This information will allow your physician to judge if there's cause for alarm.
Simple lifestyle changes too can minimize (if not entirely prevent) palpitations. Get plenty of rest. Stop smoking and avoid caffeine, for this can stimulate the nervous system. Experts caution against drinking more than two cups a day. According to the NIH (National Institute of Health) in the US, certain diet pills and drugs may lead to a rise in heart rate. If you're experiencing palpitations, it's best to discuss your medication with your doctor.
