Dr Darren Green explains how to avoid the dangers of a low heart rate. QUESTION: I am a pensioner in extremely good health. However, recently I had a bad fall at home and bumped my head, resulting in an ambulance dash to hospital. After some tests, the doctors told me that my results suggested my heart was beating too slowly. I would welcome your comments.
ANSWER: Physicians are often focused on the injury rather than cause of the triggering factor. What caused the fall and did you lose awareness or have what people commonly term a blackout? You were very fortunate that you did not fracture your skull or any limbs. The diagnosis soon became apparent: it looks from the information you have supplied that you collapsed because your heart suddenly slowed. The subsequent 24-hour monitoring of your heart rate in hospital revealed at least one period of very slow heart rate – you tell me at one stage it was 31 beats per minute, when a normal rate is around 60 to 80 beats.
Syncope is the medical term used to describe collapsing or fainting suddenly. Heart rate can vary slightly with mood, temperature, whether you have been eating, and other factors – for instance drugs such as betablockers, used for high blood pressure, can lower heart rate. However, a pulse of less than 50 is considered slow and in your case seems to be the first evidence of a problem with the heart’s natural pacemaker, the sino-atrial node. This is a condition known as sinus bradycardia, or sick sinus syndrome, and affects people of all ages, though it becomes more common as we age. If left untreated, it could be unsafe, as an episode of slow heart rate could result in not enough blood reaching your brain, triggering a faint or collapse – as you have experienced.
I recommend that you be referred back to hospital for the attention of a cardiologist. Consideration will immediately be given to fitting you with a pacemaker, if this bradycardia is significant. This is a device that is not much bigger than a large thick coin. It is placed, during a minor operation under local anaesthetic, under the skin of your upper chest, and a fine, flexible lead connects it to the inside of the heart; once it is in place, you will not be aware of it.
The technology monitors your heart rhythm, and if this falls below a certain rate, it switches on, and with a tiny electric current stimulates the heartbeats at a healthy and correct rate. Periodically, doctors can scan the device to ascertain the recent history – how many times it has had to deliver an electrical shock, for instance. The battery will last for several years before the device has to be changed.
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