Source: er.knowledge.ca
We electrophysiologist like to create an illusory perception that we are akin to wiremen when it comes to troubleshooting heart rhythm problems. Usually when we first share our diagnosis to patients that they are suffering from complete heart block, the common question that I would get is, “Doctor, is my blood vessel in my heart blocked?” and my quick response would be, “NO, of course not”.
I would like to take this opportunity and the platform to share what exactly is “heart block” with the public and what it means to suffer from a complete heart block.
We know that the heart has 4 chambers, upper two, known as atrium and the lower chambers called ventricles. The heart pumps minimum of 86400 times a day, bearing in mind, it doesn’t stop from birth till we die. So, what makes the heart beat or the heart pump so efficiently and regularly is actually the electrical signals that are produced automatically from a small area within the atrium called the SINUS NODE (SA NODE).
The signals arising from this sinus node travels down the ventricles via the ATRIOVENTRICULAR NODE (AV NODE) and along the way causes the atriums to contract. Interestingly, this AV node has a very special task that is to guard the speed of the electricity conducted from atrium to ventricles. Commonly also known as the gatekeeper. From the AV node, the signals travel down specialized cells which, almost like our housing electrical wiring system, making sure the signal from the SA node reaches the heart muscles and cause the ventricle to contract and pump the blood out to the body.
Great, now that you have understood basic wiring system in the heart, heart block basically means, the electrical signals that controls the heartbeat is partially or completely blocked from reaching ventricles from the atrium thus slowing the heart rate.
Who suffers from this problem?
It can be present at birth (congenital) or you develop this problem later in life (acquired) due to reasons such as heart attack, inflammation to the heart muscles, medication, ageing and other various reasons.
What are the symptoms that I may suffer if I have a heart block?
Most of the time, these patients are asymptomatic (without symptoms) and the condition is picked up when ECG is done. Symptoms usually depend on severity. The third degree is usually more symptomatic than first degree. Symptoms include dizzy spells, blackouts, fainting episodes, shortness of breath and occasional chest pain.
How many type of heart blocks are there?
There are 3 types: first, second and third degree heart block (also known as complete heart block). First being the mildest and third being the severe form of it.
How does one get diagnosed with heart block?
This is entirely an ECG diagnosis. ECG is a tool used by doctors since many years ago to record the heart’s electrical activity to diagnose various problems with the heart. Occasionally, HOLTER, a form of ECG recording, is used to record the heart electrical activity for 24 hours continuously. The degree of heart block is determined by the pattern of the ECG.
Is treatment required and is there any form of treatment for this condition?
Treatment depends of the cause and the degree of the heart block. For first and second degree, there is no treatment required unless you are symptomatic. Patients with third degree will definitely require treatment. The treatment depends on the underlying disease. Reversible causes such as medication induced or heart attack may resolve spontaneously once the underlying problem is treated. If it remains permanently in third degree heart block then these patients need pacemakers.
What is a PACEMAKER?
A pacemaker is a match box size device, with the thickness of a older version of 50 cent coin that is implanted just beneath your skin near your left collar bone (sometimes right collar bone). There is a wire, which is inserted from the pacemaker through the vein to the right side of the heart. This procedure is done in electrophysiology lab and under heavy sedation for the patients. After the procedure there will only be a small scar visible but not the pacemaker. This device uses electrical pulses to prompt the heart to beat at a normal rate.
What happens if I have third degree heart block and I refuse to have a pacemaker?
There is a risk of complete heart block if left untreated, which may lead to sudden cardiac arrest and death.
If I have a pacemaker, will my lifestyle be restricted?
Usually, the first 6 weeks is essential where the patient follows the doctor’s instructions to ensure that the wires are stabilized in their position. After this, apart from contact sports, patients can normally resume back to their normal activities.
Will I need to be followed up by cardiologist?
Yes. These patients need to be followed up periodically to ensure the pacemaker is functioning normally and optimally. Usually pacemaker lasts around 10 years after which it needs to be replaced.
Dr. Barveen Aisha Abu Baker (MBBS IIUM, MRCP UK) is a fellow in the Electrophysiology unit in IJN, Kuala Lumpur.
[This article belongs to The Malaysian Medical Gazette. Any republication (online or offline) without written permission from The Malaysian Medical Gazette is prohibited.]