The heart is a strong, hollow muscle about the size of a fist. It lies in the centre of the chest and is tilted slightly to the left. The heart beats continuously throughout life, usually between 60 to 90 times per minute. It is divided into two sides – left and right – and has four chambers. The two upper chambers are called the atria and the two lower chambers are known as the ventricles.
Its job is to pump blood, oxygen and nutrients to all parts of the body.
When we breathe in we take in oxygen, which is vital to keep all living tissues healthy and working well. The oxygen enters our blood stream and the left side of the heart pumps the blood around our body via the arteries, delivering oxygen to the tissues, muscles and organs.
As the tissues use the oxygen, they make carbon dioxide, which is removed in the bloodstream. This is taken to the right side of the heart to be pumped to the lungs where we breathe out the carbon dioxide and breathe in vital oxygen. This is a continuous process.
The pumping mechanism of the heart is controlled by electrical signals, produced in the heart itself.
Below is a diagram of the complex electrical signals pathway in the heart. The purple lines indicate the way that the signals pass within the heart, stimulating the heart muscle to contract and pump the blood around the heart and out to the body.
If, for some reason, this pathway becomes damaged or ceases to function properly because of a disruption to the electrical signals, or if the heart muscle has been damaged by disease as the result of, for example, a previous heart attack, high blood pressure, or disease of the heart valves, then the heart will not pump as well as it should during each heartbeat. This can lead to heart failure.
What is heart failure?
You will have seen a consultant cardiologist and been told that you are suffering from heart failure. This term covers a range of heart conditions resulting in the heart muscle’s inability to pump blood efficiently around the body.
If the heart is no longer able to pump enough blood, and therefore oxygen, around the body, you will have begun to suffer to a varying degree from breathlessness, tiredness and diminished exercise capacity and swelling in the feet and ankles due to fluid retention. This can make you feel very unwell. You may also develop serious heart rhythm problems (arrhythmias) which could be a threat to life.
Heart failure, however, does not mean that your heart is going to stop beating at any minute, but it does mean that you need treatment to relieve your symptoms and regulate your heart beat way, thus allowing enough blood to be pumped around the body.
What are arrhythmias?
Arrhythmias are disturbances of heart rhythm. The electrical activity of the heart becomes abnormal, this can result in symptoms such as palpitation, breathlessness, chest pain, dizziness and blackouts.
Some of the arrhythmias are benign, while some can be more serious. Certain arrhythmias such as Atrial Fibrillation (AF) are associated with increased risk of stroke and heart failure. Hence, early detection and treatment is vital.
How does a pacemaker work?
A pacemaker consists of a battery, a computerised generator, and wires with sensors called electrodes on one end. The battery powers the generator, and the wires connect the generator to the heart.
A pacemaker monitors your heartbeat and helps to control it. It does this by detecting your heart's electrical activity and sending information through the wires to the computer in the generator. If your heart rhythm is abnormal, the computer will direct the generator to send electrical pulses through the wires to your heart.
Modern pacemakers can also monitor your movement, blood temperature, breathing, or other factors and can adjust your heart rate to changes in your activity.
The pacemaker's computer also records your heart's electrical activity and heart rhythm, which will help your consultant to adjust your pacemaker so it works better for you. This can be done via an external device, so there is no need for your consultant to use needles or have direct contact with the pacemaker.
What is an Implantable Cardioverter Defibrillator (ICD)?
An ICD is an Implantable Cardioverter Defibrillator, which is a metal device, consisting of a box the size and weight of a small pack of playing cards containing a battery powered computerised electronic device. It has one or, sometimes, two leads (or wires) which are connected to the heart, usually via the veins.
It is usually implanted under the skin of the left chest wall in a ‘pocket’ behind the muscle, where it will receive signals from the leads and continuously monitor your heartbeat.
It is programmed to respond to your individual heart rhythm, based on the information we obtained during your tests and investigations.
The ICD will detect any abnormal heart rhythms as soon as they occur and treat them by delivering a series of electrical impulses known as pacing. It will also deliver a small electric shock, to restore your normal heartbeat, when pacing alone is not sufficient.
Both these treatments enable the heart to return to its normal rhythm, working much more effectively than drugs alone. However, continuing to take your heart drugs may reduce the frequency of the arrhythmias. Your cardiologist will decide if this is the best treatment for you.
When the ICD pacing impulses are restoring your heart rhythm you may have already begun to feel slightly unwell, but should experience at most a slight fluttery feeling as the impulses restore your heartbeat to normal.
Infection in the wound or the lead(s) themselves within the blood vessels, but you will be given antibiotics before and after the procedure, to reduce these risks.
Failure of the device to function properly.
As previously stated, risks are rare, but it is our duty to make you aware of them, before you sign the consent form to allow us to go ahead with the treatment. Please do not hesitate to ask your doctor any questions you may have to help allay any concerns, prior to signing the consent form.
Remember that having an ICD fitted will reduce the risk from any future heart rhythm problems and may allow you to get on with your life with fewer restrictions.
What is Cardiac Resynchronisation Therapy (CRT)?
CRT (cardiac resynchronisation therapy) is also known as biventricular pacing, because each ventricle will have a lead (or wire) placed in it, via a blood vessel, capable of producing an electrical impulse to stimulate the heart muscle. Electrical impulses from these leads will have a positive effect on controlling your heart rhythm, by ensuring that your heart beats in a coordinated way, allowing it to pump more efficiently. This should improve some of the symptoms you experience as a result of your heart failure.
CRT not only ensures that your heart rhythm is monitored and stabilised, but also that an electric shock can be delivered to the heart muscle via the defibrillator in the event of a life threatening arrhythmia.
In general, patients who are more likely to benefit from this device are those with:
Moderate to severe heart failure symptoms, despite drug therapy
A weakened and enlarged heart
An electrical pathway problem, causing uncoordinated pumping of the ventricles
Since not all people benefit from this therapy, your consultant will have had to undertake a full assessment of your condition before the decision was made to fit a CRT pacemaker/defibrillator (CRT-D).
What is Atrial Fibrillation (AF) Ablation?
AF is one of the most common abnormal heart rhythms; people with AF have an irregular and sometimes fast pulse. Normally, your heart’s natural pacemaker sends out regular electrical impulses. AF happens when those impulses fire off from different places in the atria (the top chambers of the heart) in a disorganised way.
Pulmonary Vein Isolation Ablation (PVAI) can effectively cure AF and Coventry & Warwickshire Heart Rhythm can offer a number of state-of-the-art technologies to address the problem in different types of patient.
AF Ablation as an alternative to medical treatments
The initial treatment for atrial rhythm abnormalities is antiarrhythmic drugs. These drugs can slow the conduction of the AF or can restore sinus rhythm. However, drugs cannot cure a heart rhythm disturbance. Many patients are unable to tolerate these drugs. Patients on these drugs require strict follow up care and checks, because antiarrhythmic drugs can sometimes cause abnormal heart rhythms.
Patients with AF are more at risk of stroke, heart failure and dementia, and so may be on warfarin. This means that careful monitoring of the blood is also required. In some patients successfully cured by catheter ablation for AF, long-term anticoagulation with warfarin may be avoided.
What is Catheter Ablation for AF?
In the last 10 years, more and more breakthroughs have been achieved in the understanding of AF, and how it can be treated. The most important breakthrough came in the understanding that the pulmonary veins are a very important source of extra beats that trigger AF. In addition, it has become clear that ablation around the mouth of these veins can prevent the extra beats, and prevent the triggering of AF.
Over time, the catheter technologies for achieving this have developed. At the simplest level, a circular ablating catheter can be delivered through a keyhole in the groin, passed across to the left side of the heart, and placed around the veins for ablation. This is safe, effective and rapid. In more difficult cases a further range of catheters may be needed. The approach is guided by x-rays, but also by a state-of-the-art “mapping” system, which is like a mini-“sat-nav” guiding the movement of the catheters.
Who can benefit from AF Ablation?
Symptoms of this disease can be quite different from individual to individual. Some may have no symptoms and their condition will go unnoticed until a physician detects it during routine examinations, others may have slight symptoms or are very sensitive to the slightest sensations.
The most common symptoms are shortness of breath, light-headedness, palpitations and / or chest discomfort. However, patients with AF have one thing in common. This is that AF tends to get steadily worse over time, with more AF, lasting longer, and finally becoming continuous. This is when we know that there is the greatest risk of stroke.
What happens during AF Ablation?
Dr Osman and Dr Ng are using a new technology called Ablation Frontiers. This involves placing two catheters in the right side of the heart at the start and performing a trans-septal puncture. Once into the left heart they take pictures of the veins and use this new and novel technology to map and ablate around the pulmonary veins with a single catheter (PVAC catheter). They can also ‘draw’ ablation lines in the heart with another catheter (called TVAC) at the same sitting. This technology is as effective as 3D mapping, takes less time than 3D mapping and is therefore often better tolerated by patients.
The content contained within this website is not produced by BMI Healthcare Limited (BMI) and BMI shall have no liability for errors, omissions or inadequacies. BMI also does not guarantee the website timeliness, completeness or performance.