The Heart The heart, although one of the most important organs in the body, is simply a muscular pump. It pumps blood containing oxygen and other essential nutrients around the body, and delivers waste products to the kidneys and lungs. For the heart to pump effectively it requires its own blood supply, which it receives from the three coronary arteries, and a regular and reliable heart beat, which it derives from its own electrical conduction system.
A problem with the coronary arteries or the electrical regulation of the heart can translate into physical symptoms such as:
Coronary artery disease is caused by atheroma, an accumulation in the arteries of fatty deposits made up primarily of lipids and calcium. As the diagram opposite demonstrates, over time the build-up of these deposits makes it more difficult for blood to pass through the vessels, and may even cause a complete blockage which may in turn lead to a heart attack.
Symptoms - Chest Pain
Coronary artery disease is caused by atheroma, an accumulation in the arteries of fatty deposits made up primarily of lipids and calcium. As the diagram opposite demonstrates, over time the build-up of these deposits makes it more difficult for blood to pass through the vessels, and may even cause a complete blockage which may in turn lead to a heart attack.
With exercise or emotional stress, more blood is needed through the coronary arteries to supply the heart muscle with the blood and oxygen it requires to beat faster. Over the years the coronary arteries may become narrowed and furred up, initially causing no symptoms whatsoever. As the furring up process continues there comes a time when the heart cannot get enough blood through the coronary arteries to cope with stress or increased activity, when walking uphill or climbing stairs, for example. This reduction in blood supply can cause chest pain, pressure, heaviness or tightness (angina) which rapidly disappears with rest or certain medication (a GTN spray or tablets).
If the furring up in an artery is so great that a blockage occurs, the patient experiences a heart attack, or myocardial infarction. The pain is particularly intense and is not relieved adequately by rest or GTN. This is a medical emergency and the patient should be admitted to hospital immediately to unblock the artery and treat the consequences of the heart attack.
Breathlessness, or dyspnoea, is a common symptom of several medical disorders. Increasing age and lack of physical activity can cause some degree of breathlessness, but difficult or painful breathing should always be fully investigated by a doctor to look for an underlying heart or lung disorder. If the heart muscle is not pumping effectively, pressure can build up within the lungs and the chambers of the heart, creating the sensation of breathlessness. If the muscle impairment is mild, breathlessness is only felt with significant exercise, but increasing muscle damage causes breathlessness with even mild activity and is perhaps more noticeable when lying down in bed, such that a patient may start to sleep with more pillows than before.
The most common cause of breathlessness is ischaemic heart disease or atherosclerosis, the furring up of the coronary arteries. If an artery blocks completely and causes a heart attack, the heart muscle that was supplied by that artery will die, healing with time to leave a scar. The larger the scar, the greater the effect on the remaining healthy heart muscle, and the more likely it is that a patient may feel breathless. Other causes of breathlessness include malfunctioning heart valves that may narrow down and/or leak, and various abnormalities of the heart muscle itself, which may be inherited, or acquired (e.g. following a viral infection of the heart or a long period of alcohol excess).
Symptoms - Palpitations, Dizzy Spells and Blackouts
Palpitations are a common symptom that may or may not signify an important underlying heart problem. An awareness of occasional heart beats is common and normal. We all experience extra heart beats from time to time and in most cases this is not dangerous, although it may initially be concerning to the patient. Sometimes the heart rhythm can change significantly and this needs careful investigation, for example with an ECG or 24 hour heart monitor.
There are many different types of heart rhythm change, which, depending on the precise rhythm abnormality, can be treated in several different ways, for example with regular medication, a permanent pacemaker, or an implantable defibrillator.
Some heart rhythms can be successfully treated, often permanently, with the brief application of radiofrequency energy through small catheters (tubes) passed through the veins into the heart chambers. This is a technique called radiofrequency ablation.
Dizzy spells and blackouts may be caused by a drop in blood pressure, which temporarily reduces the supply of oxygen to the brain. This may occur when getting up quickly from a lying or sitting position (postural hypotension), and can be exacerbated by certain medications, such as those to control high blood pressure. Many dizzy spells and faints do not have a significant underlying cause but they should always be investigated, particularly if they are accompanied by other symptoms, as they can sometimes be indicative of a cardiovascular disorder such as a heart rhythm disturbance or a heart valve problem.
For more information on the following forms of investigation and treatment, please click on a title to be taken to a pdf information booklet for you to download and print:
• ECG (electrocardiogram)
• Echocardiogram
• 24 hour ECG
• Exercise Tolerance Test
• Chest X-ray
• Angiography
• Angioplasty
This information booklet will talk you through the routine investigations that you may be required to have to form a diagnosis or monitor your condition. These include:
• ECGs
• Echocardiograms
• 24 hour monitors
• Exercise tolerance tests
• X-rays
An ECG is a tracing of the electrical activity of the heart, which can be instrumental in identifying an abnormal heart rhythm or showing evidence of a prior heart attack. The test takes only a few minutes and involves sticking several small patches to the arms, legs and chest, which are connected to electrodes that record the electrical impulses generated by each heartbeat.
A 24 hour tape is essentially an ECG that takes place over 24 hours. Tracing the electrical activity of the heart over a longer period of time than a standard ECG can help to diagnose symptoms such as palpitations, which do not occur all the time. As with a standard ECG, small patches are stuck to the chest, which are attached to wires leading to a portable recorder worn on a belt around the waist. Once the system has been set up you can go about all your daily activities as usual, but should avoid swimming, bathing and showering until the 24 hour period has come to an end. You will also be asked to keep a diary of any symptoms you experience during the time you are wearing the monitor, so that the doctor can pay special attention to the recordings made at those times and determine whether the symptoms are related to the heart.
The standard echo (tranthoracic echocardiogram) uses ultrasound to look at the structure and function of the heart. It takes about twenty minutes and is performed on an outpatient basis. It is painless and safe. A small handheld ultrasound probe is moved over the front of the chest wall to produce images of the beating heart on an adjacent monitor. The size and shape of the various heart chambers can be seen, together with the movement of the heart valves. A vast amount of information can be produced, which helps greatly with the diagnosis and management of a wide variety of heart conditions. For example, the effects of a heart attack on the heart muscle can be accurately assessed and many different causes of breathlessness can be identified.
An exercise tolerance test is an ECG carried out while the patient exercises on a treadmill. Chest pain or other symptoms during exercise can be indicative of angina, a specific type of pain caused by coronary heart disease. An exercise ECG can therefore help to diagnose coronary heart disease, and in patients known to have this condition it can give more detailed information about the severity of the illness and help doctors to establish a treatment regimen. The test usually takes about half an hour, beginning at a very easy rate and gradually made harder by increasing the slope of the treadmill. Your ECG reading will be monitored constantly by a doctor and a technician, and readings will continue to be taken in the recovery period after exercising. The test can be stopped at any time if you develop any chest pain, breathlessness or fatigue. You should make sure that you are wearing comfortable clothing and shoes suitable for exercise. There are facilities available to shower afterwards, if you so wish. Figure 2: An echocardiogram² showing a leak through the mitral valve (colour jet)
A chest X-ray makes an image of the heart, lungs, airways, main blood vessels and bones of the chest and spine using a small amount of ionising radiation. It can be used to identify the cause for chest pain, persistent cough or breathlessness. Chest X-rays do not require any preparation, but you will need to remove anything metallic (e.g. jewellery, glasses, a belt) that may affect the image. You will be asked to stand against the image plate and will be asked to hold your breath for a few seconds while the image is taken. The whole process takes approximately fifteen minutes.
