Your heart rate is controlled by a complex electrical system within the heart muscle which drives it to go faster when you exert yourself and slower when you rest.  A number of conditions can affect the heart rate or rhythm.  Heart rate simply refers to how fast your heart is beating.  Heart rhythm refers to the electrical source that is driving the heart rate and whether or not it is regular or irregular.

As some types of arrhythmias can cause you to faint without warning, your doctor may restrict your driving until the condition is controlled.

Some common terms

• Sinus rhythm is the normal rhythm
• Arrhythmia means abnormal rhythm
• Fibrillation means irregular rhythm or quivering of one part of the heart
• Bradycardia means slow heart rate
• Tachycardia means fast heart rate
• Paroxysmal means the arrhythmia comes and goes

Tachycardia

The most common form of this is atrial fibrillation.  This is where your heart rhythm is irregular and often too fast.  Symptoms include fatigue, palpitations (where you are aware of your heart racing or pounding), dizziness and breathlessness.

Other tachycardias include supraventricular tachycardia  (SVT)  or ventricular tachycardia (VT).  These have similar symptoms as atrial fibrillation but can also cause you to lose consciousness (faint).

Bradycardia

The most common form of this is called heart block.  This is because messages from the electrical generator of the heart don't get through efficiently to the rest of the heart and hence it goes very slowly or can pause.  Symptoms of the heart going too slowly include feeling tired, breathless or fainting.

Tests

Tests to diagnose what sort of arrhythmia you have include an electrocardiogram (ECG).  This trace of the heart's electrical activity gives the diagnosis of the source of the arrhythmia. This is often normal at rest and more extensive testing is needed to try and catch the arrhythmia especially if it is intermittent.

an Ambulatory ECG. This can be performed with a Holter monitor which monitors your heart for rhythm abnormalities during normal activity for an uninterrupted 24-hour period. During the test, electrodes attached to your chest are connected to a portable recorder - about the size of a paperback book - that's attached to your belt or hung from a shoulder strap. Another form of ambulatory ECG test is an Event recorder which covers 1-2 weeks.  You wear a monitor (much smaller than a Holter monitor) and if you have any symptoms, such as dizziness, you press a button on a recording device which saves the recording of your heart rhythm made in the minutes leading up to and during your symptoms.  Because you can wear this for a longer period of time it has a higher rate of catching your abnormal rhythm.

Treatment

Most treatments for tachycardias consist of medication to stop the abnormal rhythm or make it slower if and when it occurs.  Atrial fibrillation, if you have other problems, can increase your risk of stroke so blood-thinning medication is often used as well.

If you have bradycardia you may be referred to the electrophysiology cardiology team for a pacemaker.  This is a small operation where a battery powered device is placed under the skin with wires that lead to your heart and provide it with electrical stimulation to prevent it from going too slowly.  

This refers to narrowing of the arteries that supply blood to the heart muscle. The heart, like all other organs in the body, needs a constant supply of oxygen and energy.  Narrowed arteries are unable to keep up with the demand needed to supply the heart muscle with blood. This can cause damage to the heart muscle if prolonged. 

The most common symptom of this problem is chest pain that occurs when you exert yourself (angina).  Typical angina chest pain is a heavy sensation in your chest associated with shortness of breath.  It sometimes radiates to your arms and can make you feel like being sick, dizzy or sweaty.  Not everybody experiences the same sensation and any one of those symptoms can represent angina.  If your GP thinks you may have angina they will refer you for an assessment to plan treatment.

Heart Attack (Myocardial Infarction)

If an attack of angina lasts for more than 20 minutes then you may be having a heart attack.  This is when a piece of the heart muscle has been deprived of oxygen for so long that it can die, resulting in permanent damage to your heart and in some cases death.  There are treatments available in hospital that can prevent heart attacks and save lives so if you have chest pain or symptoms of angina that last for more than 20 minutes you should call an ambulance and go to hospital as soon as possible.

Am I likely to have cardiovascular disease?

There are several risk factors that are scientifically proven to be associated with this disease.  However even if you don’t have any of the following it could still happen to you.

• You are more likely to have cardiovascular disease if you have any of the following:
• Are or have been a smoker
• Diabetes
• High blood pressure
• High cholesterol
• A family history of the disease
• Are older (your risk increases as you get older)

Treatment consists of medications to protect the heart and its blood vessels.  These include aspirin which makes the blood less sticky and prone to clots, medication to lower your cholesterol (even if it isn’t very high this is still helpful), medication to make your heart go slower and to open the blood vessels.  You will be given a nitro lingual spray to carry with you with instructions of what to do if you have angina.

You will be given advice on diet changes that can protect the heart as well as stop smoking programs.

If you have had a heart attack you will be offered cardiac rehabilitation classes with a trained physiotherapist.

Depending on tests you may have procedures offered to surgically correct the narrowed blood vessels.

The cardiology department and your GP often share follow-up for this condition.

Heart failure refers to the heart failing to pump efficiently.  There are many diseases that cause this including cardiovascular disease, high blood pressure, viral infections, alcohol, and diseases affecting the valves of the heart.  When the heart is inefficient a number of symptoms occur depending on the cause and severity of the condition.  The main symptoms are tiredness, breathlessness on exertion or lying flat, and ankle swelling.  Doctors often refer to oedema, which means fluid retention usually in your feet or lungs as a result of the heart not pumping efficiently.

Tests looking for possible causes of heart failure include:

• Chest X-ray
• Electrocardiogram (ECG)
• Echocardiogram (Cardiac ultrasound)
• Angiogram

Treatment

You are likely to have several medications over time, started and monitored by your cardiologist and GP.  These include medication to control the amount of fluid that builds up (diuretics), medication to protect your heart and slow it down as well as to thin your blood.  You will often be referred to a dietician or given advice about restricting the amount of fluid and salt you take as this can contribute to symptoms. You can also be involved in cardiac rehabilitation programmes run by trained physiotherapists.  You will be given reading material to learn more about your disease.

The cardiologist and your GP usually share follow-up for this condition.

Your heart consists of 4 chambers that receive and send blood to the lungs and body.

Disorders affecting valves can either cause stenosis (a narrowing) or regurgitation (leakage after the valve has closed).  Depending on what valve is involved and how severe the damage is it may result in symptoms of heart failure (see above), as it makes the heart pump inefficiently.

Suspicion of a heart valve problem is usually picked up by your doctor when they listen to your heart and hear a murmur.  A murmur is heard with the stethoscope and is turbulence of blood flow that occurs through a narrowed or leaky valve.  Not all heart murmurs mean serious problems but are best investigated further.

The echocardiogram is the main test to diagnose what valve is involved and how severe it is.

Treatment depends on the type and severity of the valve lesion. You may simply be monitored over years to see if anything changes. Some conditions require medication to thin the blood or treat any complicating heart problems. You may be referred to a heart surgeon for consideration of a valve replacement or dilatation of a narrowed valve.