CARDIAC RHYTHM DISORDERS
The sinoatrial (SA) node controls the heartbeat with electrical impulses. It is the heart's natural pacemaker. Cardiac rhythm disorders, otherwise known as arrhythmias, are conditions which affect the normal heart rate making it beat too fast, too slow or irregularly. They can be caused by a previous heart attack, valvular heart disease, high blood pressure, coronary artery disease and congenital heart disease.
The different types of arrhythmias include premature atrial contractions, supraventricular tachycardia, premature ventricular complex, ventricular tachycardia, ventricular fibrillation, sick sinus syndrome, atrial flutter and the most common type of arrhythmia, atrial fibrillation. While many arrhythmias don't cause health problems, the symptoms can affect the quality of life, and more severe cases may require medical management as when left untreated, they can eventually lead to stroke, heart attack, heart failure, fainting spells or sudden death. It may be necessary to see a cardiologist if you are experiencing any of the following symptoms:
- racing and irregular heartbeat
- heart palpitations
- lightheadedness or dizziness
- chest pain or discomfort
Diagnosis & Treatment
If you suspect you may be suffering from a cardiac rhythm disorder, Dr Ho may do a physical exam followed by a range of tests to diagnose a specific type of arrhythmia. These diagnostic tests may include an electrocardiogram (ECG) or exercise stress test to evaluate the electrical activity generated by the heart when it is at rest and when exercising. This will measure the rhythm, length of heartbeats and identify abnormalities with the rhythm. A portable electrocardiogram (ECG) machine may also be used to monitor the heartbeat continuously over a period of time; this is called a Holter monitor. Dr Ho may also recommend an echocardiogram or diagnostic cardiac ultrasound, which is an ultrasound of the heart to give a better image of the structure of the heart, including the chambers and valves.
A variety of approaches can be taken in treating and managing arrhythmias. Depending on the severity of the condition, monitoring may only be needed while others may require urgent treatment.
Treatment of arrhythmias may include medications to slow a rapid heartbeat, prevent blood clots through the use of blood thinners and stabilisation of regular heart rhythm. Implantable devices such as a pacemaker or an ICD (implantable cardioverter-defibrillator) may also be used to maintain normal heart rhythms.
Certain kinds of arrhythmias can also benefit from cardioversion. A cardioversion is done by sending electric shocks to your heart through electrodes placed on your chest. It is done to try to reset the heartbeat. In some cases, arrhythmias may need to be treated with a technique called ablation which involves the cauterisation of a small area of tissue to block abnormal electrical signalling pathways in the heart which would be performed by an electrophysiologist as part of management of cardiac rhythm disorders.