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Signs and symptoms of bradycardia
Some types of bradycardia produce no symptoms, and others may cause dizziness, weakness or fainting (syncope).
Sick Sinus Syndrome occurs when the hearts natural pacemaker, the SA node fails, causing an irregular heartbeat. Patients with sick sinus syndrome may experience a slow heartbeat (bradycardia), a fast heartbeat (tachycardia) or heartbeats that swap between fast and slow (brady–tachy syndrome or tachy–brady syndrome). Patients may experience dizziness, tiredness, weakness or fainting (syncope). Although, it is more common in elderly people it can occur in children, often after cardiac surgery.
Heart block (atrioventricular block or AV block) occurs when electrical impulses are slowed or blocked as they travel from the top chamber of the heart (atria) through the atrioventricular node (AV node) into the bottom chambers (ventricles). The symptoms and treatments for heart block depend on its severity, the different types of heart block and the treatment options available are explained below.
First–degree heart block occurs when the electrical impulses slow as they pass through the AV node however, all impulses reach the ventricles. First–degree heart block rarely causes any symptoms, and is often found in athletes. No other treatments are generally necessary.
Type I second–degree heart block occurs when the electrical impulses are delayed to a greater extent with each heartbeat until a beat is skipped entirely and the cycle then repeats itself. This may cause dizziness and other symptoms. In such cases, a pacemaker may be required.
Type II second–degree heart block occurs when some of the electrical impulses from the SA node are unable to reach the ventricles, for example every third or fourth impulse. This is usually because of an underlying disease. A pacemaker may be required to control and regulate the heart rhythm.
Third–degree heart block (complete heart block) occurs when no electrical impulses reach the ventricles, this is usually as a result of underlying disease or medications. In the absence of any electrical impulses from the atria, the ventricles produce impulses on their own; these are called ventricular escape beats. However, these heartbeats are usually slow and the patient may feel very unwell. Sometimes the patient remains relatively well and a pacemaker can be implanted after a few days. Occasionally, this condition needs to be treated more quickly and if a pacemaker cannot be implanted immediately, the doctors will put a temporary pacemaker wire into the heart to keep the heart pumping regularly until the permanent pacemaker system is implanted.
Treatment options for bradycardia
Commonly symptomatic bradycardia is treated by discontinuing any medications that slow the heartbeat and treating any underlying conditions and/or by implanting a permanent pacemaker.
A pacemaker is a small device, approximately the size of a fifty pence piece used to detect and treat slow heart rhythms, it is implanted beneath the skin below the collarbone and connected to a pacing wire placed inside the heart. The pacemaker fires s a small electrical impulse to stimulate the heart to beat when it is going too slowly.
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