What are Cardiac Arrhythmias?
Normal sinus rhythm can be defined as a regular heart rate of between 60 and 100 beats per minute. Any deviation from this, by definition is an arrhythmia.
The heart is a 4 chambered muscular pump, about the size of a person’s fist, and is made of special cardiac muscle. The chambers contract and relax in a regular sequence, and this action is controlled by an electrical impulse, which originates in the upper chamber (atrium) of the heart, in the Sino-atrial Node. The electrical current travels down regulated pathways at a specific speed (The link below to “Conduction pathways in the heart” explains the mechanism of conduction).
If there is a disorder of the system at any specific point, (i.e. where the impulse originates) or any problem with the path of conduction or if the pathway itself is abnormal or extra to the usual pathway or if the rate is abnormally fast or slow, an arrhythmia is said to occur.
Arrhythmias may be symptom-less.
Perceived arrhythmias (or irregularities in the heart rate or rhythm) may be fast (tachycardia) or slow (bradycardia), they may arise because of blocks or delays in the conduction system and may be supraventricular (arising above the ventricle) or ventricular (arising in the ventricles).
Any part of the heart muscle can act as a “pacemaker”, (that is, is capable of starting a beat) and in some situations may take over as the heart’s pacemaker and set off an abnormal heartbeat (or series of beats).
Arrhythmias may occur in conjunction with other conditions such as ischaemic heart disease or cardiomyopathy and can be worsened by conditions such as thyroid disease or anaemia.
The most common type of recurrent arrhythmia is Atrial Fibrillation. The atria “quiver” and the ventricles contract irregularly following a normal conduction process through the atrioventricular node. The pulse is irregular. Blood tends to pool in the atria and patients are susceptible to strokes, caused by a bit of clot breaking off (emboli), and travelling to the brain.
Atrial fibrillation often occurs in the elderly. It can be caused by:
- an over active thyroid (hyperthyroidism),
- heart valve disorders,
- coronary artery disease,
- alcohol excess,
- rheumatic fever,
- high blood pressure (Hypertension).
If evidence suggests that the customer has heart failure, which may have resulted from an arrhythmia then go to Heart Failure guidance.
If evidence suggests that the customer has had a stroke, which may have resulted from an arrhythmia then go to Stroke guidance.
