Palpitations: Symptoms, types, causes, diagnosis, treatment
Palpitations is the feeling that happens when someone feels an abnormality in the normal beating of the heart. These palpitations can be an isolated extra beat, or they can run together and last for prolonged periods of time. Each part of the heart has the potential to be irritable and cause an extra beat to occur. As well, short circuits in the electrical conduction system of the heart can cause "runs" of abnormal firing.
Every muscle cell in the heart has the potential to generate an electrical signal that can spread outside the normal electrical pathways and bundles to try to generate a heart-beat. If the sino-atrial (SA) node fails, then other cells in the atrium try to take over. If they fail, then the atrio- ventricular (AV) node can take over, but at a lower rate of about 40 beats per minute. And as the final backup, the ventricle itself can generate electricity but at a much slower rate of about 20 beats per minute.
Types of Palpitations
Extra heart-beats are normal and most people are unaware that they have occurred. Every muscle cell in the heart has the potential to generate an electrical signal that can spread outside the normal electrical pathways and bundles to try to generate a heart beat. Many extra beats are normal variants and can be nothing more than an occasional irritant, but others can be dangerous - either acutely or chronically. Extra beats that originate in the atrium tend not to be as serious as those that come from the ventricle.
Abnormal heartbeats are classified by the location where they originate, if they happen occasionally or if they are clustered in runs, and if they resolve by themselves (self-limiting).
Conditions causing palpitations include:
- Premature atrial contractions (PAC)
- Premature ventricular contractions (PVC)
- Supraventricular tachycardia (SVT)
- Atrial fibrillation and flutter
- Ventricular tachycardia (V tach) and fibrillation
- Specific types of palpitations may be due to structural abnormalities in the heart.
- Women who are pregnant often experience palpitations but usually no dangerous rhythm disturbance is present.
The heart needs its normal environment to work well. This is especially true for the heart's electrical system. Changes in electrical conduction may lead to a decreased ability of the heart to pump blood.
From within the body, abnormal levels of electrolytes like potassium, magnesium, and calcium can cause palpitations. Anaemia and hyperthyroidism are also potential causes of palpitations.
Many of the substances that we put into our body can cause palpitations by appearing to act like adrenalin on the heart and make it irritable. Common stimulants include:
Palpitations can be associated with an isolated "skipped beat" sensation or, if the palpitations are prolonged, there can be a feeling of fluttering or fullness in the chest. Sometimes patients describe a marked fullness in their throat associated with shortness of breath, and it may be difficult to decide if the fullness is due to palpitations or due to angina. This is especially so if the palpitations have subsided and are not present when the affected person seeks medical care. Prolonged episodes can be associated with chest pain, shortness of breath, sweating, and, nausea and vomiting. Some types of heart rhythm problems can cause light-headedness or even passing out ( fainting).