Ectopics

Ectopic beats are extra beats that come out of sync with the normal steady rhythm. They cause the heart to pump earlier than it should do, which is why they may also be called premature beats.

The name "ectopic" means that the electrical spark that causes the extra heart beat comes from outside of the normal conduction system, i.e. it is not from the sinus node. These spontaneous sparks can arise from the muscle fibres in the atriums and adjacent structures such as the pulmoanry veins, causing atrial or supraventricular ectopics, or from the ventricular muscle fibres, causing ventricular ectopics.

Ectopic beats are extremely common - just how common depends on how hard you look. If a simple 12-lead ECG is performed (which takes 12 seconds), 1 in 100 normal people will have an ectopic beat recorded. If a 24-hour Holter is perfomed however, anywhere between 40 and 75 people in 100 will have at least one ectopic beat recorded. Most of these people will only have a few ectopics in a 24 hour period. It is much less common to have frequent ectopics, i.e.more than 100 in 24 hours. Rarely, alternating normal and ectopic beats can occur for minute or so, a rhythm called ventricular bigeminy

Ectopic beats are often nocturnal, or at least happen in the evening and at times of rest, when the heart rate is slower. Usually ectopics beats will disappear during exercise. Ectopic beats that increase in number during exercise or the immediate post-exercise recovery period may indicate a more serious condition and usually require more in-depth investigation.

The majority of people with ectopic beats are blissfully unaware of them and if discovered it is usually by chance. Some people have a greater degree of heart beat awareness and can feel their ectopics. A common description is being aware of a "missed beat", a "flip-flopping" sensation in the chest or neck, or a brief sensation that the heart has stopped. People don't feel the early, premature beat because the ventricles haven't had time to fill properly and so the ectopic doesn't pump much blood out. What they feel is the compensatory pause, or extra long gap before the next sinus rhythm beat that is due finally arrives. This beat may feel very heavy or strong as the compensatory pause has given the ventricles time to overfill and thus squeeze out more blood than usual.

VPB rhythm strip explanation

The ECG tracing running from left to right shows two normal heart beats (N) followed by a ventricular ectopic beat that is early or premature (E). There is a comenatory pause to allow the heart beat to get back in time before the next normal beat occurs. The red bars above each beat reflect the amount of blood and the strength of pumping.

Sometimes ectopic beats are felt more in certain positions or environments. People may also notice that they are linked to certain foods or drinks and may be more prominant after a large meal. Although sufferers of ectopic beats frequently go on to cut out caffeine there is little evidence that doing so makes the ectopics go away.

When assessing and investigating ectopic beats it is important to determine whether the ectopics are benign (harmless) or whether they are an indication of increased risk of a sustained, dangerous rhythm such as ventricular tachycardia. For the vast majority they are harmless. "Red Flags" that should prompt further investigation include a history of blackouts or rapid palpitations, the presence of other cardiac symptoms such as chest pain or breathlessness, or a family history of sudden cardiac death at a young age. Ectopics that occur in hearts that otherwise appear to be healthy are almost always benign, so a normal 12-lead ECG and echocardiogram is very reassuring. If there are any causes for concern further investigations may include a 24 hour Holter or event monitor, a coronary angiogram or a cardiac MRI scan.

Ectopic beats frequently don't require any treatment other than simple reassurance. People may experience them in patches before they gradually fade away after a few weeks. If they persist and become particularly uncomfortable or intrusive, a course of antiarrhythmic medication may help. It is conventional to start with a betablocker. If this is ineffective, or side effects occur, an alternative in people known to have otherwise healthy hearts would be flecainide.

A tiny minority of people have ventricular ectopics that are so frequent that they acount for 25-50% of the total number of heart beats. This may eventually place some strain on the heart muscle. It is sometimes appropriate to perform catheter ablation to try and abolish the ectopics to protect the heart.

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