Supraventricular (atrial) ectopic beat (AES, SVES, APB) is a heart beat occurring earlier than normal and originating in either of the atria outside the sinoatrial node.
The P wave of an atrial ectopic beat differs from a normal sinus-originated beat, but the QRS complex is usually similar to that of a normal rhythm.
Epidemiology and clinical significance
Atrial ectopic beats occur both in healthy persons and in patients with heart disease.
In the normal population, they become more common with older age. In the age group over 60 years 20% of the population have more than 100 atrial ectopic beats per 24 hours and 5% have more than 1 000 atrial ectopic beats per 24 hours.
In individuals with a healthy heart, atrial ectopic beats are usually harmless, but in patients with a heart disease or a serious systemic disease their sudden appearance or increase may be a sign of worsening of the underlying disease.
Frequent early atrial ectopic beats (”P-on-T” phenomenon) in ambulatory ECG monitoring may preindicate atrial fibrillation (picture 1).
Investigations and treatment
Patient history taking, careful clinical examination and ECG are an important part of the treatment.
Ambulatory ECG monitoring gives information on the number of extra beats, and it can be used to aid assessing the need for drug therapy.
Other cardiological examinations (echocardiography, exercise stress test etc.) are necessary if the diagnostics or treatment of the patient's primary disease so require or if e.g. findings suggesting a serious heart disease, such as infarct scar, are detected in the ECG.
Although atrial ectopic beats usually are harmless, it is important from the viewpoint of treatment success that the physician does not undermine the annoyance they bring about (good doctor-patient relationship).
In most cases it is sufficient that the benign nature of the arrhythmia is clarified for the patient and the predisposing factors are removed (e.g. coffee, energy drinks, smoking, alcohol, drugs, stress, staying awake late, disorders of thyroid function and electrolyte disturbances).
Regular antiarrhythmic medication may be considered in the treatment of very symptomatic atrial extrasystoles.
In primary care, the drug to be considered in the first place is a beta-blocker. Sometimes also verapamil or diltiazem can be tried.
In specialized care, also flecainide or other anti-arrhythmic agents can be used in the most troublesome cases.
Ablation therapy may be indicated, if the extrasystoles are associated with a severe predisposition to atrial tachycardia or atrial fibrillation.
Treatment response can be evaluated by resting ECG, by Holter monitoring and sometimes also by exercise stress test.