A ventricular ectopic beat refers to an extra heartbeat originating from the left or the right ventricle. QRS complex is wide and different from that during normal rhythm.
The most important factor when investigating the aetiology of ventricular ectopic beats (VEs) is to establish the possible presence of structural heart disease. Should structural heart disease be identified, treatment should firstly be aimed towards the management of this condition and only secondarily towards the arrhythmia itself.
VEs of a healthy heart are a benign phenomenon, and the need for treatment depends on the sensations caused by the VEs. The mere knowledge that the condition is benign and the symptoms are not caused by a heart disease is enough to reassure most patients.
However, frequent VEs associated with heart disease (e.g. recent myocardial infarction, heart failure) and hereditary ion-channel disorders (e.g. long QT syndrome, polymorphic catecholamine-sensitive ventricular tachycardia) may be predictive of serious arrhythmias and require the involvement of a cardiologist.
Prevalence and symptoms
The frequency of VEs varies according to the patient's underlying disease and the state of mental alertness.
During 24-hour ECG recordings and clinical exercise tolerance testing, VEs are noted in about half of all healthy individuals and more frequently in association with heart disease.
Typical predisposing factors include stress, lack of sleep and excessive intake of coffee, energy drinks or alcohol.
The most common symptoms are momentary palpitations and various chest sensations (feeling the heart like doing a somersault in the chest or skipping a beat).
Episodes of syncope (and presyncope) are rare. Such episodes are suggestive of a serious underlying disease and always warrant thorough cardiological investigations.
Investigations
It is essential to verify the diagnosis and exclude the presence of structural heart disease.
Diagnosis should be based on the patient's history, clinical examination and a 12-lead ECG. Usually the only laboratory investigations needed are a blood count, electrolytes and thyroid function tests.
If nothing suggestive of a heart disease shows up in these investigations the patient may be told that the VE's are of a benign nature and no further cardiological investigations are needed.
The most frequently needed follow-up studies include continuous ambulatory ECG recording, echocardiography and exercise tolerance testing.
Continuous ambulatory ECG recording can be used also for determining the number of extrasystoles and for evaluating the treatment response.
Echocardiography is the primary investigation for assessing how dangerous the predisposition to ventricular ectopic beats is. It is indicated when basic investigations suggest a heart disease (e.g. a murmur), or a large number of monomorphic ventricular ectopic beats (> 3 000-5 000/24h) or abundant polymorphic ventricular ectopic beats are detected in Holter monitoring.
An exercise stress test or coronary CT angiography is indicated, if the sensations of arrhythmia occur especially during exertion or if there is a suspicion of coronary heart disease.
Invasive investigations (coronary artery contrast medium imaging, electrophysiological studies) should be considered if the VEs are associated with serious heart disease or the patient gives a history of syncope.
Treatment
Ventricular ectopic beats of a healthy heart
VEs of a healthy heart are usually harmless and the need for treatment depends on the patient's symptoms.
Asymptomatic VEs require treatment in exceptional cases only.
Very abundant VEs (>20 000 beats / 24 hours) may cause tachycardia myopathy in the same way as rapid atrial fibrillation.
Drug treatment is usually not needed even in patients with mild symptoms.
It is most important to explain the benign nature of the arrhythmia to the patient.
An attempt should be made at the same time to eliminate any precipitating factors (coffee, energy drinks, alcohol, smoking, stress, lack of sleep, thyroid disorders, electrolyte imbalances). Improving one's physical condition may also be of help.
If the symptoms are severe, a beta-blocker may be tried, if the aforementioned interventions do not help.
Beta-blockers are effective against VE's that originate from stress or exertion.
They are safe to use in primary care as well, but their routine use should be avoided since they may aggravate the condition in situations where the VE's principally occur whilst the heart rate is slow (e.g. during rest, after exercise or at bedtime).
Short-acting products (e.g. propranolol 10-40 mg as needed) are recommended for temporary use. Products requiring once daily dosing (e.g. bisoprolol, metoprolol) are recommended for treatment of a longer duration.
If beta-blockers are contraindicated or achieve a poor response, the calcium-channel blockers verapamil and diltiazem may be tried.
Should a large number of monomorphic VEs be detected in Holter monitoring in a patient with severe symptoms despite life style changes and the above mentioned medication, the patient should be referred to a cardiologist for more specific investigations and for the possible introduction of an anti-arrhythmic drug (e.g. flecainide). Catheter ablation may also be considered.
The VEs most suitable for ablation therapy are frequent (> 5 000 / day) VEs that originate from the right ventricular outflow tract (RVOT).
The morphology of these ectopics resemble that of left bundle branch block and they are strongly positive in the inferior leads (II, III, avF).
Ventricular ectopic beats associated with hereditary arrhythmia disorders
In hereditary arrhythmia disorders (e.g. long QT syndrome [LQTS] Long QT Syndrome (LQTS), catecholaminergic polymorphic ventricular tachycardia [CPVT]) the predisposition to arrhythmias is caused by a congenital ion-channel defect.
The heart is structurally healthy, but due to the ion-channel changes the treatment of ventricular ectopics requires special expertise. These patients should always be referred to an arrhythmia cardiologist for consultation. Close relatives should also be examined.
The cornerstone of treatment in LQTS and CPVT is beta-blocker medication. It must not be stopped without consulting an arrhythmia cardiologist first.
Ventricular ectopic beats associated with heart disease
When treating VEs associated with coronary heart disease or other heart diseases it is most important to treat ischaemia, heart failure or any other underlying condition (e.g. sarcoidosis) that is affecting the heart.
Abundant VEs in a heart disease (including asymptomatic ones) predict sustained ventricular arrhythmias and sudden death. Therefore, these patients should be readily referred to a cardiologist in order to assess the need for invasive investigations and treatment (e.g. an implantable cardioverter defibrillator).
Particularly dangerous are early VEs that fall over a T wave, as well as abundant polymorphic VEs.
Treatment with beta-blockers significantly improves the prognosis in patients with diagnosed myocardial infarction or heart failure caused by ischaemic or non-ischaemic cardiomyopathy.
In mild cases, beta-blocker medication can be stated in outpatient care, but in severe heart failure it is best to start the therapy at a hospital.