Ventricular ectopics (also called ventricular extra-systoles or premature ventricular contractions) are ‘extra beats’ that originate from the lower chamber of the heart i.e. the ventricle. It is a fairly common condition that can be seen in any age group.
The article below should clear up any doubts you have about this commonly encountered condition.
What are ventricular ectopics?
If you remember the normal conduction of electricity through the heart muscle, you will recollect that electricity generated in the sino-atrial node, transmitted through a series of conduction fibers, ultimately reaching the ventricle and helping it contract.
In patients with ventricular ectopics, small generators that are present in the muscle of the ventricle also fire electrical impulses. On the odd occasion, these impulses can cause contraction of the ventricle in between normal beats. This extra contraction is called an ectopic beat.
Why do ectopics occur?
Most cases of ventricular ectopics have no clear cause identified. They are the most common type of rhythm abnormality encountered in clinical practice.
However, ventricular ectopics can sometimes indicate the presence of an underlying heart (or non-heart related) problem. Some of the common causes include –
1. Cardiac causes
- Heart attack
- High blood pressure
- Very slow or very high heart rates
- Heart valve disease (especially mitral valve prolapse)
2. Non cardiac causes
- Low levels of potassium or magnesium in the blood
- High levels of calcium in the blood
- Overactive thyroid gland (hyperthyroidism)
- Drugs such as anti-depressant medication and digoxin
- Illicit drugs such as cocaine
- High alcohol intake
- High caffeine intake
What are the symptoms and signs?
There are no specific symptoms that patients may experience, and many feel perfectly fine and symptom free.
However, those who do have symptoms may notice a ‘sinking feeling’ when the extra beat occurs. Some notice slight breathlessness or ‘sighing’ at the time of the extra beat. The feeling of palpitations is common. Some report it as an occasional ‘thumping’ in the chest.
A few patients experience light headedness; a few experience chest pain. Some may experience a combination of all these symptoms. Patients can also experience a great deal of anxiety due to these extra beats.
On clinical examination, a missed beat can be easily felt in the pulse.
What are the tests needed?
Blood tests can help determine if there is any problems with the levels of electrolytes (salts) in the blood. Thyroid function testing may also be performed.
An electrocardiogram can help determine the nature of the extra beat. In some patients, the extra beats may arise from different parts of the ventricle. This is called ‘multi-focal’ extra beats.
An echocardiogram can help determine the presence of any problems with the structure of the heart muscle and the valves.
In patients in whom the symptoms are typical of extra beats, but the ECG is normal, a holter test can be extremely helpful. Holter tests are very sensitive in picking up abnormal rhythms, but can sometimes be normal if a patient does not experience any extra beats on the day it is recording the heart beat. If the suspicion of extra beats is high, the doctor may arrange an extended recording of the heart beat (called an event recorder).
An exercise tolerance test (treadmill test) may be performed if there is concern that there is a problem with the circulation to the heart.
Patients who are experiencing troublesome symptoms may need certain special tests. Electrophysiological studies is one such test that can help find the origin of the extra beats so that treatment can be given to get rid of them.
Types of ventricular ectopics
There are a number of different types of ventricular ectopic beats that are classified in different ways.
1. Depending on the site of origin
- Unifocal – Extra beats that arise from one point in the ventricle
- Multi-focal – Extra beats that arise from multiple points in the ventricle
2. Depending on the number of extra beats
- Occasional – Less than 10 extra beats per hour
- Frequent – More than 10 extra beats per hour
3. Depending on the relationship to normal heart beats
- Bigeminy – Normal and extra beats alternate with each other
- Trigeminy – Every third beat is an extra beat (2 normal beats, then one extra beat)
- Quadrigeminy – Every fourth beat is an extra beat
- Couplet – 2 extra beats back to back
- Non – sustained ventricular tachycardia – 3 or more extra beats back to back
How are ventricular ectopics treated?
Patients who do not have any symptoms do not need any treatment. Simple reassurance is sufficient. The odd extra beat is completely harmless and is not life threatening in any way.
Triggers such as caffeine and alcohol must be avoided.
In patients who are having multiple extra beats, or in those who are experiencing symptoms, medication such as beta-blockers can be helpful. If beta blockers do not work, amiodarone may be used.
Electrophysiological studies and radiofrequency catheter ablation are reserved for patients who do not respond to lifestyle changes and medical therapy.
A small number of patients may need to have a special pacemaker (called implantable cardioverter defibrillator, or ICD) implanted.
What is the future like?
Ventricular extra beats that are only a few in number and not producing any symptoms have a good long term prognosis if the structure of the heart is normal.
Those that have multiple extra beats may be at risk of developing weakening of the heart muscle. However, this is rare.
In patients who have structural heart disease and extra beats, there is a risk of sudden cardiac death. It is important that advice be sought from a cardiologist as soon as possible.