They are extra heartbeats that occur outside the physiological rhythm of the heart and can cause unpleasant symptoms.
Extraystoles are also known as missed heartbeats, “hypocardia,” or palpitations , and are medically considered a form of cardiac arrhythmia .
In most cases, the extra heartbeat can hardly be felt, or only very faintly. It is the next regular heartbeat that occurs later and stronger, which is perceived as the missed heartbeat.
The affected person can then worry about possible heart disease.
Frequent and apparently idiopathic premature ventricular contractions are generally considered a benign condition that can be managed with conservative measures. B-blockers are usually very effective.
Radiofrequency catheter ablation therapy has generally been reserved for patients with frequent PVCs whose quality of life is disturbed by bothersome symptoms or patients with sustained ventricular tachycardia.
It is relatively common for cardiovascular physicians to see patients with frequent premature ventricular contractions. They can appear in patients without overt cardiovascular disease, in which case the pathogenesis can be considered idiopathic.
However, although they are mostly asymptomatic, PVC patients can experience disturbing symptoms and there are times when the presence of PVC signifies susceptibility to more sinister arrhythmias, especially when heart disease is present.
Premature ventricular contraction in certain patients is triggered by the same mechanisms that lead to ventricular tachycardia, which can be cured with catheter ablation.
Appropriate clinical evaluations and investigations are important in evaluating patients so that effective treatment can be directed.
What are the symptoms of extrasystoles?
Typical symptoms of extrasystoles that cause a disturbance in regular heart rhythm include the following:
- Heartbeats that feel like irregular and stronger than normal, or too strong, with a feeling of the heart beating in the throat.
- Feeling restless, anxious, or panicky; perspiration.
- Chest pain.
- Feeling of shortness of breath.
- Upset stomach or increased desire to urinate.
- Headache or nausea.
Always see a doctor or cardiologist if these symptoms occur in relation to a pre-existing underlying heart condition.
What causes extrasystoles?
Among the causes of extrasystoles in healthy individuals are:
- Fatigue .
- Stress .
- Physical and mental tensions.
- Potassium or magnesium deficiency.
- Excessive consumption of alcohol, nicotine, or coffee.
However, extrasystoles can also be a symptom of heart disease, such as:
- Coronary heart disease.
- Inflammation of the heart muscle.
- Valve defect.
- Heart failure.
- Hyperthyroidism .
Prevalence and prognosis
Premature ventricular contractions have been described in 1% of clinically normal persons detected by a standard ECG and in 40-75% of apparently healthy persons detected by 24-48 hour ambulatory ECG (Holter) recordings.
Kennedy et al demonstrated that frequent (> 60 / h or 1 / min) and complex PVCs could occur in apparently healthy subjects, with an estimated prevalence of 1% to 4% of the general population. In addition to the demos, they are frequent and complex.
Ventricular ectopy could occur in healthy subjects, they also showed that it could be associated with a benign prognosis.
In addition, both the incidence and complexity of PVCs increase in almost all heart diseases and could be as high as 90% in coronary artery disease and dilated cardiomyopathy.
Other studies, such as MRFIT and data from the Framingham Heart Study, have linked the frequent occurrence of PVC with an increased risk of sudden cardiac death and death from any cause.
However, these studies have been criticized for a lack of rigorous measures to exclude underlying heart disease, which can cut the death outcome in half.
These irregularities did not interfere with normal lifespan when they were occasional, but they were assumed to be an ominous prognosis if they were frequent.
This was shown to be the case in more recent times where patients who had had a myocardial infarction were more prone to sudden death if they had frequent PVCs.
However, recent studies have documented that LV dysfunction in patients with frequent PVCs could recover after removal of PVCs by medical treatment or catheter ablation therapy in certain cases.
The duration and morphology of PVCs are highly variable and depend on the place of origin, the presence of structural heart disease, and treatment with antiarrhythmic drugs.
In general, the duration of the QRS is greater than 120 ms, because the propagation of the activation occurs from a ventricle to the contralateral one to the nonspecialized myocardium.
However, when activation comes from one of the fascicles through a specific conduction system, both ventricles could be activated “synchronously”, which can result in a QRS complex of less than 120 ms.
Premature ventricular contractions can be classified in several ways, depending on:
- The docking interval (early and late).
- The duration of the QRS (wide and narrow).
- The complexity.
The morphology of PVCs is of great importance in patients susceptible to being treated by catheter ablation, since the 12-lead ECG can identify the origin of PVCs with a certain degree of precision.
As a general rule, PVCs originating from the left ventricle have a right bundle branch block morphology, and PVCs originating from the right ventricle have a left bundle branch block pattern.
Frequent PVCs can also be seen in patients with hypertension.
In the MRFIT population cohort of more than 10,000 men aged 35 to 57 years, the level of systolic blood pressure was related to the prevalence of PVC.
The most recent data in the ARIC (Atherosclerosis Risk in Communities) study of more than 15,000 white and African American men and women presented widespread findings showing frequent or complex PVCs that are also associated with hypertension.
The Framingham study has indicated that patients with left ventricular hypertrophy by electrocardiographic criteria have a higher risk of sudden death and acute myocardial infarction than subjects with a normal heart.
The ARIC study also demonstrated that the prevalence of PVC increases with electrocardiographic increases in left ventricular mass.
In some cases, PVCs may be the first manifestation of underlying structural heart disease. For this reason, in all patients with PVC, the physician should take a detailed history of 12-lead EKG and chest radiograph.
Although the relationship between common PCP originating in the ventricular outflow tract and arrhythmogenic right ventricular cardiomyopathy was once suggested.
The indication for an EKG-Holter recording, a stress test, or an echocardiogram depends on whether PVCs persist after the initial evaluation of suspected structural heart disease or the development of complex forms of ventricular arrhythmias.
For more than 20 years, it has been accepted that the presence of PVC in the absence of structural heart disease carries a favorable benign prognosis, even when it occurs frequently.
For this reason and due to the proarrhythmic potential of antiarrhythmic drugs (see below), the clinician does not need to treat PVCs in this clinical setting, except when PVCs are responsible for many symptoms.
However, in some cases, very common PVCs can cause ventricular dilation and dysfunction (tachycardiomyopathy), the latter being an indication for treatment (ablation or antiarrhythmic drugs), even in the absence of symptoms.
In any case, the clinical importance of frequent PVCs in patients without LV dysfunction is still unclear.
The prognostic importance of PVCs in ischemic heart disease is less benign. In fact, in patients who have suffered a myocardial infarction, the presence of PVC has been associated with an increase of up to 3 times the risk of sudden death.
There are conflicting results regarding the significance of PVCs in strength tests. Frolkis et al, demonstrated that the presence of frequent PVCs during recovery from exercise tests is a better predictor of the risk of sudden death than the isolated presence of PVC achieved during exercise.
Caffeine is a central stimulant that can increase sympathetic activity.
Clinical impression and anecdotes often associate arrhythmias with caffeine, alcohol, and tobacco use has been widely practiced in the management of patients with palpitations despite the relative lack of direct evidence.
Animal studies have shown that caffeine administration in high doses could induce and increase the frequency of PVC.
There are some epidemiological data with an association between PVC activity and caffeine intake, but experimental studies in humans have not produced consistent results to establish this link.
The thinking behind the need to suppress PVCs was studied in the Cardiac Arrhythmia Suppression Trial (CAST). (17) This study suggests that suppressing asymptomatic or minimally symptomatic PVCs after myocardial infarction would reduce arrhythmic death.
The authors concluded that treatment with Flecainide and Encainide was an independent risk factor for arrhythmic death, cardiac death, and non-arrhythmic mortality. This excess mortality was independent of the post-AMI time.
This additional study highlights the proarrhythmic effect of these drugs in heart disease patients and questions the idea of using drugs simply to suppress PVCs.
PVCs originating from RVOT have been associated with malignant ventricular arrhythmias.
The ability of common PVCs originating from a focal source to trigger idiopathic ventricular fibrillation (VF) in apparently normal hearts was first reported by Haissaguerre et al.
PVCs were assigned to sites in the RVOT and also along the distal Purkinje system in the left and right ventricles.
Catheter ablation has been shown to be effective in acutely eliminating EBVs and reducing the incidence of increased VF recurrence.
Similar triggers have been shown in selected patients with Brugada and Long QT syndromes with a report of successful PVC removal with catheter ablation.
Further studies in large numbers of patients with longer follow-up are required to assess the full prognostic benefit of this approach.
Progressive PVCs are induced with exercise or stress, which can cause syncope or sudden death with polymorphic VT or VF. Treatment is usually with blockers and ICD implantation.
The decision to treat or not to treat an extrasystole ventricular also depends, in the first place, on the benign or severe nature of the disorder and on whether there is an underlying heart disease.
The results of 24-hour Holter monitoring, exercise tolerance tests, and ultrasound and clinical examinations will define the pathological character of an extrasystole ventricular and indicate any underlying heart disease.
Electrophysiologic examination with programmed pacing should be reserved for so-called fatal arrhythmia cases, such as attacks of sustained ventricular tachycardia. Ischemic heart disease is by far the most common cause of premature ventricular beats.
The two main risks of sudden death after myocardial infarction are due to left ventricular dysfunction and complex repetitive ventricular extrasystoles. as well as attacks of ventricular tachycardia.
Cardiac patients with these disorders should be treated urgently with antiarrhythmics. Isolated monomorphic ventricular extrasystoles are also treated in cardiac patients at risk if their rate is greater than 10 per hour, as measured by 24-hour Holter monitoring.
In the absence of underlying heart disease, the therapeutic indications are much less defined. Approximately five percent of subjects in a normal population have premature ventricular beats, the frequency of which, however, rarely exceeds 100 per 24 hours.
Repetitive phenomena are only seen in 10% of cases. Ventricular tachycardia attacks are almost never seen. Ventricular extrasystoles that develop in apparently normal hearts, but do not meet the above criteria, can be considered abnormal.
Recommendations for healthy people
In healthy individuals, there is generally no need to treat extrasystoles.
Often times, it may be enough to simply make a few lifestyle changes, such as cutting down on alcohol and cigarettes, relieving stress, playing more sports, and getting enough sleep.
Also, heart palpitations can sometimes be counteracted by taking mineral supplements, although you should always consult your doctor before taking any nutritional supplement.
Extraystoles can be treated with medications, eg. Eg taking mineral supplements or stabilizing the heart rate with beta blockers.