![]() ![]() More recent data in the Atherosclerosis Risk in Communities (ARIC) Study (13) of more than 15,000 white and African- American men and women presented extended findings that showed frequent or complex PVCs that are also associated with hypertension. (12) In the MRFIT population cohort of over 10, 000 men aged 35-57 years, the level of systolic blood pressure was linked with the prevalence of PVCs. As a general rule, PVCs originating in the left ventricle have right bundle branch block morphology, and PVCs originating in the right ventricle have a left bundle branch block pattern.įrequent PVCs can also be observed in patients with hypertension. The morphology of PVCs is of great importance in patients susceptible to being treated by catheter ablation because the 12-lead EKG can identify the origin of PVCs with a certain degree of precision. Premature ventricular contractions can be classified in various ways, depending on: 1) coupling interval (early and delayed) 2) QRS duration (wide and narrow) 3) morphology and 4) complexity. However, when activation comes from one of the fascicles through a specific conduction system, both ventricles could be activated 'synchronously', which may result in a QRS complex of less than 120 ms. In general, QRS duration is mostly longer than 120 ms because the activation spread occurs from a ventricle to the contralateral one through the nonspecialised myocardium (figure 1). The length 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. Nevertheless, recent studies have documented that the LV dysfunction in patients with frequent PVCs could recover after elimination of the PVCs by medical treatment or catheter ablation therapy in certain cases. This was shown to be so in more recent times where patients who have had a myocardial infarction were more prone to sudden death if they had frequent PVCs (5). These irregularities did not interfere with normal lifespan when they were occasional, but an ominous prognosis was implied if they were frequent. However, these studies have been criticised for the lack of rigorous measures to exclude underlying heart disease confounded, which can halve the outcome regarding death. (2,3) Other studies such as MRFIT (4) and data from the Framingham Heart Study (5) have linked the frequent occurrence of PVCs with an increased risk of sudden cardiac death and death from any cause. 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 1–4% of the general population.(1) Further to demonstrationg that frequent and complex ventricular ectopy could occur in healthy subjects, they also showed it could be associated with a benign prognosis.Īdditionaly, both the incidence and complexity of PVCs is increased in almost all heart disease, and could be 90% in coronary artery disease and dilated cardiomyopathy. Premature ventricular contractions have been described in 1% of clinically normal people as detected by a standard ECG and 40–75% of apparently healthy persons as detected by 24–48 hour ambulatory (Holter) ECG recordings. ![]() ![]() They may appear in patients without any overt cardiovascular disease, in which case pathogenesis can be considered idiopathic. However, although largely asymptomatic, patients with PVCs can experience upsetting symptoms, and there are occasions when the presence of PVCs signifies susceptibility towards more sinister arrhythmias, especially when heart disease is present. Premature ventricular contraction in certain patients is triggered by the same mechanisms that give rise to ventricular tachycardia, which may be cured with catheter ablation. Appropriate clinical evaluation and investigations are important in assessing patients so that effective treatment can be targeted. It is a relatively common occurrence for cardiovascular clinicians to see patients with frequent premature ventricular contractions. ![]()
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