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Ventricular Premature Beats: Difference between revisions
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{{Chapter|Ventricular Arrhythmias}} | {{Chapter|Ventricular Arrhythmias}} | ||
[[Image:Rhythm_ventricular_premature.png|thumb| The arrow indicates a ventricular extrasystole (VES).]] | [[Image:Rhythm_ventricular_premature.png|thumb| The arrow indicates a ventricular extrasystole (VES).]] | ||
[[Image:Rhythm_bigemini.png|thumb|Bigemini: every sinus beat is followed by a ventricular extrasystole]] | |||
[[File:E000603.png|thumb|This ECG shows frequent premature beats from the right ventricular outflow tract]] | |||
A VPB is an [[Ectopic Beats|ectopic beat]] that originates from the ventricles. VPBs are conducted by the specialized conduction system and therefore are broad. The QRS width is at least > 0.12 seconds, but often very broad at around 0.16-0.20 seconds. The VPB is usually followed by a [[Ectopic Beats|compensatory pause]], however this can be absent in the presence of retrograde conduction through the av-node. | |||
A sequence of three or more extrasystoles is called a [[ | Causes: e.g. ischemia, hypoxia, old scar tissue, idiopathic. Fifty per cent of healthy men have sporadic VPBs. | ||
The origin of the VPB can be derived from its form. An LBTB-configured VPB originates in the right ventricle. An RBTB-configured VPB comes from the left ventricle. The QRS duration of a VPB is > 0.12 seconds and can be as wide as 0.16-0.20 seconds. | |||
'''A sequence of three or more extrasystoles''' is called a [[Ventricular Tachycardia|non-sustained ventricular tachycardia]]. | |||
If more than one VPB is present on the ECG, they can be: | If more than one VPB is present on the ECG, they can be: | ||
*'''monomorphic''': all VPBs have the same configuration and thus have a mutual focus of origin. | *'''monomorphic''': all VPBs have the same configuration and thus have a mutual focus of origin. | ||
*'''multiformic''': the complexes have different configurations. | *'''multiformic''': the complexes have different configurations. | ||
*'''bigemini''': every sinus beat is followed by a ventricular extrasystole. | |||
*'''trigemini''': every second sinus beat is follow by a ventricular extrasystole. | |||
VPBs are associated with numerous cardiac diseases (e.g. structural heart disease, ischemia, congenital arrhythmias, pulmonary disease). | |||
However, VPBs are also relatively common in patients without known heart disease. The importance of VPBs for prognosis is controversial. A study by Abdalla et. al <cite>Abdalla</cite> followed 15.637 apparently healthy men aged 35 to 57 years. The prevalence of VPBs was 4.4%. In a subgroup of patients with frequent (2 or more uniform VPCs every 2 minutes) and complex VPBs (multiforms, pairs, runs, R-on-T) the risk of sudden cardiac death was 4.2. In the Framingham study 12% of men and 33% of women without clinically evident coronary heart disease had frequent (>30 VPBs per hour) or complex VPBs. In men, this was associated with a two fold increase of death. However, in another study asymptomatic patients had a good prognosis. <cite>Kennedy</cite> Therefore, probably sporadic VPBs are relatively benign, whereas frequent and complex VPBs are reason for further examination. | |||
==References== | |||
<biblio> | |||
#Kennedy pmid=2578212 | |||
#Framingham pmid=1280018 | |||
#Abdalla pmid=3673904 | |||
</biblio> | |||