WPW is best known for its association with supraventricular tachycardias which are usually initiated by an atrial premature complex
, but can be initiated by ventricular premature complexes
HRT measurements, turbulence onset (TO) and turbulence slope (TS), were calculated in patients and healthy controls that have at least one ventricular premature complex (VPC) in their Holter recordings.
Key words: Autonomic nervous system, heart rate turbulence, ventricular premature complex, rheumatoid arthritis, Holter electrocardiogram
Of 28 dogs, 21 (75%) showed electrocardiographic changes (Table 1) such as sinus tachycardia, sinus arrhythmia, atrial fibrillation, 2nd degree Mobitz type B heart block, right bundle branch block, atrial premature complex
, ST depression, ST elevation and complex changes as sinus arrest with LVC, sinus arrest with VPC, sinus arrest with ST elevation and LVC, VPC, broad QRS with tachycardia (Fig.
Dogs with ventricular premature complex and ventricular tachycardia were attended immediately with 2% Xylocaine given intravenously @ 2mg/kg as bolus over 2 minutes followed by a maintenance of 50|jg/kg/minutes in 5% Dextrose solution intravenously subject to a maximum of 8 mg in 6 hours.
Atrial arrhythmias included atrial flutter, atrial fibrillation, atrial tachycardia, atrial premature complex and AV junctional disturbances.
The ninth QRS is a ventricular premature complex
, and the next three complexes are sinus-initiated.
Alternate sinus P waves are fused with the terminal portion of each ventricular premature complex and reach the atrioventricular conduction system in its absolute refractory period.
Because the beginning of alternate P waves is buried in a ventricular premature complex, the P-P intervals are best measured from the end of one P wave to the end of the next P wave.
The refractory period of A-V bypass tracts often is long, which is the basis of the initiation of orthodromic A-V reciprocating tachycardia when an atrial premature complex
blocks in the bypass tract and is conducted down the A-V node.
After the ventricular premature complex
in the middle of the tracing, all of the P-R intervals are markedly prolonged, suggesting dual atrioventricular (A-V) nodal pathways.
The sixth P wave is an atrial premature complex
that is conducted to the ventricles with a long P-R interval and initiates atrioventricular (A-V) nodal reentrant tachycardia.