Doppler tissue imaging in the assessment of atrioventricular conduction time: validation of a novel technique and comparison with electrophysiologic and pulsed wave Doppler-derived equivalents in an animal model.
Accurate assessment of atrioventricular conduction time (AVCT) is crucial for early detection of evolving fetal heart block. Simultaneous pulsed wave Doppler (PD) interrogation of left ventricular inflow and outflow is mainly used to study fetal AVCT. Limitations of this modality include its dependency on loading conditions and merging early and late diastolic inflow waves at faster heart rate (HR). Sequential analysis of atrioventricular myocardial motion by Doppler tissue imaging (DTI) might be more useful in this regard. In 15 open-chest pigs, AVCT was measured by PD, DTI, and electrocardiogram at baseline HR and during incremental atrial pacing up to 200 beats/min. Electromechanical delay and pre-ejection period were assessed at baseline and maximal HR. DTI-derived AVCT correlated better with PR intervals and allowed measurements at faster HRs than did PD (P < .05). Pre-ejection period prolonged with faster HR (P < .001), unlike electromechanical delay. In conclusion, DTI allows more accurate measurement of AVCT over a wider HR range than does PD.
Nii
Masaki
M
Division of Cardiology, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
Shimizu
Mikiko
M
Roman
Kevin S
KS
Konstantinov
Igor
I
Li
Jia
J
Redington
Andrew N
AN
Jaeggi
Edgar T
ET
D000818:Animals; D001283:Atrioventricular Node / Q000000981:diagnostic imaging* / Q000502:physiology*; D015150:Echocardiography, Doppler / Q000379:methods*; D004562:Electrocardiography / Q000379:methods; D006329:Heart Conduction System / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology*; D006352:Heart Ventricles / Q000000981:diagnostic imaging; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D023421:Models, Animal; D009431:Neural Conduction / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013552:Swine; D016276:Ventricular Function; D016277:Ventricular Function, Left / Q000502:physiology