Atrioventricular dissociation detected by suprasternal M-mode echocardiography: a clue to the diagnosis of ventricular tachycardia.
Twenty-two patients were studied by suprasternal M-mode echocardiography during ventricular tachycardia (VT). Adequate echocardiograms were obtained from 19 patients. Thirteen patients showed atrioventricular (AV) dissociation and 6 patients a ventriculoatrial contraction pattern according to the left atrial (LA) contraction obtained from the suprasternal notch. In 1 of these 6 patients, a 2:1 block retrograde was found by echocardiography. In another patient, an intermittent block occurred in the retrograde direction. In 4 patients, a constant relation between the QRS complex and LA contraction soon after the beginning of the QRS complex was seen, demonstrating a 1:1 ventriculoatrial conduction. According to the LA contraction obtained from the suprasternal echocardiogram, 13 patients showed AV dissociation and 6 patients a retrograde conduction to the LA. From the analysis of the 12-lead standard electrocardiogram obtained simultaneously during VT, AV dissociation could be recognized in only 3 patients. Thus, AV dissociation during VT is more easily diagnosed with suprasternal M-mode echocardiography than with the standard electrocardiogram.
D000328:Adult; D000368:Aged; D001283:Atrioventricular Node / Q000503:physiopathology*; D004452:Echocardiography; D004562:Electrocardiography; D005260:Female; D006325:Heart Atria / Q000503:physiopathology; D006329:Heart Conduction System / Q000503:physiopathology*; D006352:Heart Ventricles; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D013610:Tachycardia / Q000175:diagnosis* / Q000503:physiopathology