Influence of left ventricular dysfunction on the role of atrial contraction
An echocardiographic-hemodynamic study in dogs
Brian D. Hoit, BS, FACC* and
Marjorie Gabel, BS
* Department of Medicine, Case Western Reserve University, University Hospitals of Cleveland, 11100 Euclid Avenue, Cleveland, Ohio, USA
Department of Medicine, University of Cincinnati, Box 670542, Cincinnati, Ohio 45267, USA
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Figure 1 Electrocardiograms before (left) and after (right) radiofrequency (RF) AV nodal ablation. Recordings from top to bottom are from the surface electrocardiogram (ECG), the distal electrode (A-V), and from the electrode across the bundle of His. The His bundle potentials are circled. Atrial and ventricular potentials correspond to the electrocardiographic P and QRS waves. Note the production of complete heart block on the right.
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Figure 2 Mitral flow in a representative animal at baseline (top left panel), and after one week of rapid atrial pacing at 400 beats/min (bottom left panel), two weeks of rapid ventricular pacing at 220 beats/min (top right panel), and both rapid atrial and ventricular pacing (bottom right panel). Recordings were obtained during atrioventricular sequential pacing at 80 beats/min. The "E" and "A" waves correspond to early ventricular diastole and left atrial systole, respectively. Doppler scale = 20 cm/s. See text for details.
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Figure 3 Left atrial appendage flow in the representative animal shown in Figure 2 at baseline (top left panel), and after one week of rapid atrial pacing at 400 beats/min (bottom left panel), two weeks of rapid ventricular pacing at 220 beats/min (top right panel), and both rapid atrial and ventricular pacing (bottom right panel). Recordings were obtained during atrioventricular sequential pacing at 80 beats/min. The "e" and "a" waves correspond to early ventricular diastole and left atrial systole, respectively. Doppler scale = 20 cm/s. See text for details.
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Figure 4 Pulmonary vein flow from the animal in Figures 2 and 3, again at baseline (top left panel), and after one week of rapid atrial pacing at 400 beats/min (bottom left panel), two weeks of rapid ventricular pacing at 220 beats/min (top right panel), and both rapid atrial and ventricular pacing (bottom right panel). Recordings were obtained during atrioventricular sequential pacing at 80 beats/min. J1 = early systolic flow; J2 = late systolic flow; K = diastolic flow. A prominent atrial reversal wave (A) is seen after rapid ventricular pacing. Doppler scale = 20 cm/s. Diastolic reversals in the lower two panels occur during isovolumic ventricular systole and are not pulmonary vein A velocities. See text for details.
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