1. Dual-Chamber Pacing for Cardiomyopathies: A 1996 Clinical Perspective
Rick A. Nishimura, M.D., John D. Symanski, M.D., David G. Hurrell, M.D., Jane M. Trusty, R.N., David L. Hayes, M.D., A. Jamil Tajik, M.D. 
Mayo Clinic Proceedings 
Volume 71, Issue 11, Pages (November 1996)
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Copyright © 1996 Mayo Foundation for Medical Education and Research Terms and Conditions

2. Fig. 1
Normal sinus rhythm (Left) and improvement in hemodynamics during dual-chamber pacing (Right) in patient with hypertrophie obstructive cardiomyopathy. High-fidelity left ventricular (LV) pressure curve with simultaneous pressure curve in ascending aorta (Ao) is shown with simultaneous continuous wave Doppler study of left ventricular outflow tract. (From Symanski and Nishimura.2 By permission.)
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3. Fig. 2
High-fidelity left atrial (LA) and left ventricular (LV) pressures in patient during atrial pacing with native antegrade conduction (Left) and atrioventricular pacing with short atrioventricular delay of 60 ms (Right). During atrioventricular pacing, mean left atrial pressure increased from 25 mm Hg (Left) to 34 mm Hg (Right).
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4. Fig. 3
High-fidelity pressure curve of left ventricle (LV), left atrium (LA), and ascending aorta (Ao) demonstrating changes in left ventricular outflow gradient and left atrial pressure that occur during dual-chamber atrial pacing (A-Pace) at various atrioventricular (A-V) intervals in patient with hypertrophie obstructive cardiomyopathy (see text for further details). (From Symanski and Nishimura.2 By permission.)
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5. Fig. 4
Substantial changes in hemodynamics resulting from various sites of right ventricular pacing wire in patient with hypertrophie cardiomyopathy. Left, Ventricular pacing wire is placed in midseptal region near right ventricular outflow tract. High-fidelity pressures in left ventricle (LV), left atrium (LA), and ascending aorta (Ao) are shown. During P-synchronous pacing with atrioventricular delay of 60 ms (P-60), left ventricular outflow tract gradient is 90 mm Hg with a large “V” wave. Left ventricular outflow tract gradient and “V” wave on left atrial pressure curve both decrease as pacemaker is changed to normal sinus rhythm (NSR). Right, In same patient, ventricular pacing wire is placed in right ventricular apex under echocardiographic guidance. Note minimal change in both left ventricular outflow tract gradient and left atrial pressure during P-synchronous pacing with atrioventricular delay of 60 ms (P-60) versus NSR.
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6. Fig. 5
Detrimental effects of P-synchronous pacing in patient with hypertrophie obstructive cardiomyopathy. High-fidelity pressures in left ventricle (LV), left atrium (LA), and aorta (Ad) are shown during P-synchronous (P-Synch) pacing at 60 ms, 80 ms, 100 ms with fusion, and during normal sinus rhythm. Optimal hemodynamics occur when patient is in normal sinus rhythm. (From Symanski and Nishimura.2 By permission.)
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7. Fig. 6
Patient with dilated cardiomyopathy in whom dual-chamber pacing at short atrioventricular interval was associated with no change or even slight deterioration in hemodynamics. High-fidelity pressure curves in left ventricle (LV), pulmonary capillary wedge pressure (PCWP), and simultaneous mitral flow velocity curves are shown. Left, During normal sinus rhythm (NSR), cardiac outflow (CO) is 6.11/min, and peak positive rate of change in left ventricular pressure (Dp/dt) is 860 mm Hg/s. Right, During P-synchronous pacing with atrioventricular delay of 60 ms (P-SYNCH 60), there is now separation of early and late diastolic filling velocities on mitral flow velocity curve; however, this is accompanied by decrease in CO and peak positive Dp/dt and increase in PCWP. (From Nishimura and associates.47 By permission.)
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8. Fig. 7
Simultaneous recordings of high-fidelity pressures in left ventricle (LV) and left atrium (LA) with simultaneous continuous Doppler flow velocity curves of mitral régurgitation (top) and pulsed wave Doppler study of mitral inflow velocities (bottom) illustrating improvement in hemodynamics during dual-chamber pacing in patient with dilated cardiomyopathy. Left, During normal sinus rhythm (NSR), there is presystolic mitral régurgitation (arrows, upper left panel) on continuous wave Doppler recordings as left atrial pressure decreases lower than left ventricular pressure before onset of ventricular systole. Note early cessation of transmitral flow as shown on mitral inflow velocity curve (bottom). Right, During P-synchronous pacing with atrioventricular delay of 140 ms (P-Synch 140), diastolic mitral régurgitation disappears on mitral flow velocity curve (top), and transmitral flow continues throughout diastole (bottom). In comparison with NSR, left ventricular systolic pressure increases, and left atrial pressure decreases, factors reflected in higher peak velocity of mitral régurgitation continuous wave signal. Cardiac output has been increased by 40% during dual-chamber pacing in this patient, despite no change in heart rate. (Modified from Symanski and Nishimura.2 By permission.)
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9. Fig. 8
Continuous wave mitral régurgitation signal and high-fidelity left ventricular and left atrial pressure tracings in patient with dilated cardiomyopathy and deterioration of hemodynamics with dual-chamber pacing, despite first-degree atrioventricular block on resting electrocardiogram. Left, During normal sinus rhythm, timing of atrial and ventricular synchrony is appropriate. Right, During P-synchronous pacing with atrioventricular delay of 60 ms, left ventricular systolic pressure decreases, left atrial pressure increases, and continuous wave mitral régurgitation peak velocity decreases. (From Symanski and Nishimura.2 By permission.)
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10. Fig. 9
High-fidelity left atrial (LA) and left ventricular pressures in patient with dilated cardiomyopathy. Left, Atrioventricular (AV) interval is too short with increase of mean left atrial pressure to 42 mm Hg. Center, AV interval is optimal with increase in cardiac output to 5.2 L/min. Right, AV interval is too long with decrease in cardiac output to 3 L/min. dp/dt = rate of change in left ventricular pressure.
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