Difference in mechanical atrioventricular delay between atrial sensing and atrial pacing modes in patients with hypertrophic and dilated cardiomyopathy: An electrical hemodynamic catheterization study

For optimal pacemaker programming in patients with cardiomyopathy, it is important to understand the relationship between the programmed right atrial and ventricular delay and the mechanical contraction delay of the left atrium and left ventricle. Methods: We analyzed data from 34 patients with dilated cardiomyopathy (14) or hypertrophic obstructive cardiomyopathy (20) who had dual-chamber P-synchronous pacing (VDD) and atrioventricular sequential pacing (DVI) during hemodynamic catheterization. Using multiple atrioventricular intervals during VDD and DVI pacing, the relationship of the programmed right atrial-right ventricular interval to the mechanical left atrial-left ventricular delay (assessed by high-fidelity pressures) was determined. Results: We found that the optimal mechanical left atrial-left ventricular delay was 120 ms, which required a programmed right atrial-right ventricular interval of 160 ms during DVI pacing. Also, the mean difference in right atrial-right ventricular pacing interval between VDD and DVI modes was 54+/-28 ms (range, 10-120 ms) in the hypertrophic obstructive cardiomyopathy group and 64+/-38 ms (range, 20-150 ms) in the dilated cardiomyopathy group. Conclusions: We concluded that the optimal right atrial-right ventricular interval during DVI pacing was 160 ms and that, to achieve the same mechanical left atrial-left ventricular delay, the programmed right atrial-right ventricular interval during VDD pacing was approximately 50 ms to 60 ms shorter than during DVI pacing. However, the difference of electrical atrioventricular pacing interval in VDD and DVI may vary widely from patient to patient.