SHORT-TERM ATRIOVENTRICULAR SEQUENTIAL PACING DOES NOT ADVERSELY AFFECT COLLATERAL BLOOD-FLOW - A STUDY DURING ANGIOPLASTY

Altered sequence of ventricular activation sequence results in marked derangements in mechanical events. In the present study, we investigat ed the comparative effects of atrial and AV sequential pacing on colla teral blood flow during angioplasty. Twenty-eight patients with stable angina and left anterior descending artery disease undergoing balloon angioplasty were studied. Collateral flow was determined during ballo on inflation from the distal flow velocity of the ipsilateral artery ( 17 patients) or from the increase of the maximal diastolic blood flow velocity (Vc) of the contralateral artery (41 patients). Flow measurem ents tr ere made using the Doppler flow guidewire. The relative resist ance in the collateral vascular bed (RR) also was estimated in the lat ter group of patients. After the first balloon inflation, two similar consecutive balloon inflations rt ere done under atrial and AV sequent ial pacing, at a rate of 15 beats/min higher than the sinus rate, in t he absence of vasoactive medication. One minute after the initiation o f pacing, the second and third balloon inflations rr ere begun and the pacing continued until the balloon inflations were completed. In the ipsilateral group, average peak velocity was 84.6 +/- 24.2 mm/s during atrial pacing and 82.7 +/- 29.7 mm/s during AV sequential pacing (P = NS). In the contralateral group, Vc was 18% +/- 22% during atrial pac ing and 17% +/- 14% during AV sequential pacing, and the RR was 4.5 +/ - 4.7 and 4.9 +/- 6.4, respectively (both P = NS). The coronary wedge/ mean blood pressure tvas similar during the two tested balloon inflati ons. Short-term AV sequential pacing at rest does not adversely affect collateral blood flow and resistance in patients with left anterior d escending artery disease.