Background— We tested the hypothesis that intracoronary delivery of an adenovirus encoding adenylyl cyclase type VI (Ad.AC_VI) would be associated with increased left ventricular (LV) function in pigs with congestive heart failure.

Methods and Results— Pigs (52±6 kg; n=16) underwent placement of pacemakers, LV pressure transducers, and left atrial and aortic catheters. Physiological and echocardiographic studies were obtained from conscious animals 13 days later, and pacing was initiated (220 bpm). Seven days later, measures of LV function were reduced, documenting severe LV dysfunction and dilation. Pigs then received intracoronary Ad.AC_VI (1.4×10¹² vp; n=7) or saline (PBS; n=9) (randomized, blinded), with concomitant infusion of nitroprusside (50 μg/min, 6.4 minutes) to increase gene transfer. Pacing was continued for 14 days, and final studies were obtained. The a priori key end point was change in LV dP/dt during isoproterenol infusion (pre-Ad.AC_VI value minus value after 21 days of pacing). Pigs receiving Ad.AC_VI showed a smaller decrease in both LV +dP/dt (P=0.0014) and LV −dP/dt (P=0.0008). Serial echocardiography showed that Ad.AC_VI treatment was associated with increased LV function and reduced LV dilation and that end-systolic wall stress was reduced. AC-stimulated cAMP production was increased 1.7-fold in LV samples from Ad.AC_VI-treated pigs (P=0.006), and B-type natriuretic peptide was reduced (0.035). Gene transfer was confirmed by polymerase chain reaction.

Conclusions— AC_VI gene transfer increases LV function and attenuates deleterious LV remodeling in congestive heart failure.