BACKGROUND: An acute increase in blood pressure is associated with the occurrence of @entity1540 ( @entity1540 ). OBJECTIVE: We aimed to study the timing of these @entity1540 with respect to afterload-induced changes in @entity296 in a controlled, preclinically relevant, novel closed-chest @entity1707 model. METHODS: An acute left ventricular (LV) afterload challenge was induced by @entity661 in the descending aorta, lasting 5-10 heartbeats (8 @entity1707 ; 396 inflations). RESULTS: Balloon inflation enhanced the reflected wave (augmentation index 30%    8% vs 59%    6%; P < .001), increasing systolic central blood pressure by 35%    4%. This challenge resulted in a more abrupt LV pressure decline, which was delayed beyond ventricular repolarization (rate of pressure decline 0.16    0.01 mm Hg/s vs 0.27    0.04 mm Hg/ms; P < .001 and interval T-wave to peak pressure 1    12 ms vs 36    9 ms; P = .008), during which the velocity of myocardial shortening at the basal septum increased abruptly (ie, postsystolic shortening) (peak strain rate -0.6    0.5 s(-1) vs -2.5    0.8 s(-1); P < .001). It is exactly at this time of LV pressure decline, with increased postsystolic shortening, and not at peak pressure, that @entity1540 occur (22% of inflations). These @entity1540 preferentially occurred at the basal and apical segments. In the same regions, monophasic action potentials demonstrated the appearance of delayed afterdepolarization-like transient depolarizations as origin of @entity1540 . CONCLUSION: An acute blood pressure increase results in a more abrupt LV pressure decline, which is delayed after ventricular repolarization. This has a profound effect on myocardial mechanics with enhanced postsystolic shortening. Coincidence with induced transient depolarizations and @entity1540 provides support for the mechanoelectrical origin of pressure-induced @entity16257 .

Further insights into blood pressure induced @entity16257 : Transient depolarizations are associated with fast XXXX upon pressure decline.

@entity1707 :: ('9823', 'Species') :: ['pigs', 'pig'] @entity296 :: ('MESH:D009202', 'Disease') :: ['myocardial deformation'] @entity16257 :: ('MESH:D005117', 'Disease') :: ['premature beats'] @entity661 :: ('MESH:D054549', 'Disease') :: ['partial balloon inflation'] @entity1540 :: ('MESH:D018879', 'Disease') :: ['premature ventricular complexes', 'PVCs']
@entity296 :: (MESH:D009202,Disease) :: ['myocardial deformation']
