INTRODUCTION: We hypothesized that autonomic activity preceding spontaneous sustained monomorphic @entity1165 (VTsm) as assessed by heart rate (HR) and RR interval variability ( @entity27320 ) differs between type 1 VTsm which is initiated by morphologically distinct, early cycle, possibly triggering @entity1540 ( @entity1540 ) and type 2 VTsm in which the initial complex has a QRS waveform identical to subsequent complexes. METHODS AND RESULTS: Baseline Holter tapes (1,646) from a clinical trial were scanned for VTsm. QRS complexes of VTsm were compared by two-lead cross-correlation to distinguish type 1 and type 2 VTsm. Frequency domain @entity27320 index were estimated over 5 minutes, 15 minutes, and 24 hours. Type 1 and type 2 VTsm were present in 15 (group 1) and 33 (group 2) of 48 @entity1 , respectively. HR did not change in group 1 (88.4+/-15.2 to 89.7+/-13.0 beats/min, P = 0.89), but increased before the onset of VTsm in group 2 (74.3+/-16.3 to 81.2+/-18.0 beats/min, P < 0.001). @entity27320 index were severely depressed in both groups. No @entity27320 index changed significantly before the onset of type 1 VTsm, whereas significant changes occurred before type 2 VTsm from 24-hour average to 30 minutes before VTsm in very low (very low-frequency power [VLFP]: 6.62+/-1.53 to 6.20+/-2.07 ln msec2, P = 0.036), low (low-frequency power [LFP]: 5.61+/-1.43 to 5.28+/-1.59 ln msec2, P = 0.004), normalized low (normalized low-frequency power [LFPn]: -0.48+/-0.58 to -0.55+/-0.64 normalized units [nu], P = 0.05) and the ratio of LFP to high-frequency power (HFP) (LFP/HFP: 4.20+/-3.47 to 3.45+/-2.53, P = 0.017). Declines in @entity27320 index between 2 hours to the 30-minute period before VTsm occurred in group 2 but not group 1 in LFP (5.85 +/- 1.42 to 5.28 +/- 1.59 In msec, P = 0.043) and HFP (4.94 +/- 5.14 to 3.46 +/- 2.52 In msec2, P = 0.008), with a downward trend in LFP/HFP (4.94+/-5.14 to 3.45+/-2.53, P = 0.127) and LFPn (-0.38+/-0.36 to -0.55+/-0.64, P = 0.15), while HFPn tended to rise (-1.47+/-0.65 to -1.27+/-0.64, P = 0.15). CONCLUSIONS: HR and @entity27320 did not change before type 1 VTsm, suggesting that short-term changes in autonomic activity were not essential to initiation of apparent @entity2634 -triggered VTsm. In contrast, RR interval dynamics before type 2 VTsm suggested that short-term changes in neurohormonal activity contributed to @entity943 initiation. Heterogeneities in @entity943 onset may reflect distinct triggers and substrate properties that could provide a basis for effective therapeutic targets.

Distinctive RR dynamics preceding two modes of onset of spontaneous sustained XXXX . (ESVEM) Investigators. Electrophysiologic Study Versus Electrocardiographic Monitoring.

@entity1 :: ('9606', 'Species') :: ['patients'] @entity1165 :: ('MESH:D017180', 'Disease') :: ['ventricular tachycardia'] @entity2634 :: ('MESH:D011143', 'Chemical') :: ['PVC'] @entity27320 :: ('154334', 'Species') :: ['RRV'] @entity1540 :: ('MESH:D018879', 'Disease') :: ['premature ventricular complexes', 'PVCs'] @entity943 :: ('MESH:D001145', 'Disease') :: ['arrhythmia']
@entity1165 :: (MESH:D017180,Disease) :: ['ventricular tachycardia']
