Baseline | Rapid Pacing Only1-a | Rapid Pacing + V1a Blockade1-b | Rapid Pacing + AT1Blockade1-c | Rapid Pacing + Dual Blockade1-d | |
---|---|---|---|---|---|
Hemodynamics | |||||
Ambient heart rate (beats/min) | 106 ± 4 | 158 ± 51-e | 154 ± 101-e | 127 ± 71-e 1-f 1-g | 134 ± 21-e 1-f |
Mean aortic pressure (mm Hg) | 94 ± 1 | 88 ± 31-e | 87 ± 31-e | 64 ± 41-e 1-f 1-g | 74 ± 31-e 1-f 1-g 1-h |
LV function | |||||
LV end-diastolic dimension (cm) | 3.3 ± 0.1 | 5.8 ± 0.21-e | 5.2 ± 0.21-e 1-f | 4.9 ± 0.11-e 1-f | 5.0 ± 0.21-e 1-f |
LV fractional shortening (%) | 42 ± 1 | 21 ± 21-e | 25 ± 31-e | 25 ± 21-e | 29 ± 31-e 1-f |
LV peak wall stress (g/cm2) | 135 ± 3 | 351 ± 191-e | 297 ± 161-e 1-f | 192 ± 111-e 1-f 1-g | 232 ± 151-e 1-f 1-g 1-h |
LV end-systolic stress (g/cm2) | 27 ± 1 | 126 ± 111-e | 102 ± 121-e 1-f | 64 ± 111-e 1-f 1-g | 77 ± 121-e 1-f 1-g |
Neurohormonal profiles | |||||
Plasma norepinephrine (pg/ml) | 220 ± 20 | 1130 ± 1301-e | 750 ± 1401-e 1-f | 290 ± 401-f 1-g | 460 ± 901-e 1-f 1-g |
Plasma endothelin (fmol/ml) | 2.4 ± 0.2 | 12.5 ± 1.91-e | 10.2 ± 2.41-e | 3.8 ± 0.71-f 1-g | 8.6 ± 1.31-e 1-f 1-h |
Plasma angiotensin II (pg/ml) | 27 ± 3 | 534 ± 1501-e | 95 ± 301-e 1-f | 365 ± 1581-e 1-g | 273 ± 321-e 1-f 1-g |
Plasma lysine-vasopressin (pg/ml) | 1.8 ± 0.9 | 18.9 ± 11.41-e | 7.6 ± 5.7 | 0.5 ± 0.11-f | 13.3 ± 4.01-e 1-h |
Plasma atrial natriuretic peptide (pg/ml) | 160 ± 13 | 509 ± 761-e | 440 ± 281-e | 293 ± 261-e 1-f 1-g | 381 ± 701-e 1-f |
Sample size (n) | 32 | 10 | 8 | 7 | 7 |
All values are presented as mean ± S.E.
↵1-a Rapid pacing only: 21 days of pacing; 240 beats/min.
↵1-b Rapid pacing + V1a blockade: rapid pacing with concomitant treatment with SR49059 (60 mg/kg b.i.d.).
↵1-c Rapid pacing + AT1 blockade: rapid pacing with concomitant treatment with irbesartan (30 mg/kg b.i.d.).
↵1-d Rapid pacing + dual blockade: rapid pacing only with concomitant treatment with irbesartan (30 mg/kg b.i.d.) and SR49059 (60 mg/kg b.i.d.).
↵1-e P < .05 versus baseline.
↵1-f P < .05 versus rapid pacing only.
↵1-g P < .05 versus rapid pacing + V1a blockade.
↵1-h P < .05 versus rapid pacing + AT1 blockade.