Altered sympathetic tone in hypertensives with angina and lowered threshold for pacing ischemia.
To determine the role of the sympathetic nervous system in myocardial ischemia with essential hypertension, plasma norepinephrine, heart rate (HR), blood pressure (BP), and the HR.BP double product at the time of silent ischemia during pacing and exercise treadmill test (ETT) were compared with basal values in 20 patients with sustained essential hypertension and stable angina, 3 to 60 days (12.6 +/- 11.6) after discontinuation of all antihypertensive and coronary vasodilator therapy. Group I (N = 6) had silent ischemia with a higher HR.BP product at ETT than at pacing (ratio = 157 +/- 10.4% [+/- SD] v a value in group II [N = 5] of 102 +/- 18.8 [P less than .01]. Group III (N = 9) had no silent ischemia at ETT or pacing. Group I v group II plasma norepinephrine levels at rest and with pacing silent ischemia were 76 +/- 37 v 138 +/- 36 pg/mL, P less than .02, and 101 +/- 50 v 230 +/- 43 pg/mL, P less than .01, respectively. In groups I and II plasma norepinephrine levels were significantly lower than those of group III. Eleven of 20 patients had ischemia on pacing or ETT. Left ventricular myocardial mass were greater (224 +/- 49 v 180 +/- 28 g, p less than .05), HR (67 +/- 13 v 76 +/- 11 beats/min, P = NS) and plasma norepinephrine levels at rest (104 +/- 47 v 241 +/- 99 pg/mL, P less than .01), pacing (160 +/- 81 v 338 +/- 94 pg/mL, P less than .01), and ETT (758 +/- 268 v 1203 +/- 611 pg/mL, P less than .05), were lower in patients with ischemia (N = 11, group II) than in patients without ischemia (N = 9, group III) on pacing or ETT. Eight patients were on reserpine prestudy; reserpine prestudy was associated with lower basal HR (63 +/- 9 v 76 +/- 12 beats/min, P less than .05) and plasma norepinephrine (106 +/- 48 v 169 +/- pg/mL, P less than .07) and greater ratio of HR.BP double product on ETT/pacing, (141 +/- 33 v 111 +/- 19, P less than .02). The sympathetic nervous tone of group I was low at baseline but there may have been raised alpha/beta-receptor responsiveness to laboratory stresses with concomitant micro/macrovascular constriction at higher oxygen demand.(ABSTRACT TRUNCATED AT 400 WORDS)
Oishi
S
S
Department of Medicine, University of Southern California, Los Angeles.
Yurenev
A
A
Parfyonova
E
E
Lee
D D
DD
Dubov
P
P
Nikulin
I
I
Kosenko
A
A
Konyaeva
E
E
Balyakina
E
E
Atakhanov
S
S
D000328:Adult; D000787:Angina Pectoris / Q000150:complications* / Q000188:drug therapy / Q000503:physiopathology*; D001794:Blood Pressure / Q000502:physiology; D003327:Coronary Disease / Q000150:complications* / Q000503:physiopathology*; D004837:Epinephrine / Q000097:blood; D005080:Exercise Test; D006339:Heart Rate / Q000502:physiology; D006439:Hemodynamics; D006801:Humans; D006973:Hypertension / Q000150:complications* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D012110:Reserpine / Q000627:therapeutic use; D013564:Sympathetic Nervous System / Q000502:physiology*
D012110:Reserpine; D009638:Norepinephrine; D004837:Epinephrine