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Titolo: Heartrate variability effects of betaadrenoceptor agonists (xamoterol, prenalterol, and salbutamol) assessed nonlinearly with scatterplots and sequence methods
Autore: Silke, B; Hanratty, CG; Riddell, JG;
 Indirizzi:
 Queens Univ Belfast, Whitla Div Med, Belfast BT9 7BL, Antrim, North Ireland Queens Univ Belfast Belfast Antrim North Ireland BT9 7BL m, North Ireland
 Titolo Testata:
 JOURNAL OF CARDIOVASCULAR PHARMACOLOGY
fascicolo: 6,
volume: 33,
anno: 1999,
pagine: 859  867
 SICI:
 01602446(199906)33:6<859:HVEOBA>2.0.ZU;2T
 Fonte:
 ISI
 Lingua:
 ENG
 Soggetto:
 ACUTE MYOCARDIALINFARCTION; TIMEDOMAIN MEASURES; RR INTERVALS; CORONARYARTERY DISEASE; VENTRICULAR ARRHYTHMIAS; PERIOD VARIABILITY; FREQUENCY DOMAINS; SPECTRALANALYSIS; PROGNOSTIC VALUE; METOPROLOL;
 Keywords:
 heartrate variability; scatterplot; nonlinear; betaadrenoceptor; partial agonist;
 Tipo documento:
 Article
 Natura:
 Periodico
 Settore Disciplinare:
 Clinical Medicine
 Life Sciences
 Citazioni:
 55
 Recensione:
 Indirizzi per estratti:
 Indirizzo: Silke, B Queens Univ Belfast, Whitla Div Med, Whitla Med Bldg,97 Lisburn Rd, Belfast Queens Univ Belfast Whitla Med Bldg,97 Lisburn Rd Belfast AntrimNorth Ireland BT9 7BL



 Citazione:
 B. Silke et al., "Heartrate variability effects of betaadrenoceptor agonists (xamoterol, prenalterol, and salbutamol) assessed nonlinearly with scatterplots and sequence methods", J CARDIO PH, 33(6), 1999, pp. 859867
Abstract
Full antagonists of the cardiac betaadrenoceptor improve heartrate variability (HRV) in humans; however, partial agonism at the beta(2)adrenoceptor has been suggested to decrease HRV. We therefore studied the HRV effects of some partial agonists of the beta(1) and beta(2)adrenoceptors in normal volunteers. Under doubleblind and randomised conditions (Latin square design), eight healthy volunteers received placebo; xamoterol, 200 mg (beta(1)adrenoceptor partial agonist); prenalterol, 50 mg (beta(1) and beta(2)adrenoceptor partial agonist); salbutamol, 8 mg (beta(2)adrenoceptor partial agonist); ICI 118,551, 25 mg (selective beta(2)adrenoceptor antagonist);and combinations of each partial agonist with ICI 118,551. Single oral doses of medication (at weekly intervals) were administered at 22:30 h with HRV assessed from the overnight sleeping heart rates. HRV was determined by using standard timedomain summary statistics and two nonlinear methods, thePoincare plot (scatterplot) and cardiac sequence analysis. On placebo, thesleeping heart rate decreased significantly, between 2 and 8 h after dosing. The heart rate with ICI 118,551 was unaltered. Xamoterol, prenalterol, and salbutamol increased the sleeping heart rate. ICI 118,551 blocked the heartrate effects of salbutamol, attenuated those of prenalterol, but did not influence the xamoterol heart rate. The scatterplot (Poincare) area was reduced by beta(1)adrenoceptor (xamoterol), beta(2)adrenoceptor (salbutamol), and combined beta(1) and beta(2)adrenoceptor (prenalterol) agonism. Areduction in scatterplot length followed salbutamol, prenalterol alone, and prenalterol in combination with ICI 118,551. The geometric analysis of the scatterplots allowed width assessment (i.e., dispersion) at fixed RR intervals. At higher heart rates (i.e., 25 and 50% of RR scatterplot length), dispersion was decreased after xamoterol, prenalterol, and prenalterol/ICI 118,551. Cardiac sequence analysis (differences between three adjacent beats; Delta RR vs. Delta RRn+1) assessed the shortterm pat terns of cardiac acceleration and deceleration; four patterns were identified: +/+ (a lengthening sequencing), +/ or /+ (balanced sequences), and finally / (a shortening sequence). Cardiac acceleration or deceleration episodes (i.e., numberof times Delta RR and Delta RRn+1 were altered in the same direction) wereincreased after salbutamol and prenalterol. In conclusion, partial agonismat either the cardiac beta(1)adrenoceptor (xamoterol), beta(2)adrenoceptor (salbutamol), and beta(1) plus beta(2) adrenoceptors (prenalterol) altered the autonomic balance toward sympathetic dominance in healthy volunteers; blockade of the beta(2)adrenoceptor with the highly selective beta(2)antagonist ICI 118,551 prevented the effects of salbutamol on HRV, attenuated the HRV effects of prenalterol, but had no effect on the actions of xamoterol. Agonism at both the beta(1) and beta(2)adrenoceptor reduced HRV inhealthy subjects; the implications for the preventive use of the betaadrenoceptor compounds in cardiovascular disease warrant further investigation.
ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 02/10/20 alle ore 01:57:59