title: Clinical and haemodynamic correlates of heart rate turbulence as a non-invasive index of baroreflex sensitivity in chronic heart failure.
abstract: HRT (heart rate turbulence), describing the heart rate changes following a premature ventricular contraction, has been regarded as an indirect index of baroreflex function. However, limited data are available on its relationship with invasive assessment by phenylephrine injection (Phe-slope). In the present study, we therefore compared these methodologies in a series of patients with HF (heart failure) in which both measures together with clinical and haemodynamic data were available. HRT parameters [TO (turbulence onset) and TS (turbulence slope)] were measured from 24-h Holter recordings obtained within 1 week of baroreflex sensitivity assessment and right heart haemodynamic evaluation (Swan-Ganz catheter). HRT was computable in 135 out of 157 (86%) patients who had both a phenylephrine test and haemodynamic evaluation. TO and TS significantly correlated with Phe-slope (r=-0.39, P<0.0001 and r=0.66, P<0.0001 respectively). Age, baseline heart rate, LVEF (left ventricular ejection fraction), PCP (pulmonary capillary pressure), CI (cardiac index) and sodium were significant and independent predictors of Phe-slope, accounting for 51% of its variability. Similarly, age, baseline heart rate and PCP, and NYHA (New York Heart Association) classes III-IV were independent predictors for TS and explained 48% of its variability, whereas only CI and LVEF were found to be significantly related to TO and explained a very limited proportion (20%) of the variability. In conclusion, these results suggest that HRT may be regarded as a surrogate measure of baroreflex sensitivity in clinical and prognostic evaluation in patients with HF.
authors.affiliation: Department of Cardiology, S. Maugeri Foundation, Scientific Institute of Montescano, IRCCS, Montescano, Pavia, Italy. mariateresa.larovere@fsm.it
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: La Rovere
authors.forename: Roberto
authors.initials: R
authors.lastname: Maestri
authors.forename: Gian Domenico
authors.initials: GD
authors.lastname: Pinna
authors.forename: Peter
authors.initials: P
authors.lastname: Sleight
authors.forename: Oreste
authors.initials: O
authors.lastname: Febo
mesh_terms: D017704:Baroreflex / Q000502:physiology*; D002302:Cardiac Output / Q000502:physiology; D002316:Cardiotonic Agents; D015716:Electrocardiography, Ambulatory / Q000379:methods; D005260:Female; D006333:Heart Failure / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010656:Phenylephrine; D011379:Prognosis; D011669:Pulmonary Wedge Pressure / Q000502:physiology; D012189:Retrospective Studies; D013318:Stroke Volume / Q000502:physiology; D018879:Ventricular Premature Complexes / Q000503:physiopathology*
chemical_list: D002316:Cardiotonic Agents; D010656:Phenylephrine