title: Importance of chronotropic response and left ventricular long-axis function for exercise performance in patients with heart failure and preserved ejection fraction.
abstract: BACKGROUND
  We evaluated the relationship between the degree of chronotropic incompetence and left ventricular (LV) impairment during exercise with severity of exercise intolerance in patients with heart failure and preserved ejection fraction (HFPEF).
  
  
  METHODS
  All patients underwent exercise echocardiography during bicycle Ergometer exercise with the acquisition of long-axis tissue Doppler imaging (TDI). Peak heart rates during exercise were also recorded and the percentages of maximal age-predicted heart rate (%MPHR) and heart rate reserve (%HRR) were calculated thereby. Besides, cardiopulmonary exercise testing was performed with peak oxygen consumption (VO2) measuring averaged at the highest 30-second during exercise.
  
  
  RESULTS
  Forty HFPEF patients (aged 65±9 years; 75% male) were divided into two groups according to the median of peak VO2: patients with peak VO2<16.5 and ≥16.5 ml/kg/min, respectively. Patients with lower peak VO2 had decreased peak heart rates, %MPHR, %HRR, stroke volume and cardiac indices (LVSI and LVCI) than those with higher peak VO2 (all p<0.05). The LV long-axis functions (TDI Sm, Em, s' and e') were reduced in patients with lower peak VO2 (all p<0.05). Moreover, peak VO2 correlated with the following parameters: peak heart rates, %MPHR, %HRR, LVSI, LVCI, TDI Sm, Em, s' and e'(all p<0.05).
  
  
  CONCLUSIONS
  The degree of blunted chronotropic response and impaired LV long-axis function were more profound in HFPEF patients with poor exercise performance.
authors.affiliation: Institute of Vascular Medicine, Li Ka Shing Institute of Health Science, S.H. Ho Cardiovascular Disease and Stroke Centre, Hong Kong; Division of Cardiology, Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong; Department of Ultrasound, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.affiliation: Institute of Vascular Medicine, Li Ka Shing Institute of Health Science, S.H. Ho Cardiovascular Disease and Stroke Centre, Hong Kong; Division of Cardiology, Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Fang
authors.initials: F
authors.lastname: Fang
authors.affiliation: Cardiac Medicine Unit, Grantham Hospital, Hong Kong.
authors.forename: Gabriel Wai-Kwok
authors.initials: GW
authors.lastname: Yip
authors.affiliation: Institute of Vascular Medicine, Li Ka Shing Institute of Health Science, S.H. Ho Cardiovascular Disease and Stroke Centre, Hong Kong; Division of Cardiology, Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong.
authors.forename: John E
authors.initials: JE
authors.lastname: Sanderson
authors.affiliation: Institute of Vascular Medicine, Li Ka Shing Institute of Health Science, S.H. Ho Cardiovascular Disease and Stroke Centre, Hong Kong; Division of Cardiology, Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Wei
authors.initials: W
authors.lastname: Feng
authors.affiliation: Institute of Vascular Medicine, Li Ka Shing Institute of Health Science, S.H. Ho Cardiovascular Disease and Stroke Centre, Hong Kong; Division of Cardiology, Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Jun-Min
authors.initials: JM
authors.lastname: Xie
authors.affiliation: Institute of Vascular Medicine, Li Ka Shing Institute of Health Science, S.H. Ho Cardiovascular Disease and Stroke Centre, Hong Kong; Division of Cardiology, Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Xiu-Xia
authors.initials: XX
authors.lastname: Luo
authors.affiliation: Institute of Vascular Medicine, Li Ka Shing Institute of Health Science, S.H. Ho Cardiovascular Disease and Stroke Centre, Hong Kong; Division of Cardiology, Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Alex Pui-Wai
authors.initials: AP
authors.lastname: Lee
authors.affiliation: Institute of Vascular Medicine, Li Ka Shing Institute of Health Science, S.H. Ho Cardiovascular Disease and Stroke Centre, Hong Kong; Division of Cardiology, Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong. Electronic address: yylam@me.com.
authors.forename: Yat-Yin
authors.initials: YY
authors.lastname: Lam
mesh_terms: D000368:Aged; D025401:Echocardiography, Stress; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D013318:Stroke Volume / Q000502:physiology*; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000503:physiopathology*
keywords: Chronotropic response; HFPEF; Left ventricular long-axis function; Stress echocardiography