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Excessive breathlessness in patients with diastolic heart failure
  1. K K A Witte,
  2. N P Nikitin,
  3. J G F Cleland,
  4. A L Clark
  1. Department of Academic Cardiology, Castle Hill Hospital, Kingston upon Hull, UK
  1. Correspondence to:
    Dr Klaus Witte
    Academic Cardiology, Castle Hill Hospital, Castle Road, Cottingham, Hull HU16 5JQ, UK; klauswitte{at}hotmail.com

Abstract

Objectives: To establish the prevalence of preserved left ventricular (LV) systolic function (PSF) in 435 consecutive symptomatic patients referred to a heart failure clinic and to examine their ventilatory response to exercise when compared with 134 control volunteers.

Methods: 216 (50%) patients had systolic heart failure (SHF) (ejection fraction < 45%). 51 (11%) had an immediately apparent alternative causes of breathlessness and 168 (39%), with no obvious other cause of breathlessness, were divided into those with PSF and diastolic dysfunction (DD) (PSFDD; n  =  113 or 26% of referrals) and those without DD (PSFN; n  =  55 or 13% of referrals). The controls were divided into those with (CDD; n  =  32) and those without (CN; n  =  102) echocardiographic evidence of DD.

Results: Patients with SHF had lower peak oxygen consumption (pV̇o2), steeper slope of minute ventilation (V̇e) to carbon dioxide production, lower exercise time and shorter 6 min walk test than PSF patients and controls. PSFDD patients had lower pV̇o2, exercise time and 6 min walk test than CDD, although their echocardiograms were not different. Exercise capacity did not differ between PSFDD and PSFN patients. The slope relating V̇e to symptoms (Borg/V̇e slope) was less steep in those with SHF than in PSFDD (0.17 (0.04) v 0.20 (0.08), p < 0.05) and in PSFN (0.19 (0.10), p < 0.05), implying greater symptoms of breathlessness for a given level of V̇e. Both PSF groups had a steeper slope than CDD (0.14 (0.09), p < 0.05 for both comparisons).

Conclusions: Patients with PSF have exercise tolerance intermediate between that of patients with SHF and controls. Exercise tolerance is similar in PSFDD and PSFN. Both groups have worse exercise tolerance than CDD. PSFDD and PSFN patients seem to experience a greater awareness of V̇e than CDD and patients with SHF.

  • CDD, controls with diastolic dysfunction
  • CN, controls with normal diastolic function
  • DD, diastolic dysfunction
  • DHF, diastolic heart failure
  • IVRT, isovolumic relaxation time
  • LV, left ventricular
  • NYHA, New York Heart Association
  • PSF, preserved systolic function
  • PSFDD, preserved systolic function and diastolic dysfunction
  • PSFN, preserved systolic function without diastolic dysfunction
  • pV̇o2, peak oxygen consumption
  • SHF, systolic heart failure
  • co2, carbon dioxide production
  • e, minute ventilation

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Footnotes

  • Published Online First 18 April 2006

  • Financial support: None declared.

  • Competing interests: None declared.

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