Ventilatory gas exchange and early response to cardiac resynchronization therapy

Chul Ho Kim, Lyle J. Olson, Win K. Shen, Yong-Mei Cha, Bruce David Johnson

Research output: Contribution to journalArticle

3 Scopus citations


Background: Cardiac resynchronization therapy (CRT) is an accepted intervention for chronic heart failure (HF), although approximately 30% of patients are non-responders. The purpose of this study was to determine whether exercise respiratory gas exchange obtained before CRT implantation predicts early response to CRT. Methods: Before CRT implantation, patients were assigned to either a mild-moderate group (Mod G, n = 33, age 67 ± 10 years) or a moderate-severe group (Sev G, n = 31, age 67 ± 10 years), based on abnormalities in exercise gas exchange. Severity of impaired gas exchange was based on a score from the measures of VE/VCO<inf>2</inf> slope, resting PETCO<inf>2</inf> and change of PETCO<inf>2</inf> from resting to peak. All measurements were performed before and 3 to 4 months after CRT implantation. Results: Although Mod G did not have improved gas exchange (p > 0.05), Sev G improved significantly (p < 0.05) post-CRT. In addition, Mod G did not show improved right ventricular systolic pressure (RSVP; pre vs post: 37 ± 14 vs 36 ± 11 mm Hg, p > 0.05), yet Sev G showed significantly improved RVSP, by 23% (50 ± 14 vs 42 ± 12 mm Hg, p < 0.05). Both groups had improved left ventricular ejection fraction (p < 0.05), New York Heart Association class (p < 0.05) and quality of life (p < 0.05), but no significant differences were observed between groups (p > 0.05). No significant changes were observed in brain natriuretic peptide in either group post-CRT. Conclusion: Based on pre-CRT implantation ventilatory gas exchange, subjects with the most impaired values appeared to have more improvement post-CRT, possibly associated with a decrease in RVSP.

Original languageEnglish (US)
JournalJournal of Heart and Lung Transplantation
StateAccepted/In press - 2015


  • Exercise
  • Heart failure
  • Pulmonary hypertension
  • Right ventricle pressure
  • Ventilatory efficiency

ASJC Scopus subject areas

  • Transplantation
  • Cardiology and Cardiovascular Medicine
  • Pulmonary and Respiratory Medicine
  • Surgery

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