Evaluation of Breath-Holding Test in Assessment of Peripheral Chemoreflex Sensitivity in Patients with Chronic Heart Failure

BACKGROUND: The sensitivity of peripheral chemoreflex is a marker of the severity of heart failure and the prognosis of the outcome in these patients. The assessment of chemosensitivity in these patients remains an actual problem. OBJECTIVE: The aim of the study was to explore the relationship between a Breath-Holding Test (BHT) and single-breath carbon dioxide test and to evaluate the reliability of both tests in patients with Heart Failure (HF). METHOD: The study was performed in 43 patients with chronic heart failure. All subjects underwent BHT and single-breath carbon dioxide (CB-CO(2)), the evaluation of both tests was repeated a month later. Relationship of two test was evaluated by correlation analysis. Reliability was assessed with calculation of Standard Error of Measurement (SEM), Coefficient of Variation (CV) and Intraclass Correlation Coefficient (ICC). RESULTS: The duration of the breath-holding was inversely correlated to the result of CB-CO(2) test (r = -0.86 at first measurement and r = -0.79 after a month) The ICC was 0.87 (95%CI: 0.78–0.93) for SB-CO(2) test and 0,93 (95%CI: 0.88–0.96) for BHT, the CV was 24% for SB-CO(2) and 13% for BHT. SEM for SB-CO(2) test was 0.04 L / min / mmHg and limits of variation was 0.11 L / min / mmHg; SEM for BHT was 3.6 sec and limits of variation was10 sec. CONCLUSION: Breath-holding test is a reliable and safe method for assessing the sensitivity of peripheral chemoreflex to carbon dioxide in patients with heart failure.