A Novel and Simple Exercise Test Parameter to Assess Responsiveness to Cardiac Resynchronization Therapy

Abstract

This study assessed the value of heart rate recovery index (HRRI), a new parameter of an exercise test, as the predictor of response to cardiac resynchronization therapy (CRT). Methods: Consecutive patients receiving a CRT device were followed up after implantation and every 6 months. An effort test (ET) was quantified by minimum heart rate/maximum heart rate, as well as acceleration and deceleration times. HRRI was calculated as the ratio between acceleration and deceleration time (AT/DT) and compared to outcome. We used logistic regression to assess the predictive value of HRRI for responders and non-responders to CRT. The area under the curve (AUC) was computed to distinguish between positive and negative outcomes. Results: A total of 109 patients (74 men, mean age 63.3 ± 9.8 years) were analyzed; permanent long-term fusion CRT pacing was possible in 65 patients. Patients were assigned to two groups: responders and non-responders (98/11 patients). During a mean follow-up of 36 months, 545 ETs were performed. HRRI was significantly higher in responders versus non-responders (3.16 ± 2 vs. 1.4 ± 0.5, p < 0.001). The optimal cutoff value for HRRI as a predictor of CRT response was 1.51 (area under the receiver operating characteristic (ROC) curve = 0.844). Responders had significant left-ventricular (LV) reverse remodeling (LV end-diastolic volume = 240 ± 90 mL vs. 217 ± 89 mL, p < 0.001) and higher LV ejection fraction (26 ± 5.8% vs. 35 ± 8.7%, p < 0.001). Conclusions: HRRI computation during routine ET is useful for the evaluation of responsiveness to CRT.

Heart Rate Recovery: Up to Date in Heart Failure—A Literature Review

“…The former implied symptom-limited CPET that was conducted on patients who presented with acute decompensated heart failure (ADHF), after the clinical stabilization of the patients [29]. The latter showed that an increased HRRI was associated with responder status, while a blunted HRRI was linked to non-responders in CRT patients [35]. The presented data from the numerous studies have covered diverse study groups, comprising patients from all HF stages [48].…”

“…Heart rate recovery index —measured as the ratio between heart rate acceleration time (AT) and heart rate deceleration time (DT) [ 35 ].…”

“…Delving into HRR determination methods, the most frequently used methods are represented by HRR1 and HRR2. Cozlac et al used another determinant, namely the heart rate recovery index (HRRI) [ 35 ]. This index evaluates both the exercise time, by assessing the heart rate acceleration time (AT), and the time of recovery, by measuring the heart rate deceleration time (DT), being defined as the ratio between AT and DT.…”

The potential benefits of assessing post-cardiopulmonary exercise testing (CPET) in aging: a narrative review

“…Heart rate recovery index (HRRI) is another measure of HRR and is defined as the ratio of acceleration time of HR during exercise (time from baseline HR to HR max) to the deceleration time of HR (time from HR max to baseline HR) post-CPET [ 50 ]. Cozlac and colleagues [ 50 ] assessed whether HRRI can be used to predict the response of cardiac patients to cardiac resynchronization therapy, a therapy to normalize patients’ heart rhythm. They found that responders and non-responders to cardiac resynchronization therapy had significant differences in HRRI post-CPET [ 50 ].…”

“…Cozlac and colleagues [ 50 ] assessed whether HRRI can be used to predict the response of cardiac patients to cardiac resynchronization therapy, a therapy to normalize patients’ heart rhythm. They found that responders and non-responders to cardiac resynchronization therapy had significant differences in HRRI post-CPET [ 50 ]. The differences were associated with the cardiac phenotype and function, where responders to cardiac resynchronization therapy had significant left ventricular reverse modelling and larger left ventricular ejection fraction as compared to non-responders [ 50 ].…”