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. 2020 May;25(3):e12709.
doi: 10.1111/anec.12709. Epub 2019 Oct 8.

Baseline intrinsic heart rate and response to ivabradine treatment in patients with inappropriate sinus tachycardia

Krzysztof Kaczmarek  1 , Thomas Klingenheben  2 , Izabela Poddebska  1 , Irmina Urbanek  1 , Jerzy K Wranicz  1 , Iwona Cygankiewicz  1 , Pawel Ptaszyński  1
Affiliations

Baseline intrinsic heart rate and response to ivabradine treatment in patients with inappropriate sinus tachycardia

Krzysztof Kaczmarek et al. Ann Noninvasive Electrocardiol. 2020 May.

Abstract

Background: Treatment with ivabradine became a new therapeutic alternative for patients with inappropriate sinus tachycardia (IST). The aim was to determine a relation between intrinsic heart rate (IHR) and response to ivabradine treatment.

Methods: Twenty-seven patients (mean age 37 ± 11; 23 women) with symptomatic IST despite medical treatment were recruited into the study. Resting ECG, 24-hr ECG monitoring (24hECG), exercise treadmill test, and symptoms evaluation were performed initially and after 60 days on ivabradine. IHR was acquired at baseline after pharmacological autonomic blockade.

Results: Nineteen patients (70%) were classified as abnormal IHR group (AIHR) while eight showed normal IHR (NIHR). No significant differences in ECG parameters were found between NIHR and AIHR subgroups, while baseline exercise capacity was higher in AIHR patients (10.9 vs. 9.5 METs, p < .05). Ivabradine treatment resulted in significant reduction in resting heart rate, average 24hECG heart rate, improvement in exercise capacity and reduction of symptoms in both subgroups. Nevertheless, favorable influence of ivabradine was significantly more exaggerated in AIHR subgroup (HR 116 vs. 90 bpm, av. HR 98 vs. 79 bpm, 10.9 vs. 13.6 METS, EHRA score 3.1 vs. 1.1, p < .001 for all) than in NIHR patients (HR 112 vs. 98 bpm, av. HR 97 vs. 88 bpm, 9.5 vs. 11.1 METs, EHRA score 3.1 vs. 1.9; p < .05 for all).

Conclusions: Intrinsic heart rate may be useful in predicting response to ivabradine in patients with IST. More intense response to ivabradine in patients with AIHR may be attributed to different pathophysiological mechanisms underlying IST in AIHR and NIHR groups.

Keywords: heart rate; inappropriate sinus tachycardia; ivabradine.

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Conflict of interest statement

No conflict of interest to declare for all authors.

Figures

Figure 1
Figure 1
Study design
Figure 2
Figure 2
Exercise capacity measured with treadmill exercise test
See this image and copyright information in PMC

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