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  • 1
    In: American Journal of Physiology-Heart and Circulatory Physiology, American Physiological Society, Vol. 297, No. 1 ( 2009-07), p. H233-H237
    Abstract: In a previous study we demonstrated that the institution of biventricular pacing in chronic heart failure (CHF) acutely facilitates the arterial baroreflex. The arterial baroreflex has important prognostic value in CHF. We hypothesized that the acute response in baroreflex sensitivity (BRS) after the institution of cardiac resynchronization therapy (CRT) has predictive value for midterm response. One day after implantation of a CRT device in 33 CHF patients (27 male/6 female; age, 66.5 ± 9.5 yr; left ventricular ejection fraction, 28 ± 7%) we measured noninvasive BRS and heart rate variability (HRV) in two conditions: CRT device switched on and switched off (on/off order randomized). Echocardiography was performed before implantation (baseline) and 6 mo after implantation (follow-up). CRT responders were defined as patients in whom left ventricular end-systolic volume at follow-up had decreased by ≥15%. Responders (69.7%) and nonresponders (30.3%) had similar baseline characteristics. In responders, CRT increased BRS by 30% ( P = 0.03); this differed significantly ( P = 0.02) from the average BRS change (−2%) in the nonresponders. CRT also increased HRV by 30% in responders ( P = 0.02), but there was no significant difference found compared with the increase in HRV (8%) in the nonresponders. Receiver-operating characteristic curve analysis revealed that the percent BRS increase had predictive value for the discrimination of responders and nonresponders (area under the curve, 0.69; 95% confidence interval, 0.51–0.87; maximal accuracy, 0.70). Our study demonstrates that a CRT-induced acute BRS increase has predictive value for the echocardiographic response to CRT. This finding suggests that the autonomic nervous system is actively involved in CRT-related reverse remodeling.
    Type of Medium: Online Resource
    ISSN: 0363-6135 , 1522-1539
    RVK:
    Language: English
    Publisher: American Physiological Society
    Publication Date: 2009
    detail.hit.zdb_id: 1477308-9
    SSG: 12
    Location Call Number Limitation Availability
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  • 2
    Online Resource
    Online Resource
    American Physiological Society ; 2008
    In:  American Journal of Physiology-Heart and Circulatory Physiology Vol. 295, No. 2 ( 2008-08), p. H755-H760
    In: American Journal of Physiology-Heart and Circulatory Physiology, American Physiological Society, Vol. 295, No. 2 ( 2008-08), p. H755-H760
    Abstract: Metabolic and mechanical stress in the failing heart activates the cardiac sympathetic afferent reflex (CSAR). It has been demonstrated that cardiac resynchronization therapy (CRT) acutely reduces MSNA in clinical responders. Mechanistically, this beneficial effect might be explained by acute deactivation of the CSAR. In addition to sympathoexcitation, CSAR inhibits the arterial baroreflex at the level of the nucleus tractus solitarii. Hence, in responders, CRT is likely to remove/reduce this inhibition. Therefore, we hypothesized that CRT acutely facilitates the arterial baroreflex. One day after implantation of a CRT device in 32 patients with chronic heart failure (LVEF; 27 ± 6%), we measured noninvasive baroreflex sensitivity (BRS) and heart rate variability (HRV) in two conditions: CRT device switched on and switched off (on/off order randomized). BRS changes were correlated with the difference in unpaced/paced LVEF, a measure of acute mechanical response to CRT. CRT increased BRS by 35% from 2.96 to 3.79 ms/mmHg ( P 〈 0.02) and increased HRV (standard deviation of the intervals between normal beats) from 18.5 to 24.0 ms ( P 〈 0.01). The CRT-induced relative change in BRS correlated with the change in LVEF ( r = 0.44; P 〈 0.01). In conclusion, CRT acutely increases BRS and HRV. This favorable response of the autonomic nervous system might be caused by CRT-induced CSAR deactivation. Follow-up studies should verify the mechanism of the acute response and the possible predictive value of an acute positive BRS response.
    Type of Medium: Online Resource
    ISSN: 0363-6135 , 1522-1539
    RVK:
    Language: English
    Publisher: American Physiological Society
    Publication Date: 2008
    detail.hit.zdb_id: 1477308-9
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
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