Cardiac reserve in the transplanted heart: effect of a graft polymorphism in the beta1-adrenoceptor.
| Autor: | Scharin Täng M; Department of Molecular and Clinical Medicine/Cardiology, Wallenberg Laboratory, Sahlgrenska Academy at Göteborg University, Göteborg, Sweden. meta@wlab.gu.se, Lindberg E, Grüner Sveälv B, Magnusson Y, Andersson B |
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| Jazyk: | angličtina |
| Zdroj: | The Journal of heart and lung transplantation : the official publication of the International Society for Heart Transplantation [J Heart Lung Transplant] 2007 Sep; Vol. 26 (9), pp. 915-20. |
| DOI: | 10.1016/j.healun.2007.07.004 |
| Abstrakt: | Background: Polymorphism of the beta1-adrenoceptor (beta1-AR) affects outcome and beta-blocker efficacy in patients with heart failure. We studied the influence of the beta1-AR Ser49Gly polymorphism on cardiac reserve in transplanted hearts. Methods: Beta1-AR polymorphism was determined by allelic discrimination analysis. Patients were divided into two groups: either homozygous for Ser49 (n = 15) or with Gly49 in one or both alleles (Gly49; n = 5). Patients underwent a maximal bicycle exercise test and echocardiographic evaluation at rest and during low-dose dobutamine stress. Results: Patients with Gly49 grafts had better physical endurance (144 +/- 26 vs 112 +/- 31 W, p = 0.03), a trend toward better chronotropic reserve (deltaHR 64 +/- 13 vs 47 +/- 16 bpm, p = 0.056) during exercise, and lower resting heart rate (82 +/- 7 vs 90 +/- 7 bpm, p = 0.04) than those homozygous for Ser49. There were no significant differences in left ventricular ejection fraction (LVEF), with the exception of a decrease in cardiac reserve in patients with the Gly49 variants at the lowest dose of dobutamine (deltaLVEF -4.4 +/- 1.5 vs 2.2 +/- 5.8%, p = 0.04). Doppler myocardial tissue velocities of early relaxation were increased in patients with the Gly49 variants compared with patients homozygous for Ser49, both at rest (14.5 +/- 3.2 vs 10.4 +/- 2.0 cm/s, p = 0.03) and during the lowest dose of dobutamine (15.0 +/- 3.7 vs 10.9 +/- 2.5 cm/s, p = 0.04). Conclusions: Heart transplant patients with the beta1-AR Gly49 variants had a lower heart rate, and better stress endurance and diastolic function compared with patients homozygous for Ser49. They also showed a trend toward better chronotropic reserve. These results provide a possible explanation for differences in cardiac reserve among patients with heart transplants. |
| Databáze: | MEDLINE |
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