| Title | Right ventricular pacing improves right heart function in experimental pulmonary arterial hypertension: a study in the isolated heart. | | Author(s) | Handoko ML, Lamberts RR, Redout EM, de Man FS, Boer C, Simonides WS, Paulus WJ, Westerhof N, Allaart CP, Vonk-Noordegraaf A | | Institution | VU University Medical Center / Institute for Cardiovascular Research. | | Source | Am J Physiol Heart Circ Physiol 2009 Sep 4. | | Abstract | Right heart failure in pulmonary arterial hypertension (PH) is associated with mechanical ventricular dyssynchrony, which leads to impaired right ventricular (RV) function, and - by adverse diastolic interaction - to impaired left ventricular (LV) function as well. However, therapies aiming to restore synchrony by pacing are currently not available. In this proof-of-principle study, we determined the acute effects of RV-pacing on ventricular dyssynchrony in PH. Chronic PH with right heart failure was induced in rats by injection of monocrotaline (80 mg/kg). To validate for PH-related ventricular dyssynchrony, rats (6 PH, 6 controls) were examined by cardiac magnetic resonance imaging (9.4 Tesla), twenty-three days after monocrotaline- or sham-injection. In a second group (10 PH, 4 controls), the effects of RV-pacing were studied in detail, using Langendorff-perfused heart preparations. In PH, septum bulging was observed, coinciding with a reversal of the trans-septal pressure gradient, as observed in clinical PH. RV-pacing improved RV systolic function, compared to unpaced condition (RV dP/dtmax: +8.5+/-1.3 %, p<0.001). In addition, RV-pacing markedly decreased PTI RVP>LVP, an index of adverse diastolic interaction (-24+/-9 %, p<0.01), and RV-pacing was able to resynchronize time of RV and LV peak-pressure (Deltat peak, unpaced: 9.8+/-1.2 ms vs. paced: 1.7+/-2.0 ms, p<0.001). Finally, RV-pacing had no detrimental effects on LV function or coronary perfusion, and no LV pre-excitation occurred. Taken together, we demonstrate that in experimental PH, RV-pacing improves RV function and diminishes adverse diastolic interaction. These findings provide a strong rationale for further in vivo explorations. Key words: pulmonary hypertension, right ventricular dysfunction, artificial cardiac pacing, magnetic resonance imaging. | | Language | ENG | | Pub Type(s) | JOURNAL ARTICLE
| | PubMed ID | 19734361 |
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