Aernout Somsen

Publications (2)6.08 Total impact

• Article: Improvement in cardiac sympathetic nerve activity in responders to resynchronization therapy.

  Haran Burri, Henri Sunthorn, Aernout Somsen, Eric Fleury, Carine Stettler, Dipen Shah, Alberto Righetti
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  ABSTRACT: To assess changes in cardiac adrenergic activity with cardiac resynchronization therapy (CRT), and to investigate whether these changes are related to improvement in left ventricular ejection fraction (LVEF). Sixteen patients (13 males, age 66 +/- 7 years) were studied at baseline and after > or =6 months of CRT (mean follow-up 9.2 +/- 3.2 months). LVEF was assessed by nuclear angiography. Responders were defined as patients showing > or =5% absolute increase in LVEF + improvement in > or =1 NYHA class + absence of heart failure hospitalization. Cardiac sympathetic nerve activity was studied by (123)I-metaiodobenzyl-guanidine ((123)I-MIBG) scintigraphy. Responders (n = 8) showed lower (123)I-MIBG washout at follow-up when compared with non-responders (P = 0.002), indicating lower cardiac sympathetic nerve activity. The decrease in (123)I-MIBG washout at follow-up when compared with baseline was only seen in the responder group (P = 0.036). There was a moderate correlation between increase in LVEF and decrease in (123)I-MIBG washout (r = 0.52, P = 0.04). CRT induces a reduction in cardiac sympathetic nerve activity in responders, that parallels an improvement in LVEF, whereas non-responders do not show any significant changes.
  Europace 03/2008; 10(3):374-8. · 1.98 Impact Factor
• Article: Optimizing sequential biventricular pacing using radionuclide ventriculography.

  Haran Burri, Henri Sunthorn, Aernout Somsen, Stéphane Zaza, Eric Fleury, Dipen Shah, Alberto Righetti
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  ABSTRACT: Biventricular pacemakers are usually programmed with the default setting of synchronous biventricular pacing, although the ventricles may be paced sequentially. Whether this parameter is important for optimizing resynchronization therapy is not clear. The purpose of this study was to investigate whether sequential pacing acutely improves left ventricular ejection fraction (LVEF) and dyssynchrony and to assess the feasibility of nuclear ventriculography for device optimization. Twenty-seven patients implanted with a biventricular pacemaker or implantable cardioverter-defibrillator for heart failure were studied. LVEF was measured using planar radionuclide ventriculography during simultaneous biventricular pacing and during sequential pacing at four different interventricular intervals ranging from LV-40 (preexciting the left ventricle by 40 ms) to LV+40 (preexciting the right ventricle). Interventricular and intraventricular dyssynchrony were analyzed by phase analysis at each setting. There was great heterogeneity in individual response to VV interval programming. Twenty-four of 27 patients (89%) had significant changes (both favorable and unfavorable) in LVEF at different interventricular delays, with variations of up to 10% in absolute terms. Simultaneous biventricular pacing yielded maximal LVEF in 9 of 27 patients (33%), with a relative increase in LVEF of 18 +/- 14% by optimized sequential pacing in the remaining patients. Interventricular dyssynchrony varied significantly, with least dyssynchrony at the LV-20 setting (P = .024). There were no significant differences in intraventricular dyssynchrony at the different settings. Programming VV intervals has considerable impact on LVEF. However, there is a great degree of variation between patients in response to these settings, requiring individual assessment for device optimization.
  Heart Rhythm 10/2005; 2(9):960-5. · 4.10 Impact Factor