title: Improved cardiac performance through pacing-induced diaphragmatic stimulation: a novel electrophysiological approach in heart failure management?
abstract: OBJECTIVE
  Pharmacological conditioning of the phrenic nerve can positively influence systolic performance, and diaphragm activation improves ventilatory function. Here we investigate whether pacing-induced diaphragmatic stimulation (PIDS) may improve left ventricular (LV) systolic function.
  
  
  RESULTS
  We studied a total of 35 patients (4 females, mean age 67 +/- 9 years, ejection fraction 61 +/- 14%) within 7 days following open heart surgery. The haemodynamic impact of different PIDS and ventricular pacing configurations and coupling intervals was tested in 132 episodes. Success of PIDS was assessed using fluoroscopy and palpation. Left ventricular systolic performance was recorded using the electromechanical activation time (EMAT) obtained through acoustic cardiography. Eighteen subjects were tested in the catheter laboratory and 17 in the intensive care unit. For both groups, EMAT significantly improved when the diaphragm was stimulated 20 ms after the onset of ventricular pacing. In all instances, PIDS could be induced with or without causing patient symptoms, and LV systolic performance improvement was comparable in symptomatic and asymptomatic modes. No desensitization of the diaphragm was observed following PIDS delivery 4-6 and 24 h following open heart surgery.
  
  
  CONCLUSIONS
  Pacing-induced diaphragmatic stimulation, if synchronized to the onset of ventricular contraction with a fixed, non-zero coupling delay, can improve LV systolic function reproducibly for at least 1 h without causing patient symptoms. The absence of diaphragm desensitization further underscores the potential of PIDS as a practical therapeutic approach in device-based heart failure management.
authors.affiliation: Department of Cardiology, Kantonsspital, Luzern, Luzern, Switzerland.
authors.forename: Markus
authors.initials: M
authors.lastname: Roos
authors.forename: Richard
authors.initials: R
authors.lastname: Kobza
authors.forename: Peiman
authors.initials: P
authors.lastname: Jamshidi
authors.forename: Peter
authors.initials: P
authors.lastname: Bauer
authors.forename: Thérèse
authors.initials: T
authors.lastname: Resink
authors.forename: Reinhard
authors.initials: R
authors.lastname: Schlaepfer
authors.forename: Peter
authors.initials: P
authors.lastname: Stulz
authors.forename: Michel
authors.initials: M
authors.lastname: Zuber
authors.forename: Paul
authors.initials: P
authors.lastname: Erne
mesh_terms: D000368:Aged; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D003964:Diaphragm / Q000502:physiology*; D004566:Electrodes; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods*; D005260:Female; D054143:Heart Failure, Systolic / Q000503:physiopathology / Q000628:therapy*; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D007702:Kinetocardiography; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology / Q000628:therapy