title: A clinical phenotype of adverse response to biventricular pacing: a case series.
abstract: BACKGROUND
  Biventricular pacing is an established therapy for patients with heart failure with reduced left ventricular ejection fraction and prolonged QRS duration. However, there are few reports on the adverse effects of biventricular pacing.
  
  
  METHODS
  Three patients who deteriorated rapidly following biventricular pacing (heart transplantation/ventricular assist device within 3 months of device implantation) were identified. The clinical, echocardiographic, and functional characteristics before and after device implantation were evaluated. The acute hemodynamic effects of biventricular pacing were assessed by cardiac catheterization.
  
  
  RESULTS
  Preimplant assessment showed biventricular dysfunction, pulmonary hypertension, and relatively narrow QRS duration. The time from device implantation to assessment was 62, 58, and 42 days. All three patients developed right bundle branch block (RBBB)-type QRS morphology, deterioration in right ventricular (RV) function, and functional capacity in association with rapid clinical decline. Acutely, biventricular pacing resulted in higher right atrial pressure, pulmonary wedge pressure, lower cardiac output, and RV stroke work in all three patients.
  
  
  CONCLUSIONS
  A phenotype of adverse response to biventricular pacing is characterized by relatively narrow QRS duration, RV dysfunction, and pulmonary hypertension. Clinical decline is rapid and associated with the development of RBBB-type morphology, worsening of pulmonary hemodynamics, and RV dysfunction with biventricular pacing.
authors.affiliation: University Hospital Birmingham NHS Trust, Edgbaston, Birmingham, UK. hsern@doctors.net.uk
authors.forename: Hoong Sern
authors.initials: HS
authors.lastname: Lim
mesh_terms: D000328:Adult; D002037:Bundle-Branch Block / Q000209:etiology; D006328:Cardiac Catheterization; D002302:Cardiac Output; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects*; D004452:Echocardiography; D004562:Electrocardiography; D006333:Heart Failure / Q000503:physiopathology / Q000628:therapy*; D016027:Heart Transplantation; D006353:Heart-Assist Devices; D006801:Humans; D006976:Hypertension, Pulmonary / Q000209:etiology; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D011669:Pulmonary Wedge Pressure; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology / Q000628:therapy*