title: Anatomical factors involved in difficult cardiac resynchronization therapy procedure: a non-invasive study using dual-source 64-multi-slice computed tomography.
abstract: OBJECTIVE
  In cardiac resynchronization therapy (CRT) procedure, left ventricular (LV) lead implantation is time consuming. In this clinical setting, no study has investigated the impact of right atrium anatomical parameters on both CRT implantation procedure duration and X-ray exposure. Additionally, only few studies have examined the coronary sinus (CS) using dual-source 64-multi-slice computed tomography (DS 64-MSCT), and its impact on CRT procedure parameters has not yet been investigated. The aim of this prospective study was to identify local anatomical predictive factors of difficult CRT implantation procedure using DS 64-MSCT.
  
  
  RESULTS
  Between January and July 2010, 50 consecutive patients underwent primo CRT implantation. The patient population had a mean age of 70 ± 10 years, and was 34% female, with New York Heart Association Class 3.2 ± 0.3 heart failure, left ventricle ejection fraction 30 ± 4%, and QRS width 157 ± 30 ms. Cardiac resynchronization therapy implantation was attempted in 50 patients, and first LV lead implantation was obtained in 49 of 50 patients (98% primary success). One implantation failed (2%) due to unsuccessful LV lead implant. Procedure parameters were as follows: LV threshold, 1.4 ± 0.8 V; LV wave amplitude, 17 ± 8 mV; LV impedance, 830 ± 240 Ω; median procedure time (skin to skin), 51 min (38 min); median fluoroscopy procedure time, 11.9 min (22 min); and median LV fluoroscopic time, 10.3 min (22 min). In 10 patients (20%), procedures were difficult requiring an implantation lasting ≥ 85 min. The only predictive factor for difficult CRT implantation was the insertion level of the CS ostium (CSO), evaluated by the distance between the CSO and the bottom floor of the right atrium (14.8 ± 4 vs. 9.5 ± 4; P= 0.01). Neither the right atrium dilation nor right ventricular dysfunction was associated with difficult CRT implantation procedures.
  
  
  CONCLUSIONS
  Today, despite improvements in the materials used, problems still remain in the CRT procedure. In this clinical setting, the only predictive factor for very long CRT procedures is the CSO-level insertion (located high). This anatomical anomaly identified by DS 64-MSCT prior to surgery is responsible for 20% of difficult CRT device implantation procedures.
authors: Division of Cardiology, Jean Monnet University, Saint-Etienne, France. dakosta@aol.com
authors: Antoine
authors: A
authors: Da Costa
authors: Alexie
authors: A
authors: Gate-Martinet
authors: Pierre
authors: P
authors: Rouffiange
authors: Alexis
authors: A
authors: Cerisier
authors: Abdallah
authors: A
authors: Nadrouss
authors: Laurence
authors: L
authors: Bisch
authors: Cécile
authors: C
authors: Romeyer-Bouchard
authors: Karl
authors: K
authors: Isaaz
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D059925:Anatomic Landmarks / Q000000981:diagnostic imaging / Q000473:pathology; D057791:Cardiac Imaging Techniques / Q000379:methods*; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D006321:Heart / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D006333:Heart Failure / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000628:therapy; D006801:Humans; D008297:Male; D009206:Myocardium / Q000473:pathology; D011237:Predictive Value of Tests; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors; D014057:Tomography, X-Ray Computed / Q000379:methods*