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Trends in treated ischemic versus nonischemic ventricular fibrillation out-of-hospital cardiac arrest
S114 leading due to a pseudo ‘VAAV’ response. The aim of the present study is to see if inclusion of the timing of the His interval in the electrogram response (ER) following VEP would reliably identify the mechanism of tachycardia in patients with long HV intervals. Methods: Eight patients (7 men) with AVNRT and underlying bundle branch block and long HV intervals underwent electrophysiology study. VEP was performed at 10-40 msec shorter than the tachycardia cycle length in patients with SVT and atrial entrainment was confirmed. The ER was classified as VAAH or VAH depending on the number of entrained atrial electrograms (A) prior to His deflection following VEP. The ER was also classified as VAAV or VAV as previously described by Knight et al (JACC 1999;33:775). Results: The baseline characteristics of the study population were: mean age 68⫾9 yr; mean QRS interval 145⫾25 msec; mean TCL 418⫾67 msec; mean HV interval during SVT 82⫾16 msec; mean HA interval during SVT 65⫾15. The ER following VEP was classified as VAH in all eight patients. However using conventional classification the response was VAAV in 5 of eight patients due to a delayed V secondary to long HV intervals and would erroneously suggest atrial tachycardia. The ER was VAV in only 1 of eight patients. In the remaining two patients the A and V electrograms were simultaneous following the VEP. Conclusions: Incorporating the His electrogram in the electrogram response following VEP would eliminate the pseudo ‘VAAV’ response in patients with AVNRT and long HV intervals. Labeling the response to VEP as ‘VAH’ or ‘VAAH’ is simple and more accurate. P1-29 THROMBOSIS AFTER EP STUDY - A FREQUENT COMPLICATION? Andreas Tiroke, MD, Lars Stracke, MD, Markus Seeger, MD, Markus Lins, MD and Ru¨diger Simon, MD. Kiel, Germany, Kiel, Germany. The risk of thrombosis seems to be increased after an EP-study dependent on the number of used sheaths in the Vena femoralis and the length of the examination. We investigated the incidence of thrombosis after EP study prospectively. Methods: Several sheaths (2-4) of 5-8 french diameter were inserted via Vena femoralis under fluoroscopic controll. The activated clotting time was ⬎ 200 sec (initial Heparin bolus 3000-5000 IE). After completed EP study the sheaths were removed and the patients received a banding for 6 hours. On the next day duplexsonography of the Vena femoralis were performed. The sonographic criteria for thrombosis were direct visualisation of intravascular thrombus, non compressible vessel and increased blood flow velocity. Results: After EP study we examined 148 patients (60 females, 88 males) at an age of 22 - 84 years (mean 55 years ⫾ 16). The mean duration of the EP study was 84 min ⫾ 50 min. Thrombosis was diagnosed in 24 patients (20 %), in 17 men (24 %) and 7 women (14%). The majority of thrombi were located at the dorsal vessel wall of the Vena femoralis consisting of up to 6 cm long throbus (mean length 2,5 cm). In 2 patients we found circular thrombosis, in 1 pateint complete obliteration of the Vena femoralis. Pulmonary embolus was diagnosed in 2 cases. The risk of thrombosis was undependent of the age of the patient (p⫽0,45), duration of the EP study (p⫽0,3), number of used sheaths (p⫽0,29) and gender (p⫽0,25). Conclusion: There is a significant risk of thrombosis after EP study despite using Heparin with controlled ACT.We strongly recommend the use of Heparin during EP study and duplexsonography of the Vena femoralis as a routine follow up. P1-30 TRENDS IN TREATED ISCHEMIC VERSUS NONISCHEMIC VENTRICULAR FIBRILLATION OUT-OF-HOSPITAL CARDIAC ARREST Thomas J. Bunch, MD and Roger D. White, MD. Mayo Clinic, Rochester, MN.
Heart Rhythm, Vol 2, No 5, May Supplement 2005 Background: The incidence of ventricular fibrillation (VF) out-of-hospital cardiac arrest (OHCA) treated by first responders has declined over the past decade. Since VF OHCA occurs primarily in the setting of severe coronary artery disease, primary and secondary prevention strategies may in part account for the decline. However, such strategies may not impact nonischemic arrest equally. Methods: All Rochester City Minnesota residents who presented with a VF OHCA from 1990-2004, treated by emergency medical services (EMS), were included in the study. Incidence rates were calculated based on the population for Rochester City during the time period. Changes over time were tested using Poisson regression models. The significance of the trends was estimated according to the Mantel-Haenszel test for association, and 2-tailed p values reported. Results: The overall incidence of EMS-treated VF OHCA in Rochester during the study period was 10.6 per 100,000 (95% CI 9.1-11.8). The incidence decreased significantly (p⬍0.001) over the study period [19901994: 18.2 / 100,000 (95% CI 13.4-21.9), 1995-1999: 11.8 / 100,000 (95% CI 10.4-17.9), 2000-2004: 8.7 / 100,000 (95% CI 6.0-13.0)]. The incidence of ischemic VF OHCA also declined (1990-1994: 13.4 / 100,000 (95% CI 8.9-16.9), 1995-1999: 11.1 / 100,000 (95% CI 8:2-15.9), 2000-2004: 5.5 / 100,000 (95% CI 3.8-8.2), p⬍0.001. In contrast, the incidence of nonischemic VF OHCA increased (1990-1994: 2.1 / 100,000 (95% CI 1.13-3.1), 1995-1999: 2.3 / 100,000 (95% CI 1.9-3.7), 2000-2004: 2.9 / 100,000, (95% CI 2.0-3.4) p⬍0.001). Conclusion: The incidence of VF OHCA is declining. The decline is attributable to the reduction of ischemic VF cardiac arrest; suggesting an impact of treatment strategies targeted at coronary artery disease. The relative increasing incidence of nonischemic VF OHCA suggests that more efforts are required to minimize mortality in this cohort population. P1-31 MAGNETICALLY-ASSISTED REMOTE DIAGNOSTIC ELECTROPHYSIOLOGY STUDIES USING A SINGLE CATHETER AND NO FLOUROSCOPY *Peter L. Gallagher, MD, Lori Angel, RN, Laura Martin, RN, Aaron Hesselson, MD and *Gery Tomassoni, MD. Central Baptist Hospital, Lexington, KY. Background: Initial studies of the magnetically assisted navigation of catheters and guidewires using the Stereotaxis-Niobe-Artis system have been shown to be safe and effective. The goals of the study were to map and pace in the right atrium (RA), His bundle, right ventricular apex (RVA) and right ventricular outflow tract (RVOT) using remote magnetic navigation without the use of fluoroscopy. Methods: 16 patients were studied with a mean age of 55 yrs, mean LVEF 30 ⫾ 12%, 75% with ischemic and 25% with non-ischemic cardiomyopathy, 31% with a bundle branch block. Intracardiac mapping and pacing was performed with the Tangent (Stereotaxis Inc.) 3-magnet catheter. The catheter was first manually advanced to the RA (confirmed by intracardiac electrograms). A combination of preset and custom magnetic vectors were used to orient the catheter tip and the Stereotaxis Cardiodrive system was then used to remotely advance the catheter to the desired locations. Results: In all 16 patients the catheter could be remotely advanced to the RA, His bundle, RVA and RVOT without the use of flouroscopy. Intracardiac electrograms were used to guide catheter advancement and pacing was used to confirm the appropriate chamber locations. An HV interval was obtained in all patients (48 ⫾ 16 ms). Decremental pacing was performed from the RA and programmed stimulation was performed from the RA, RVA and RVOT. Cardiac sites were confirmed by standard ECG morphology. Sustained ventricular arrhythmias were inducible in 62% of the patients. The mean procedure time was 22.8 ⫾ 8.1 min. There were no complications during or post-procedure. Conclusion: Remote diagnostic EP studies can be safely and efficiently performed using magnetic navigation without the need for fluoroscopy. As 3-dimensional imaging is integrated with magnetic navigation, dramatic reductions in fluoroscopy may be possible during both manual and automated mapping for complex ablations.
Heart Rhythm, Vol 2, No 5, May Supplement 2005 Background: The incidence of ventricular fibrillation (VF) out-of-hospital cardiac arrest (OHCA) treated by first responders has declined over the past decade. Since VF OHCA occurs primarily in the setting of severe coronary artery disease, primary and secondary prevention strategies may in part account for the decline. However, such strategies may not impact nonischemic arrest equally. Methods: All Rochester City Minnesota residents who presented with a VF OHCA from 1990-2004, treated by emergency medical services (EMS), were included in the study. Incidence rates were calculated based on the population for Rochester City during the time period. Changes over time were tested using Poisson regression models. The significance of the trends was estimated according to the Mantel-Haenszel test for association, and 2-tailed p values reported. Results: The overall incidence of EMS-treated VF OHCA in Rochester during the study period was 10.6 per 100,000 (95% CI 9.1-11.8). The incidence decreased significantly (p⬍0.001) over the study period [19901994: 18.2 / 100,000 (95% CI 13.4-21.9), 1995-1999: 11.8 / 100,000 (95% CI 10.4-17.9), 2000-2004: 8.7 / 100,000 (95% CI 6.0-13.0)]. The incidence of ischemic VF OHCA also declined (1990-1994: 13.4 / 100,000 (95% CI 8.9-16.9), 1995-1999: 11.1 / 100,000 (95% CI 8:2-15.9), 2000-2004: 5.5 / 100,000 (95% CI 3.8-8.2), p⬍0.001. In contrast, the incidence of nonischemic VF OHCA increased (1990-1994: 2.1 / 100,000 (95% CI 1.13-3.1), 1995-1999: 2.3 / 100,000 (95% CI 1.9-3.7), 2000-2004: 2.9 / 100,000, (95% CI 2.0-3.4) p⬍0.001). Conclusion: The incidence of VF OHCA is declining. The decline is attributable to the reduction of ischemic VF cardiac arrest; suggesting an impact of treatment strategies targeted at coronary artery disease. The relative increasing incidence of nonischemic VF OHCA suggests that more efforts are required to minimize mortality in this cohort population. P1-31 MAGNETICALLY-ASSISTED REMOTE DIAGNOSTIC ELECTROPHYSIOLOGY STUDIES USING A SINGLE CATHETER AND NO FLOUROSCOPY *Peter L. Gallagher, MD, Lori Angel, RN, Laura Martin, RN, Aaron Hesselson, MD and *Gery Tomassoni, MD. Central Baptist Hospital, Lexington, KY. Background: Initial studies of the magnetically assisted navigation of catheters and guidewires using the Stereotaxis-Niobe-Artis system have been shown to be safe and effective. The goals of the study were to map and pace in the right atrium (RA), His bundle, right ventricular apex (RVA) and right ventricular outflow tract (RVOT) using remote magnetic navigation without the use of fluoroscopy. Methods: 16 patients were studied with a mean age of 55 yrs, mean LVEF 30 ⫾ 12%, 75% with ischemic and 25% with non-ischemic cardiomyopathy, 31% with a bundle branch block. Intracardiac mapping and pacing was performed with the Tangent (Stereotaxis Inc.) 3-magnet catheter. The catheter was first manually advanced to the RA (confirmed by intracardiac electrograms). A combination of preset and custom magnetic vectors were used to orient the catheter tip and the Stereotaxis Cardiodrive system was then used to remotely advance the catheter to the desired locations. Results: In all 16 patients the catheter could be remotely advanced to the RA, His bundle, RVA and RVOT without the use of flouroscopy. Intracardiac electrograms were used to guide catheter advancement and pacing was used to confirm the appropriate chamber locations. An HV interval was obtained in all patients (48 ⫾ 16 ms). Decremental pacing was performed from the RA and programmed stimulation was performed from the RA, RVA and RVOT. Cardiac sites were confirmed by standard ECG morphology. Sustained ventricular arrhythmias were inducible in 62% of the patients. The mean procedure time was 22.8 ⫾ 8.1 min. There were no complications during or post-procedure. Conclusion: Remote diagnostic EP studies can be safely and efficiently performed using magnetic navigation without the need for fluoroscopy. As 3-dimensional imaging is integrated with magnetic navigation, dramatic reductions in fluoroscopy may be possible during both manual and automated mapping for complex ablations.