encompassed by ablation lesions was larger in patients with paroxysmal AF who had a successful clinical outcome than in those who did not (32% of total LA area vs. 21%). Conclusions: Circumferential catheter ablation to isolate the PV often eliminates AF (particularly when the AF is parox- ysmal) and has a low risk of serious complications. Perspective: The study confirms the critical importance of the PV in triggering and/or maintaining AF. However, the results suggest that the atrial myocardium adjacent to the PV also may be important. This may explain why the success rate in this study was higher than in studies that have isolated the PV at their ostia, without excluding any atrial myocardium. FM Dispatcher-Assisted Cardiopulmonary Resuscitation and Survival in Cardiac Arrest Rea TD, Eisenberg MS, Culley LL, et al. Circulation 2001;104: 2513– 6. Study Question: How does dispatcher-assisted bystander cardiopulmonary resuscitation (CPR) affect survival after out-of-hospital cardiac arrest? Methods: The subjects of this study were 7265 adults treated by emergency medical services (EMS) for out-of-hospital cardiac arrest in King County, Washington between 1983 and 2000. Records were reviewed to determine whether or not there was bystander CPR before the arrival of EMS, and if so, whether or not it was dispatcher-assisted. Dispatcher assistance consisted of specific instructions communicated by telephone. The end point of the study was survival to hospital discharge. Results: There was no bystander CPR in 44% of subjects, dispatcher-assisted bystander CPR in 26%, and bystander CPR without dispatcher assistance in 30%. The mean time from collapse to CPR was approximately 1 minute longer when bystander CPR was dispatcher-assisted than when it was not. Survival in the entire group was 15%. By multivar- iate analysis, bystander CPR improved the odds of survival either when dispatcher-assisted (odds ratio 1.45) or when not dispatcher-assisted (odds ratio 1.69). Statistical model- ing indicated that most of the survival benefit of bystander CPR was attributable to a shorter time from collapse to CPR. Conclusions: Bystander CPR significantly increases survival after out-of-hospital cardiac arrest, whether or not it is dispatcher assisted. Perspective: The results of the study underscore the impor- tance of bystander CPR in improving survival after out-of- hospital cardiac arrest. Apparently even only 1 minute of verbal instruction in CPR transmitted by telephone to an inexperienced bystander is enough to significantly improve the odds of survival. The results make a strong case for aggressive efforts at educating the public in CPR. FM Out-of-Hospital Cardiac Arrest in Men and Women Kim C, Fahrenbruch CE, Cobb LA, Eisenberg MS. Circulation 2001;104:2699 –703. Study Question: How does gender affect survival after out-of- hospital cardiac arrest? Methods: This study was a retrospective review of the cardiac arrest databases in Seattle and King County, Washington. The subjects were patients 30 years of age who were treated by paramedics for cardiac arrest between 1990 and 1998. Results: There were 3810 women and 7069 men who met the selection criteria of the study. The annual incidence of cardiac arrest was lower in women than in men (0.08% vs. 0.16%). The women were older (71 vs. 66 years), less often had ventricular fibrillation (VF) as the initial rhythm (25 vs. 43%) and more often had pulseless electrical activity (PEA) or asystole as the initial rhythm (73 vs. 55%). Women had a lower survival to hospital admission (29 vs. 32%) and a lower survival to hospital discharge (11 vs. 15%). However, when adjusted for VF, women had a higher resuscitation rate than men (odds ratio 1.13). This gender difference was greatest between the ages of 30 and 39 years, and dimin- ished in older patients. When adjusted for VF, gender had no effect on survival to hospital discharge. Conclusions: Women with out-of-hospital cardiac arrest less often have VF as the initial rhythm, and this accounts for their lower unadjusted resuscitation and survival rates com- pared to men. When adjusted for VF, younger women have a higher survival to hospital admission than men and sur- vival to hospital discharge is similar in women and men. Perspective: The gender difference in the prevalence of VF suggests that women may more often have noncardiac causes of cardiac arrest that are more likely to cause PEA/ asystole than VF. The interaction between age, gender and resuscitation rate suggests that sex hormones provide a survival advantage. The mechanisms underlying this inter- action are unclear and require further study. FM Impact of Cardiac Revascularization Therapy Using Hemodynamically Optimized Pacing on Left Ventricular Remodeling in Patients With Congestive Heart Failure and Ventricular Conduction Disturbances Stellbrink C, Breithardt OA, Franke A, et al. J Am Coll Cardiol 2001;38:1957– 65. Study Question: Do baseline echocardiogram parameters predict the long-term response to cardiac resynchroniza- tion therapy (CRT) in patients with heart failure (HF)? Methods: Twenty-five patients with New York Heart Associ- ation class III or IV HF and a QRS duration 120 ms underwent either right ventricular (12%), left ventricular (40%) or biventricular (48%) pacing, depending on which pacing modality provided the best acute hemodynamic ACC CURRENT JOURNAL REVIEW May/Jun 2002 72