A trial fibrillation (AF) is the most common human arrhythmia and is associated with increased risk for ischemic stroke and cardiovascular mortality. The pulmonary veins (PV) are important trigger sites of paroxysmal AF, 1 and their electric isolation from the left atrium (LA) is associated with a high rate of freedom from AF in patients without comorbidities.2 In persistent AF, however, additional arrhythmogenic atrial sites are responsible for AF maintenance and pulmonary vein isolation (PVI) is much less successful with reported 5-year AF freedom rate of 20% after a single and 45% after multiple procedures.3,4 Additional ablation strategies have been developed to improve outcomes including linear lesions and ablation of complex-fractionated atrial electrograms (CFAE) in the left and right atrium (RA), both as a stand-alone approach 5 or in addition to PV isolation. 6 Albeit improving the rate of AF-free survival in some studies, these ablation strategies are inconsistent because of the variable definition and significance of CFAE and require prolonged radiofrequency delivery times. Moreover, the recent multicenter trial, Substrate and Trigger Ablation for Reduction of Atrial Fibrillation 2 (STAR AF 2), did not reveal significant differences in rate of arrhythmia freedom between PVI only versus PVI+CFAE ablation versus PVI+linear ablation: all the 3 strategies resulted in a 1-year arrhythmia freedom of about 50%. 8,9 Recent clinical and experimental studies have identified more specific electrograms in a discrete point or within a region suggestive of a localized reentry during ongoing AF and have been associated with higher ablation impact on AF. Original ArticleBackground-Complex-fractionated atrial electrograms and atrial fibrosis are associated with maintenance of persistent atrial fibrillation (AF). We hypothesized that pulmonary vein isolation (PVI) plus ablation of selective atrial low-voltage sites may be more successful than PVI only. Methods and Results-A total of 85 consecutive patients with persistent AF underwent high-density atrial voltage mapping, PVI, and ablation at low-voltage areas (LVA<0.5 mV in AF) associated with electric activity lasting >70% of AF cycle length on a single electrode (fractionated activity) or multiple electrodes around the circumferential mapping catheter (rotational activity) or discrete rapid local activity (group I). The procedural end point was AF termination. Arrhythmia freedom was compared with a control group (66 patients) undergoing PVI only (group II). PVI alone was performed in 23 of 85 (27%) patients of group I with low amount (<10% of left atrial surface area) of atrial low voltage. Selective atrial ablation in addition to PVI was performed in 62 patients with termination of AF in 45 (73%) after 11±9 minutes radiofrequency delivery. AF-termination sites colocalized within LVA in 80% and at border zones in 20%. Singleprocedural arrhythmia freedom at 13 months median follow-up was achieved in 59 of 85 (69%) patients in group I, which was significantly higher th...

Atrial fibrosis as defined by DE MRI is associated with slower and more organized electrical activity but with lower voltage than healthy atrial areas. Ninety percent of continuous CFAE sites occur at non-DE and patchy DE LA sites. These findings are important when choosing the ablation strategy in persistent AF.

It has been suggested that the morbidity associated with cardiopulmonary bypass can be attributed in part to the blood-material and blood-air interactions in the extracorporeal circulation (ECC). A recently introduced minimized ECC-system (MECC System) should be able to reduce these negative effects associated with ECC. A retrospective analysis was performed comprising 485 patients who were operated on for elective coronary artery bypass grafting (CABG) using the MECC System with intermittent antegrade warm blood cardioplegia (group 1) from January 2000 to February 2004. A control group consisted of 485 patients (group 2) undergoing elective CABG in the same period using a conventional ECC and cold crystalloid cardioplegia. There were no significant differences between the two groups in terms of the duration of intubation following surgery, the length of intensive care unitstay and the total hospital stay. Although the 30-day mortality was similar between the two groups, the incidence of postoperative complications and the perioperative use of blood products were significantly higher in the control group compared to the MECC group. The MECC System may serve as an alternative and less invasive approach to conventional ECC.

Although arterial pressure-derived SVV revealed the best correlation to volume-induced changes in SVI, the results of our study suggest that both variables, SVV and PVI, can serve as valid indicators of fluid responsiveness in mechanically ventilated patients undergoing major surgery.

We have analysed the clinical agreement between two methods of continuous cardiac output measurement pulse contour analysis (PCCO) and a continuous thermodilution technique (CCO), were both compared with the intermittent bolus thermodilution technique (BCO). Measurements were performed in 26 cardiac surgical patients (groups 1 and 2, 13 patients each, with an ejection fraction > 45% and < 45%, respectively) at 12 selected times. During operation, mean differences (bias) between PCCO-BCO and CCO-BCO did not differ in either group. However, phenylephrine-induced increases in systemic vascular resistance (SVR) by approximately 60% resulted in significant differences. Significantly higher absolute bias values of PCCO-BCO compared with CCO-BCO were also found early after operation in the ICU. Thus PCCO and CCO provided comparable measurements during coronary bypass surgery. After marked changes in SVR, further calibration of the PCCO device is necessary.