Limiting esophageal temperature in radiofrequency ablation of left atrial tachyarrhythmias results in low incidence of thermal esophageal lesions

<p>Abstract</p> <p>Background</p> <p>Atrio-esophageal fistula formation following radiofrequency ablation of left atrial tachyarrhythmias is a rare but devastating complication. Esophageal injuries are believed to be precursors of fistula formation and reported to occur in up to 47% of patients. This study investigates the incidence of esophageal lesions when real time esophageal temperature monitoring and temperature limitation is used.</p> <p>Methods</p> <p>184 consecutive patients underwent open irrigated radiofrequency ablation of left atrial tachyarrhythmias. An esophageal temperature probe consisting of three independent thermocouples was used for temperature monitoring. A temperature limit of 40°C was defined to interrupt energy delivery. All patients underwent esophageal endoscopy the next day.</p> <p>Results</p> <p>Endoscopy revealed ulcer formation in 3/184 patients (1.6%). No patient developed atrio-esophageal fistula. Patient and disease characteristics had no influence on ulcer formation. The temperature threshold of 40°C was reached in 157/184 patients. A temperature overshoot after cessation of energy delivery was observed frequently. The mean maximal temperature was 40.8°C. Using a multiple regression analysis creating a box lesion that implies superior- and inferior lines at the posterior wall connecting the right and left encircling was an independent predictor of temperature. Six month follow-up showed an overall success rate of 78% documented as sinus rhythm in seven-day holter ECG.</p> <p>Conclusion</p> <p>Limitation of esophageal temperature to 40°C is associated with the lowest incidence of esophageal lesion formation published so far. This approach may contribute to increase the safety profile of radiofrequency ablation in the left atrium.</p

The Missing Link? U.S. Policy and the International Dimensions of Authoritarian Resilience in the Arab World

In contrast to the hopes of some US observers, the so-called 'Baghdad Spring' of early 2005 did not mark the beginning of an era of sustained political reform in the Middle East. In an attempt to explain the resilience of authoritarian governance in the region, this article aims to demonstrate the insufficiencies of external democratisation efforts that rely on a crude reading of the 'modernisation' school of thinking and ignore the insights of the 'transition' school with regard to the international dimensions of democratisation. Case studies of Egypt and Saudi Arabia, two countries sharing close strategic relationships with the United States yet differing in the socio-economic foundations of authoritarianism and experiences with managing external and domestic calls for political reform, demonstrate that the unwillingness of the United States to condition its support for regional partners on human rights concerns constitutes one of the main reasons for the Arab world's 'democratic exception'