Factors influencing immediate and long-term outcome of electrical cardioversion of persistent atrial fibrillation and flutter.

BACKGROUND: To investigate which factors influence the immediate and long-term outcome of elective electrical cardioversion for persistent (>48h) atrial fibrillation or flutter. METHODS: In 255 patients, 435 electrical cardioversions were performed. Relevant clinical, electrocardiographic and echocardiographic factors were registered at each cardioversion. Each factor was tested separately in relation to immediate success and the outcome at six months and one year after cardioversion. RESULTS: In 70% of the patients, sinus rhythm was restored immediately after electrical cardioversion. After six months only 20% of the patients were still in sinus rhythm, and one year after cardioversion this figure had dropped to 14%. Sotalol used during electrical cardioversion resulted in the highest immediate success. Furthermore, atrial flutter, two or fewer electrical shocks and shocks ≤200 Joules resulted in the highest immediate success rate, whilst hypertensive heart disease resulted in the lowest immediate success rate. However, only shocks ≤200 Joules and a first cardioversion promoted the persistence of sinus rhythm after six months. A normal electrocardiogram, two or more cardioversions in the past and the use of a beta-blocking drug other than sotalol during cardioversion increased the chance of recurrence within six months. The duration of the arrhythmia >one month to 200 Joules and more than two cardioversions in the past were associated with a high number of recurrences one year later. With multivariate analysis we found that atrial flutter, low energy levels, low number of shocks and a long QTc-interval influence the immediate success positively. However, no factor influenced the persistence of sinus rhythm at six months and one year. CONCLUSION: In patients with persistent atrial fibrillation or flutter, only about 15% are in sinus rhythm one year after attempted cardioversion. Atrial fibrillation rather than flutter, high energy shocks and previous cardioversions negatively influenced the immediate success of cardioversion. However, none of the clinical, electrocardiographic or echocardiographic baseline factors studied could be identified as playing a role in the prediction of long-term sinus rhythm.

Automated ultrasonic measurement of human arteries for the determination of endothelial function.

AIM: Brachial artery ultrasonography is used to measure flow-mediated dilatation (FMD) as a marker of endothelial function in patients at risk for atherosclerosis. Major disadvantages are the time-consuming manual readings and the high within- and between-observer variability. The authors hypothesize that the ultrasound-based determination of endothelial function can be simplified and refined by an automated analysis system. METHODS AND RESULTS: FMD was quantified by a 7.5 MHz linear transducer following 5 minutes of ischemia of the proximal forearm in 8 healthy volunteers on two occasions. Brachial artery diameter was comparatively assessed 1. manually from the video signal and 2. by a PC-based analyzing system. For the manual readings the mean differences for the FMD were 2.5 +/- 2.3% between-reader, 2.0 +/- 0.9% within-reader and 2.1 +/- 1.5% for scans on different days in contrast to 0.8 +/- 0.4 (between-reader), 0.8 +/- 0.6 (within-reader) and 1.3 +/- 0.9% (day-to-day) for the computerized system. The coefficient of variability for the measurement of arterial diameter was 1.34% for manual readings and 0.78% for the automated analysis system. The mean time for manual readings from S-VHS tapes was 35 minutes in contrast to 9 minutes for the PC-based analysis system. CONCLUSIONS: The new automated analysis system for the boundary detection of the vascular wall reduces the variability and greatly increases the speed of the measurements to determine endothelial function. In future, these advantages will help to screen larger numbers of individuals for endothelial dysfunction, particularly for follow-up and intervention trials, and to reduce the variability between different laboratories.