[Factors influencing development of atrial fibrillation after implantation of cardiac pacemaker for sinus node dysfunction]. / Besikartojanciam priesirdziu virpejimui itakos turintys veiksniai, esant sinusinio mazgo disfunkcijai, koreguotai implantavus pastovu elektrokardiostimuliatoriu.

OBJECTIVE: The aim of this study was to evaluate factors influencing the success of atrial fibrillation treatment associated with the sick sinus syndrome after pacemaker implantation. METHODS AND RESULTS: In 163 patients with sick sinus syndrome followed up after pacemaker implantation, statistical analysis showed that the recurrence of atrial fibrillation increased 2.8 times and 2.5 times when the left atrium or the right atrium, respectively, were increased by 1 cm (P=0.001). In addition, the recurrence of atrial fibrillation increased 2.5 times when the interventricular septum was thickened (P=0.007). Probability of atrial fibrillation recurrence was 2.73 times higher in the presence of grade II mitral regurgitation as compared to absent or grade I mitral regurgitation (P=0.029). The results of atrial fibrillation treatment did not significantly depend on age, gender, duration of atrial fibrillation symptoms, other cardiac structural changes, and concomitant noncardiac diseases. CONCLUSIONS: In patients with sick sinus syndrome, the effectiveness of atrial fibrillation treatment after pacemaker implantation is influenced by enlargement of the left and the right atria, increased interventricular septum thickness, and grade II mitral regurgitation. Evaluation of echocardiographic data before pacemaker implantation has prognostic value for determining the probability of maintenance of sinus rhythm.

Blood oxygen saturation during atrio-ventricular dissociation with wide-QRS complex tachycardias.

Amplitude ratios of two adjacent mixed blood oxygen saturation curve peaks in randomly selected strips of ECG were analysed in 32 patients with regular wide-QRS complex tachycardias and 60 control subjects where pacing was performed before ablation of narrow-QRS complex tachycardias. Patients with VT showed different patterns of A-to-V relationships, leading to varying ratios of SpO2 adjacent peak amplitudes, in contrast to patients with aberrant SVTs and 1:1 AV association. Application of a criterion of adjacent SpO2 peaks differing by twofold or more had a sensitivity of 90.0% and specificity of 83.3% to detect AV dissociation during VT. Fluctuations on the mixed oxygen saturation curve may be a useful non-invasive clinical parameter to detect different ventricular filling caused by atrio-ventricular dissociation during VT.

[Radiofrequency modified maze procedure with mitral valve surgery: mid-term follow-up results]. / Modifikuota radiodaznine labirinto procedura ir mitralinio voztuvo ydos korekcija: vidutines trukmes pooperacinio stebejimo rezultatai.

OBJECTIVE: The Cox-maze procedure is an effective established surgical method for elimination of atrial fibrillation. The aim of this study was to evaluate the efficacy and safety of radiofrequency ablation as a surgical adjunct in treating atrial fibrillation and to adapt maze principles to mitral valve surgery using transseptal approaches. MATERIAL AND METHODS: Thirty-six patients underwent radiofrequency modified maze procedure using standard and cooled ablation electrodes in combination with surgery for hemodynamically significant mitral valve disease and chronic, persistent or paroxysmal atrial fibrillation. Fourteen (39%) patients had mitral valve repair and 22 (61%) patients had mitral valve replacement; 33 (91.6%) patients underwent concomitant surgical procedures. RESULTS: The cardiopulmonary bypass time was 162+/-38 min, the aortic cross-clamp time - 98+/-22 min. The additional aortic cross-clamp time required for the radiofrequency modified maze procedure was 21+/-3 min. Postoperative mortality was 2.8%. In 7 of 36 pts (19.4% ) significant bradycardia requiring permanent pacing (six - AAI, one - DDD) was seen after the operation. Patients were followed up for 4 months to 2.5 years after surgery (mean 11.2+/-7.4 months). There were no deaths, no thromboembolic complications during follow-up. Freedom from atrial fibrillation or flutter was 100% at the end of operation, but during 0.5-3 months after operation atrial fibrillation or flutter were observed in 41.6% (15/36) patients. In 2 (5%) patients chronic atrial fibrillation developed. Freedom from atrial fibrillation/flutter was 86% (12/14) at 1 year postoperatively. CONCLUSIONS: The radiofrequency modified maze as an adjunctive procedure is safe and effective in eliminating atrial fibrillation using standard and cooling-tip ablation electrodes in combination with surgery for mitral valve disease.