[Early haemodynamic changes after radiofrequency ablation of the atrioventricular junction]. / Vcasné hemodynamické zmeny po rádiofrekvencnej ablácii predsienovokomorového spojenia.

INTRODUCTION: The effect of radiofrequency ablation of the atrioventricular junction may be accompanied by undesired effect of right ventricular stimulation. The objective of the study was to evaluate early haemodynamic effects of catheter ablation in patients with permanent atrial fibrillation resistant to pharmacotherapy. METHOD: The study included 19 patients aged 66.9 +/- 12.4 years on an average. Depending on the basal ejection fraction (EF), we divided the patients in to two groups (the 1 st group patients had EF less than 50 %, the 2nd group patients had EF equal to 50 % or higher). The patients were underwent radiofrequency ablation of the atrioventricularjunction and a pacemaker implantation. Haemodynamic changes were evaluated by measuring the ejection volume (EV) and the minute volume (MV) using echocardiography basally prior to and after the intervention, at different stimulation frequencies. For a more precise evaluation of the patients' condition, we defined the EVi am MVi indices as the ratio between the above values at different stimulation frequencies and the basal value. OUTCOME: EV in patients with a low EF increases at all stimulation frequencies with the maximum effect observed in the frequency band from 60-100/min. At stimulation frequency of 60/min, the volume increased from 26.4 ml before ablation to 39.5 ml after ablation. MV grows or remains unchanged at all frequencies except for 60/min, at which the growth in EV cannot compensate the drop in MV due to a fall in frequency. Patients in the 2nd group had a high EV value (52.3 ml) before ablation. After the intervention, their EV increased only at stimulation frequency of 60 and 80/min (64.0 and 55.1 ml, respectively). Also these patients' MV was high before ablation (6,097 ml). After the intervention, their MV decreased for all stimulation frequencies, but showed a growing tendency. Statistical evaluation showed negative correlation between EVi and MVi on the one hand, and between EF and the average of the left ventricle in systole on the other. CONCLUSION: Our results have shown that radiofrequency transcatheter ablation of the atrioventricular node (RFCA AVN) is beneficial for certain patients in both the groups, even though the mechanisms of improving their clinical condition are different.

[Trends in indications for permanent cardiac pacing therapy at the Cardiac Pacing Center in Eastern Slovakia 1978-1994]. / Vývoj indikácií trvalej kardiostimulacnej liecby v kardiostimulacnom centre východného Slovenska v rokoch 1978 az 1994.

At the Third Medical Clinic, which acts as a cardiostimulation centre for the eastern Slovak area, in 1978 to 1994 1 581 primary implantations and 996 reimplantations of pacemakers were made. In the group of primary implantations the mean age of patients was 70.7 +/- 10.9 years, the male/female ratio was 850/731. In the group of reimplantations the mean age was 71.3 +/- 11.6 years, incl. 483 men and 513 women. There is an almost linear rise of primoimplantations. In the group of reimplantations we can observe a two-peak shape of the curve with a maximum in 1986 and in 1990. While in 1978 atrioventricular block grade III accounted for almost 90% indications for primary implantations, during subsequent years its ratio declined gradually and at present it has reached a steady level of 30-40%. The second most frequent dysrhythmia in the group is dysfunction of the sinoatrial node which in 1978 accounted for 6% of the indications, while in 1994 it accounts for 28% of the primary implantations. In 1978 only non-programmable pacemakers VVI/V00 were implanted. In 1989 on a wider scale multiprogrammable ventricular single electrode systems VVIM were introduced which in 1994 accounted for 58% of the implanted pacemakers. Stimulation with adaptable frequency (VVIR, AAIR) and physiological stimulation of two cavities incl. VDD stimulation accounted for 42% in 1994. It can be summarized that during the last five years marked extension of physiological stimulation occurred with an opportunity to select the optimal mode of stimulation, to increase reliability and keeping qualities of the implanted pacemakers and to improve the perspectives of patients needing cardiostimulation therapy.

[Ventricular fibrillation after administration of adenosine]. / Komorová fibrilácia po aplikácii adenozínu.

In the submitted case-history the authors describe a hitherto unknown proarrhythmic effect of adenosine. Adenosine was administered on account of supraventricular tachycardia and the undesirable proarrhythmic effect was so-called "sine wave-like tachycardia" and ventricular fibrillation. Proarrhythmia was resistant to electric cardioversion and resuscitation was successful probably only after the breakdown of adenosine. The very short half-life of breakdown of this antiarrhythmic is thus useful not only for antiarrhythmic strategy but, because of the possible occurrence of rare proarrhythmias, adenosine holds a preferential position among other antiarrhythmic drugs.