Biomedical subjects

Attila Róka

Publications and source records attributed to Attila Róka.

6 recordsLinked to original sources

PubMed2006

Short-term effect of rate control on plasma endothelin levels of patients with tachyarrhythmias.

Radiofrequency catheter ablation or modification of the atrio-ventricular junction is an effective therapy of drug refractory supraventricular tachyarrhythmias (ST). Higher endothelin (ET) levels were observed during nonsustained STs. We aimed to examine the effect of sustained STs and the applied rate-control therapy on plasma ET levels. Twenty-two patients (12 men; mean age, 64.4 +/- 13.2 years; ejection fraction, 41.8 +/- 11.2%; New York Heart Association (NYHA) class I: 3 cases, NYHA II: 11 cases, and NYHA III: 8 cases) suffering of atrial fibrillation (n = 11), atrial flutter (n = 7), atrial paroxysmal tachycardia (n = 3), or sinus tachycardia (n = 1) were studied, having coronary artery disease (n = 8), dilative cardiomyopathy (n = 5), or no underlying diseases (n = 9). All groups went under catheter ablation (same protocol, duration: 35 +/- 10.3 mins; rate before ablation, 100-170/min in every case; after ablation, 70-80/min in Groups I and II and 70-90/min in Group III). A pacemaker (PM) was implanted 2 months before ablation in Group I (n = 9) and during ablation in Group II (n = 7). No PM was implanted in Group III (n = 6). A control group (n = 13; 7 men; mean age, 66.15 +/- 6.7 years) with sinus rhythm got a PM without ST and ablation. Blood samples were collected from the cubital vein immediately before (control), and 5 mins and 24 hrs after ablation. Plasma ET-1 and big ET-1 levels were measured after immunoprecipitation with Western blot analysis. There were no differences between plasma ET-1 levels in the ST groups and the control group (Groups I, II, and III vs. control group: 0.66 +/- 0.04 fmol/ml, 0.93 +/- 0.12 fmol/ml, and 0.68 +/- 0.05 fmol/ml vs. 0.50 +/- 0.05 fmol/ml, respectively; P < 0.05). Comparing the control, 5-min, and 24-hr samples, ET-1 levels decreased significantly after supraventricular tachycardia ablation in Groups I and III (control vs. Group I, 5 mins and 24 hrs: 0.66 +/- 0.04 fmol/ml vs. 0.50 +/- 0.04 fmol/ml and 0.29 +/- 0.05 fmol/ml; control vs. Group III, 24 hrs: 0.68 +/- 0.05 vs. 0.34 +/- 0.05 fmol/ml; P < 0.05). No plasma big ET-1 changes were measured in any of the groups. The rapid decrease of ET levels after catheter ablation suggests that a high ventricular rate can be a trigger of ET production. PM implantation procedure seems to interfere with the ET decrease in ST patients.

Aged↗

PubMed2004

Parasympathetic cardiac nerve stimulation with implanted coronary sinus lead.

A patient with drug-refractory paroxysmal atrial fibrillation associated with rapid ventricular rate underwent biatrial pacemaker implantation. During elective replacement of the pacemaker, a significant voltage- and frequency-dependent decrease in ventricular rate was achieved by high-frequency electrical stimulation (17 Hz) of parasympathetic cardiac nerves innervating the AV node with the implanted bipolar coronary sinus electrode. The negative dromotropic effect of parasympathetic stimulation was eliminated by intravenous administration of 1-mg atropine.

Anti-Arrhythmia Agents↗

PubMed2004

Effect of incessant ventricular tachyarrhythmias on serum endothelin and big-endothelin levels.

Endothelin-1 (ET-1) is a potent endogenous arrhythmogenic substance. The aim of our study was to investigate the changes of serum ET-1 and big-endothelin levels in patients suffering from spontaneous, incessant ventricular tachyarrhythmias. The 11 consecutive patients' (mean age, 59 +/- 11 years) underlying diseases were ischemic heart disease, valvular heart disease, dilated cardiomyopathy, primary electrical disease, and arrhythmogenic right ventricular dysplasia in five cases, three cases, one case, one case, and one case, respectively. The mean ejection fraction was 39 +/- 14%, New York Heart Association functional status was I, II, and III in two cases, four cases, and five cases, respectively. Ventricular tachycardias (VT) were detected in five patients, ventricular fibrillation (VF) in three patients, and VT + VF in three patients. VTs terminated spontaneously in two cases. Six patients required multiple external cardioversion/defibrillation shocks, while implantable cardioverter defibrillators terminated all sustained arrhythmias successfully in four cases. Blood samples were collected during arrhythmias and 24 hours (control) following the last VT/VF episode. Serum ET-1 and big-endothelin levels were measured with western blot analysis after immunoprecipitation. Serum ET-1 and big-endothelin levels were significantly higher during the last VT/VF compared with the control period (ET-1, 65.8 +/- 26.8 fmol/mL versus 53.9 +/- 22.3 fmol/mL, P < 0.05; big-endothelin, 115.2 +/- 39.3 fmol/mL versus 89.2 +/- 25.1 fmol/mL, P < 0.05). There was a negative correlation between the age and big-endothelin level measured at both times (during VT/VF, r = 0.94, P < 0.05; control, r = 0.91, P < 0.05). In conclusion, serum big-endothelin and ET-1 levels were significantly higher during incessant VT/VF, which can be a cause of multiple arrhythmia recurrence.

Adult↗

PubMed2004

Magnetic resonance imaging-based biventricular pacemaker upgrade.

This report describes a patient with drug refractory severe chronic ischemic heart failure, atrial fibrillation with bradycardia, and left bundle branch block who had a failed implantation of a biventricular pacemaker because of a high left ventricular pacing threshold. VVI pacemaker implantation had not improved the patient's condition. MRI-guided biventricular pacemaker upgrade had been performed with a left ventricular epicardial lead at the lateral region where a 4-mm thickening during systole had been proven. After 6 months of effective resynchronization, the patient's functional class improved to NYHA II without further need of hospitalization.

Atrial Fibrillation↗

PubMed2004

Changes of endothelin-1 and big endothelin-1 levels and action potential duration during myocardial ischemia-reperfusion in dogs with and without ventricular fibrillation.

Myocardial ischemia-reperfusion is associated with increased production of endothelin-1 (ET-1). Moreover, exogenous ET-1 has arrhythmogenic properties. Our aim was to investigate the correlation between endogenous ET-1, big ET-1 levels and epicardial monophasic action potential duration during myocardial ischemia-reperfusion in anesthetized dogs. Thirty-minute myocardial ischemia was followed by a 90-minute reperfusion period in 18 mongrel dogs. The total incidence of ventricular fibrillation (VF) during ischemia and reperfusion was 11.1% and 33.3%, respectively. During ischemia, the monophasic action potential duration at 90% repolarization (MAPD90) decreased significantly (control versus ischemia, 30 minutes, 224.7 +/- 7.1 ms versus 173.8 +/- 7.6 ms; P < 0.05), while during reperfusion a significant prolongation of MAPD90 was observed (ischemia, 30 minutes versus reperfusion, 30 minutes, 173.8 +/- 7.6 ms versus 249.7 +/- 9.9 ms, P < 0.05). During reperfusion ET-1 and big ET-1 levels increased significantly in the coronary sinus and femoral artery (control versus reperfusion, 90 minutes: coronary sinus ET-1, 15.1 +/- 1.4 fmol/mL versus 22.3 +/- 1.1 fmol/mL; big ET-1, 14.7 +/- 1.9 fmol/mL versus 27.4 +/- 2.3 fmol/mL; P < 0.05). The ET-1 concentration increased to a higher level during ischemia in dogs with VF compared with dogs surviving ischemia-reperfusion (non-VF versus VF: control, 15.1 +/- 1.3 versus 15.2 +/- 1.3; ischemia, 30 minutes, 17.6 +/- 1.2 fmol/mL versus 22 +/- 1.6 fmol/mL; P < 0.05), demonstrating a trend of correlation between endothelin levels and development of VF (P = 0.07). ET-1 and big ET-1 levels increased during reperfusion and in the VF group during ischemia; however, there was no correlation between endothelin levels and MAPD90.

Action Potentials↗

PubMed2002

Effects of implantable cardioverter defibrillator implantation and shock application on serum endothelin-1 and big-endothelin levels.

The incidence of ventricular tachyarrhythmias in the early post-operative period following implantable cardioverter-defibrillator (ICD) implantation is relatively high compared with that in control periods. Since endothelin-1 (ET-1) has been proven to be an endogenous arrhythmogenic substance, we investigated the changes in serum ET-1 and big-ET levels in patients undergoing ICD implantation. Serum concentrations of ET-1 and big-ET were measured in 14 patients with various heart diseases before the operation, as well as 1 min and 1 h after the last shock therapy. Big-ET levels and the sum of ET-1 and big-ET levels were unchanged immediately after the operation, but had increased significantly by 1 h after implantation (before, 1.57+/-0.61 pmol/l; 1 min, 1.86+/-0.87 pmol/l; 1 h, 4.29+/-1.65 pmol/l for big-ET; before, 3.44+/-1.07 pmol/l; 1 min, 3.79+/-1.29 pmol/l; 1 h, 6.36+/-2.03 pmol/l for big-ET+ET-1). There was a significant correlation between left ventricular ejection fraction and big-ET level measured 1 h after the last shock delivery (r=-0.542, P<0.05). We conclude that the increased big-ET level observed 1 h after the last induction and shock therapy of ventricular fibrillation might have a pathophysiological role in the increased incidence of post-operative spontaneous ventricular arrhythmias.

Aged↗