István Lőrincz

Effects of rosiglitazone on the configuration of action potentials and ion currents in canine ventricular cells

BACKGROUND AND PURPOSE In spite of its widespread clinical application, there is little information on the cellular cardiac effects of the antidiabetic drug rosiglitazone in larger experimental animals. In the present study therefore concentration‐dependent effects of rosiglitazone on action potential morphology and the underlying ion currents were studied in dog hearts.

Hemodialysis and hemodiafiltration differently modulate left ventricular diastolic function

BackgroundRenal replacement therapy may have a favorable effect on diastolic left ventricular function, but it is not clear whether hemodiafiltration is superior to hemodialysis in this field. Nitric oxide (NO) and asymmetric dimethylarginine (ADMA) may play a role in the changes of intracardiac hemodynamics, but it is not clear whether the different renal replacement methods have disparate influence on the metabolism of these materials.MethodsThirty patients on renal replacement therapy were investigated. First, data was analyzed while patients received hemodiafiltration over a period of three months. Then, the same patients were evaluated during treatment with hemodialysis for at least another three months. Echocardiography was performed before and after renal replacement therapy.ResultsNo significant difference was found in the volume removals between hemodialysis and hemodiafiltration. The left atrial diameter and transmitral flow velocities (E/A) decreased significantly only during hemodiafiltration. A positive correlation was observed between the left atrial diameter and E/Ea representing the left ventricular pressure load during hemodiafiltration. Significant correlations between NO and A and E/A were observed only in the case of hemodiafiltration.ConclusionHemodiafiltration has a beneficial effect on echocardiographic markers representing left ventricular diastolic function. This could be attributed to the differences between the dynamics of volume removal and its distribution among liquid compartments.

The disparate effect of hemodialysis and hemodiafiltration on T-wave-peak-to-end interval (Tpe) and Tpe/QT ratio of the surface electrocardiogram

Aim: The prolongation of T-wave-peak-to-end interval (Tpe) and arrhythmogenic index (AIX) could predict arrhythmias. Developing of ventricular arrhythmias is increased during hemodialysis (HD), but the effects of hemodiafiltration (HDF) on ventricular repolarization have not been elucidated yet. Methods: Thirty patients was investigated while they were receiving hemodiafiltration over a period of three months then the same group of patients was evaluated during treatment with hemodialysis for at least another three months. Ionic parameters, surface electrocardiograms (ECG), echocardiography, Holter ECGs were performed. Results: T-wave-peak-to-end interval and arrhythmogenic index significantly increased at the 240th minute of hemodialysis while did not change during hemodiafiltration. No malignant ventricular arrhythmias occurred, but number of ventricular premature beats was significantly higher during hemodialysis as compared to those during hemodiafiltration. Regarding hemodialysis a significant relationship was observed between the ratio of ventricular premature beats and arrhythmogenic index. Left ventricular mass index, septal-, posterior wall, inferior vena cava, left atrial diameters showed a positive correlation with T-wave-peakto-end interval only in the case of hemodialysis. A negative correlation occurred between the left ventricular ejection fraction, T-wave-peak-to-end interval and arrhythmogenic index, moreover between serum sodium and T-wave-peak-to-end interval, arrhythmogenic index during hemodialysis. Conclusions: Our results suggest that hemodialysis has unfavourable effect on the studied ECG parameters compared to hemodiafiltration. Correspondence to: Zoltan Szabo, Institute of Medicine University of Debrecen Clinical Centre, Faculty of Medicine, Nagyerdei krt. 98. 4032 Debrecen, Hungary, Tel: (36)-52-413 653; E-mail: szaboz.med@gmail.com

Végstádiumú vesebetegség és kamrai szívritmuszavarok. A hemodialízis és a hemodiafiltráció a kamrai repolarizációt eltérően befolyásolja @@@End stage renal disease and ventricular arrhythmia. Hemodialysis and hemodiafiltration differently affect ventricular repolarization

Various factors (hypertension [27%], diabetes mellitus [40%]) and their cardiovascular complications play an important role in the genesis of end stage renal disease. Furthermore, primary kidney diseases (glomerulonephritis, tubulointerstitial nephritis, obstructive uropathy, analgesic nephropathy, polycystic kidney disease, autoimmune diseases) have an unfavorable effect on the cardiovascular outcome of this particular population. Increased susceptibility for arrhythmias may be caused by intermittent volume overload, metabolic disturbance, renal anemia, structural and electrophysiological changes of the myocardium, inflammatory mechanisms that may worsen the mortality statistics of these patients. A novel renal replacement method, hemodiafiltration - based on a convective transport - ensures reduced mortality that may be attributed to a decreased occurrence of arrhythmias. The aim of this paper is to review the pathogenetic factors taking part in the arrhythmogenesis of end stage renal disease and to provide diagnostic and therapeutic opportunities that can help in the prediction and prevention of arrhythmias.

End stage renal disease and ventricular arrhythmia. Hemodialysis and hemodiafiltration differently affect ventricular repolarization

Various factors (hypertension [27%], diabetes mellitus [40%]) and their cardiovascular complications play an important role in the genesis of end stage renal disease. Furthermore, primary kidney diseases (glomerulonephritis, tubulointerstitial nephritis, obstructive uropathy, analgesic nephropathy, polycystic kidney disease, autoimmune diseases) have an unfavorable effect on the cardiovascular outcome of this particular population. Increased susceptibility for arrhythmias may be caused by intermittent volume overload, metabolic disturbance, renal anemia, structural and electrophysiological changes of the myocardium, inflammatory mechanisms that may worsen the mortality statistics of these patients. A novel renal replacement method, hemodiafiltration - based on a convective transport - ensures reduced mortality that may be attributed to a decreased occurrence of arrhythmias. The aim of this paper is to review the pathogenetic factors taking part in the arrhythmogenesis of end stage renal disease and to provide diagnostic and therapeutic opportunities that can help in the prediction and prevention of arrhythmias.

Molecular and genetic background of sudden cardiac death

Despite recent findings on the functional, structural and genetic background of sudden cardiac death, the incidence is still relatively high in the entire population. A thorough knowledge on susceptibility, as well as pathophysiology behind the development of malignant arrhythmias will help us to identify individuals at risk and prevent sudden cardiac death. This article presents a review of the current literature on the role of altered intracellular Ca2+ handling, acute myocardial ischaemia, cardiac autonomic innervation, renin-angiotensin-aldosterone system, monogenic and complex heritability in the pathogenesis of sudden cardiac death.

Arrhythmias in patients with obstructive sleep apnea

The authors summarize the current knowledge on the types, prevalence, reasons, diagnosis and current therapy of arrhythmias occurring in patients with obstructive sleep apnea. Most of the patients with obstructive sleep apnea have nocturnal bradycardia (5-50%), paroxysmal tachyarrhythmia (atrial 35%; ventricular 0-15%), or both. The frequency of rhythm disturbances associated with the severity of the sleeping disorder. It is important to recognize the factors predisposing to arrhythmias and the early appropriate therapy of patients is essential, in order to protect patients from life threatening arrhythmias which may worsen the clinical outcome.