Lörincz I

Effects of sex hormones on ECG parameters and expression of cardiac ion channels in dogs

Aim:  The aim of the study was to examine the effects of testosterone and oestrogen on the ECG parameters and expression of cardiac ion channels in male and female dogs, and to compare the dofetilide‐induced lengthening of QTc interval in control, castrated and hormone‐treated animals.

Proarrhythmic Potential of Antimicrobial Agents

Several antiarrhythmic and non-cardiovascular drug therapies including antimicrobial agents have been implicated as the causes for QT interval prolongation, torsades de pointes (TdP) ventricular tachycardia and sudden cardiac death. Most of the drugs that have been associated with the lengthening of the QT interval or development of TdP can also block the rapidly activating component of the delayed rectifier potassium current (IKr) in the ventricular cardiomyocytes. This article presents a review of the current literature on the QT interval prolonging effect of antimicrobials based on the results of the in vitro, in vivo studies and case reports. Our observations were derived from currently available Medline database. As we found, the most frequently QT interval prolonging antimicrobials are erythromycin, clarithromycin, fluoroquinolones, halofantrine, and pentamidine. Almost every antimicrobial-associated QT interval prolongation occurs in patients with multiple risk factors of the following: drug interactions, female gender, advanced age, structural heart disease, genetic predisposition, and electrolyte abnormalities. In conclusion, physicians should avoid prescribing antimicrobials having QT prolonging potential for patients with multiple risk factors. Recognition and appropriate treatment of TdP are also indispensable.

The effect of sleep apnea on QT interval, QT dispersion, and arrhythmias.

QT interval (QT) and QT dispersion (QTd) are electrocardiograph (ECG) parameters for the evaluation of myocardial repolarization. The inhomogeneity of ventricular repolarization is associated with ventricular arrhythmias. An increased QT, QTd, and increased incidence of nocturnal cardiac rhythm disturbances have been described in patients with obstructive sleep apnea (OSA), while other investigators did not find a relationship between ventricular arrhythmias and OSA.

Temporary Pacing in Complete Heart Block due to Lyme Disease: A Case Report

The authors present the case of a 44‐year‐old man who was admitted with complete heart block and signs of severe bradycardio, After steroid administration and temporary pacemaker treatment the complete heart block resolved. During this therapy transient ST segment and T wave abnormalities occurred. The positive Borrelia burgdorferi antibody titer arrived only after therapy had been completed. This is regarded as the first case of Lyme carditis with complete heart block diagnosed in eastern Europe. Carditis resolved without antibiotic treatment and has not recurred.

Arterial stiffness in chronic renal failure and after renal transplantation.

Arterial stiffness is an independent cardiovascular risk factor, along with aging, hypertension, and cardiovascular disease. The augmentation index (AIx) and pulse wave velocity (PWV) are early markers of atherosclerotic vascular changes. Arteriography was used to determine systolic and diastolic blood pressure, pulse pressure (PP), AIx, and PWV in 82 male and 64 female renal transplant recipients (mean [SD] age, 45.3 [11.2] years). Cardiovascular risk was assessed using echocardiography and ultrasonography of the carotid arteries. The left ventricular wall thickness, ejection fraction, and stenosis of the carotid arteries were also measured. Fasting serum creatinine, cystatin C, homocysteine, C-reactive protein, immunoreactive parathyroid hormone, lipid, and calcium-phosphorus concentrations were determined. The serum cystatin concentration was 2.1 (0.2) mg/L, and the homocysteine concentration, 15.2 (2.6) micromol/L. After transplantation, body mass index, fat mass, and visceral fat area increased significantly (P < .01). The AIx was increased (AIx > or =10%) in 20% of men and 37% of women, PWV was increased (>10 m/s) in 43% of men and 34% of women, and PP was pathologically high (>12 m/s) in 10% of men and 12% of women. The PWV was significantly related to age (r = 0.52) and ventricular wall thickness (r = 0.46). Pulse pressure, BMI, and systolic and diastolic blood pressure correlated positively but modestly with PWV. There was a significant relationship between AIx80 and systolic (r = 0.42) and diastolic (r = 0.39) blood pressure and PP (r = 0.33). The ejection fraction correlated negatively with PWV and AIx. There was a strong association between carotid artery stenosis, PWV, and AIx80. All patients with PWV greater than 10 m/s demonstrated carotid artery stenosis. In conclusion, arteriography is an objective, noninvasive, and convenient method for early diagnosis and follow-up of atherosclerosis.

Motor vehicle accident with complete loss of consciousness due to vasovagal syncope

Vasovagal syncope (VVS) is one of the most common causes of complete or partial loss of consciousness, thus it might cause harm to the patients themselves or innocent bystanders while driving a car. In our case report we introduce the case of a 60-year-old man who was admitted to hospital after a serious motor vehicle accident due to loss of consciousness. We demonstrate the process and results of complete cardiologic and neurological assessment. Our case report illustrates the importance of recognition of patients with a high risk for incapacitating symptoms due to VVS, and the use of head-up tilt-table tests to determine the diagnosis and to guide therapy with beta-blocking agents. As transient loss of consciousness during driving may cause potentially fatal accident, it has to be taken into consideration during decision making for issue of driving licenses to patients with VVS.

Myocardial adrenergic innervation in patients with vasovagal syncope measured with 123I-MIBG uptake.

BackgroundData about biochemical abnormalities (catecholamines) during vasovagal syncope (VVS) are available, but adrenergic myocardial structural damage may be hypothesized as well. AimTo study the global and regional adrenergic myocardial innervations in patients with VVS that was shown by head-up tilt table testing. Patients and methodsFifteen adult patients with VVS were studied. The age of patients was 44±18 years (17–73), nine were female and six were male. According to the tilt test results, five patients had cardioinhibition, six patients had vasodepressor syncope and four patients suffered from mixed-type VVS. Ischemic heart diseases were excluded by normal 99mTc-MIBI rest–stress dipyridamol single-photon emission computed tomography (SPECT) results. A control group was formed from six healthy adult volunteers. To investigate cardiac sympathetic innervations 250–370 MBq iodine-123 meta-iodobenzylguanidine (123I-MIBG) was used. Fifteen minutes after the intravenous administration of 123I-MIBG early, and 2–3 h later, delayed planar myocardial and tomographic (SPECT) scintigraphies were performed. The heart-to-mediastinum count ratio (H/M) was calculated for both early and delayed images, together with the decay-corrected change rates. The regional 123I-MIBG uptake was visualized on SPECT slices and polar map images. The regional uptake was considered pathological below 50% compared with normal uptake sites. ResultsDelayed H/M ratios significantly depended on group (analysis of variance: P=0.005), whereas early H/M values did not. Although the decay-corrected myocardial MIBG uptake increased in time in controls, less wash-in or even wash-out could be observed in the VVS groups; however, difference from the controls was significant only in the vasodepressor group (Dunnetts t-test: P<0.05). All patients had regional 123I-MIBG uptake deficit in different regions. ConclusionIn our patients with VVS, global 123I-MIBG deficit was present frequently, and all patients had regional adrenergic nerve function deficit. These alterations may play a role in causing clinical symptoms and have importance in staging and treatment planning.

Atrial fibrillation and the autonomous nervous system

The autonomic nervous system has a crucial role in the genesis, maintenance and abruption of atrial fibrillation. The substrate and trigger mechanism of atrial fibrillation can be influenced by the changing autonomic tone. The authors summarize the current knowledge on the relationship between autonomic nervous system and atrial fibrillation. The special neuroanatomical status and the role of autonomic reflexes and baroreflex in the initiation, maintenance, and termination of arrhythmia are reviewed. Furthermore, the mechanism and consequences of autonomic effect of the curative radiofrequency catheter ablation of pulmonary vein with atrial vagal neuroablation are discussed. At the end we also summarize the pharmacologic therapy of atrial fibrillation. Classification of atrial fibrillation, as either vagal or adrenergic, has only limited impact on current management.

Végstádiumú vesebetegség és kamrai szívritmuszavarok. A hemodialízis és a hemodiafiltráció a kamrai repolarizációt eltéroen befolyásolja

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.

Sinus node dysfunction due to psychotropic agents' combination.

Background: Although sinus node dysfunction is primarily related to degenerative fibrosis of nodal tissue in the elderly, it may occur at any age secondary to other cardiac abnormalities or extrinsic causes. Pharmacologic agents including psychotropic drug therapy may also play a role. Method: We present the case of a 53-year-old woman with bipolar affective disorder in whom antipsychotic agents were suspected of inducing sinus node dysfunction. Result: The combination of psychotropic agents including lithium, quetiapine and carbamazepine (first occasion) or escitalopram (second occasion) has been implicated as a cause for sinus node dysfunction. Conclusion: Patients with severe mental illness usually require long-term psychotropic drug therapy, often in combination. This may enhance efficacy but also involves an increased risk of adverse effects including cardiotoxicity.