Diurnal variation of 6beta-hydroxycortisol in cardiac patients

The 24-hour urinary excretion of 6-beta-hydroxycortisol (6beta-OHC) and the urinary ratio of 6beta- hydroxycortisol/cortisol (6beta-OHC/UFC) have been proposed as noninvasive probes for human cytochrome P450 3A4 isoform (CYP3A4). In this study, we evaluated within- and between-day variability of 6beta-OHC excretion and 6beta-OHC/UFC ratio in nine Caucasian men with cardiac disease. Each study participant was asked to collect 24-hour urine specimens during four consecutive days in five standardized time intervals. Concentrations of UFC and 6beta-OHC were determined by immunoassay and the high-performance liquid chromatographic (HPLC) method, respectively. The HPLC method was accurate and precise, as indicated by the recovery rate of 96.5-103.3 % and less than 5.2 % and 6.3 % of the coefficient of variation for within-run and between-run assay, respectively. In patients, diurnal variations in UFC and 6beta-OHC excretion were parallel. Consequently, 6beta-OHC/UFC ratio remained stable during the day. Both, 6beta-OHC excretion and 6beta-OHC/UFC ratio showed significant relationship between 24-hour value and values measured in corresponding collection periods with best correlations obtained from night interval (22.00-06.00, r = 0.86-0.91). These results indicated that urinary 6beta-OHC excretion and 6beta-OHC/UFC ratio measured in overnight/morning urine could precisely reflect 24-hour values even in severely ill patients. In addition, a simple and sensitive HPLC method was described for determination of 6beta-OHC in urine.

[The activation of haemostasis during radiofrequency catheter ablation]

The aim of the study was to investigate chosen haemostasis activation markers during electrophysiologic study (EPS) with consequent radiofrequency catheter ablation (RFA). Sixty-three patients were studied prospectively. Indications for EPS and RFA were supraventricular tachycardias with the arrhythmogenic substrate located in the right atrium. Blood samples were drawn 24 hours before the procedure (T -1), at the beginning of the procedure (T0), at the end of EPS (T1), 30 minutes after completion of RFA (T2), and 24 hours after the procedure (T3). To study coagulation, fibrinolytic and platelet activation were measured concentrations of thrombin-antithrombin III (TAT), D-dimers (DD), platelet count and parameters, and circulating platelet aggregates (CPAi). During the EPS and RFA, TAT levels increased from the baseline 5.03 +/- 2.53 microg/l (T -1) to 12.90 +/- 12.83 microg/l at T0 (p < 0.001) to 36.07 +/- 15.59 microg/l at T1 (p < 0.001) and decreased to 28.85 +/- 13.14 microg/l at T2 (p < 0.001). Levels of DD increased from 0.30 +/- 0.20 mg/l at T0 to 0.44 +/- 0.25 mg/l at T1 (p < 0.001) and to 0.87 +/- 0.74 mg/l at T2 (p < 0.001). The number of platelets was significantly decreased (-13.7%) before and during the procedure (T -1 vs. T3; p < 0.001). Marked platelet activation (CPAi 0.62 +/- 0.32) was observed before the procedure opposite to the physiological values (CPAi 1.0 +/- 0.1), without changes during the procedure (CPAi at T2 0.69 +/- 0.23). Our results confirmed activation of several haemostasis parameters during EPS and RFA, and support eligibility of the antithrombotic prevention in patients indicated for EPS and RFA.

[Syncope in ventricular tachycardia as a first clinical sign of patent ductus arteriosus in an adulthood]

The case-report describes a 48-year-old-female patient with the patent ductus arteriosus with the following structural changes leading to the malignant arrhythmias manifested as a syncope. The patient was treated by Amplatzer occluder and the implantation of the cardioverter-defibrillator. The authors discuss the patent ductus arteriosus, arrhythmias and sudden cardiac death in the patients with the congenital heart disease in an adulthood.

Influence of amiodarone on urinary excretion of 6beta-hydroxycortisol in humans

The present study was undertaken to evaluate the use of cortisol 6beta-hydroxylation in defining the effect of amiodarone on cytochrome CYP3A activity. To accomplish this goal, the in vivo activity of CYP3A was estimated by measuring the 24-hour urinary excretion of 6beta-hydroxycortisol (6beta-OHC) and by calculating 24-hour ratio of 6beta-hydroxycortisol to urinary free cortisol (6beta-OHC/UFC ratio). Nine cardiac patients scheduled for amiodarone treatment were recruited to participate in this study. Urine was collected over a 24-hour period from each subject before the first amiodarone administration and during the third day of oral administration of amiodarone (200 mg four times daily as a loading dose). Three days of amiodarone treatment caused a significant decrease (p<0.05) in both the 6beta-OHC/UFC ratio and the 24-hour urinary excretion of 6beta3-OHC. These results suggest that amiodarone is an inhibitor of CYP3A activity.

Influence of CYP3A metabolizer status on the pharmacokinetics and pharmacodynamics of amiodarone

The present work was designed to determine whether the individual differences in pharmacokinetics and pharmacodynamics of amiodarone and its N-desethyl metabolite are related to cytochrome CYP3A metabolizer status.

METHODS

12 cardiac patients with inducible ventricular tachyarrhythmias during the baseline electrophysiologic study were enrolled in this study. Urinary 24-hour excretion of 6 beta-hydroxycortisol (6 beta-OHC and the ratio of 6 beta-hydroxycortisol to urinary free cortisol (6 beta-OHC/UFC) were measured before the first amiodarone administration. Trough plasma concentrations of amiodarone and N-desethylamiodarone (N-DEA) were measured after 79 +/- 11 days (2nd period) and after 182 +/- 25 days (3rd period). Electrophysiologic effects of amiodarone therapy were established with serial electrophysiologic studies in 9 of these patients at the baseline and after 79 +/- 11 days (during the second period).

RESULTS

Both the 6 beta-OHC excretion and 6 beta-OHC/UFC ratio varied approximately 6-fold between the patients. We found significant inverse correlation between the 6 beta-OHC excretion and the trough plasma concentrations of amiodarone at the time of the 3rd period (rs = -0.58, p < 0.05). Similarly, there was correlation between the 24-hour urinary 6 beta-OHC excretion and trough plasma concentrations of amiodarone during the 3rd period (rs = -0.64, p < 0.025). We were unable to detect any association between CYP3A activity and amiodarone pharmacodynamics.

CONCLUSION

This study points toward important information value of CYP3A metabolizer status in the context of therapeutic drug monitoring of amiodarone.

[Ventricular fibrillation in chronic heart disease]

The objective of the work was to describe in subjects with spontaneous ventricular fibrillation, after elimination of acute cardiac disease, the strategy of antiarrhythmic treatment and to evaluate, based on prospective follow-up, the effectiveness of this treatment. The authors included in the group 36 patients (30 men and 6 women) within the range from 34 to 78 years (mean age 58 +/- 11 years) with spontaneous ventricular fibrillation. They divided the group into a subgroup (15 subjects) without revascularization of the heart muscle, into a subgroup (17 subjects) with revascularization of the myocardium (coronary angioplasty and bypasses) and a subgroup (4 subjects) where ischaemic heart disease was ruled out (mostly cardiomyopathies). In all subgroups they used programmed ventricular stimulation (apparatuses of Quinton Co. USA, Biotronik Co. GFR), in the subgroup with revascularization within 3 months. During the diagnostic procedure of ventricular stimulation they tested antiarrhythmic drugs most frequently amiodarone per os (for 4 weeks). An implantable cardioverter--defibrillator was implanted in 17 patients (8 subjects without revascularization, 6 subjects with revascularization, 3 subjects without ischaemic heart disease). All patients were followed up till death, maximum 24 months. The authors evaluated the rate of cardiac deaths (death on cardiac grounds, incl. sudden arrhythmic death) and sudden arrhythmic deaths (within one hour after the onset of symptoms or the first malignant ventricular tachyarrhythmia recorded after implantation of the defibrillator). In the subgroup without revascularization with electric instability of the ventricles according to programmed stimulation 66.7% they described seven cardiac deaths (46.7%) and 6 sudden "arrhythmic" deaths (40%) incl. 5 subjects with ineffective testing of antiarrhythmic drugs. Conversely in the subgroup with revascularization and with diagnostic programmed stimulation in 47.1% they found 3 cardiac deaths (17.7%), one sudden "arrhythmic" death (5.9%)--a subject with ineffective testing. In the subgroup without ischaemic heart disease they recorded cardiac and sudden "arrhythmic" deaths in half the subjects, in all instances in subjects without inducible ventricular tachyarrhythmia. The authors found in the course of a two-year investigation a relapse of cardiac arrest in 25% of subjects after spontaneous ventricular fibrillation. A third of these subjects (all without a cardioverter-defibrillator) died. They confirm the benefit of implantation of a defibrillator for all subjects regardless of the basic diagnosis and revascularization of the heart muscle.

[Myocardial revascularization in malignant ventricular tachyarrhythmia--prognostic significance]

BACKGROUND

The survival of patients with chronic ischaemic heart disease and malignant ventricular tachyarrhythmia is influenced positively in some instances by revascularization of the heart muscle and implantation of a cardioverter-defibrillator. The objective of the submitted work was to evaluate by perspective follow-up of subjects with chronic ischaemic heart disease and malignant ventricular tachyarrhythmia: a) the effect of revascularization of the heart muscle on the prognosis, making use of programmed stimulation of the ventricles and testing the effectiveness of antiarrhythmic treatment; b) the importance of implantation of a cardioverter-defibrillator in revascularized and non-revascularized subjects for the prevention of sudden "arrhythmic" deaths.

METHODS AND RESULTS

The authors examined 37 patients (32 men and 5 women), age bracket 34 to 78 years (mean age 61 +/- 11) with IHD and spontaneous ventricular tachyarrhythmia after ruling out acute myocardial infarction. The group was divided into sub-groups without revascularization (21 subjects) and with revascularization (16 subjects). In both sub-groups programmed stimulation of the ventricles was implemented. During the diagnostic finding of programmed stimulation they tested antiarrhythmic drugs, most frequently amiodarone administered orally. A cardioverter-defibrillator was implanted to 10 patients. All patients were followed-up to death, the longest period being 24 months. They evaluated the frequency of cardiac deaths (death on cardiac grounds incl. sudden "arrhythmic" death) and sudden "arrhythmic" deaths (death within on hour after onset of symptoms or first recorded malignant ventricular tachyarrhythmia). In the sub-group without revascularization with diagnostic inducibility of the heart muscle in 85.7% of patients the authors described 9 cardiac deaths (42.9%) and 8 sden "arrhythmic" deaths (38.1%). Conversely in the sub-group with revascularization and with diagnostic programmed stimulation of the ventricles in half the subjects 5 clinical deaths were found (31.3%) and 3 sudden "arrhythmic" deaths (18.8%). Analysis of 11 sudden "arrhythmic" deaths revealed that no subjects with an implanted cardioverter-defibrillator (5) died (documented malignant ventricular tachyarrhythmia). Five of the six patients who died (all without a cardioverter-defibrillator) were not revascularized.

CONCLUSIONS

Revascularization of the heart muscle in patients with ischaemic heart disease (after elimination of acute cardiac infarction) and malignant ventricular tachyarrhythmia reduces the risk of relapse of this arrhythmia. The benefit of implantation of a cardioverter-defibrillator was recorded in all subjects regardless of the revascularization of the heart muscle.

[Revascularization of the myocardium and electrical instability of the ventricles]

The objective of the investigation was to evaluate in patients with chronic ischaemic heart disease (IHD) and malignant ventricular tachyarrhythmia the asset of myocardial revascularization for improvemet of the electric instability of the ventricular myocardium and a subsequent outline of the tactics of antiarrhythmic treatment. The authors included in the group a total of 35 patients (30 men and 5 women), age 34-78 years (mean 61 +/- 11) with IHD (according to selective coronarography) with spontaneous ventricular fibrillation (18 sebjects) or persistent (above 30s) marked symptomatic ventricular tachycardia (17 subjects), after ruling out acute cardiac infarction. The group was divided into a subgroups of 16 subjects with revascularization of the heart muscle (coronary angioplasty, coronary bypass) and a subgroup (19 subjects) without revascularization of the hearth muscle. In both groups programmed stimulation of the cardiac chambers was implemented (PSSK) (apparatuses of Qinton Co. USA, Biotronik, GFR), in the subgroup after revascularization within three months. In case of a PSSK finding the authors tested antiarrhythmic drugs, most frequently amiodarone by the oral route (within one month). Treatment not causing permanent ventricular arrhythmia was considered effective. In the subgroup with revascularization the authors described diagnostic PSSK in 8 subject where testing of antiarrhythmics was made in 6 patients (an effective antiarrhythymic agent was found in one instance, i.e. in 16.7%). In the subgroup without revascularization diagnostic PSSK was implemented in 17 subject. Antiarrythmic drugs were tested in 16 patients (effective treatment in 12.5%--always amiodaroe by the oral route). Diagnostic ventricular tachyarrhythmia was found in patients with spontaneous ventricular tachycardia in all instances with revascularization and in 92.3% without revascularization. In patients with spontaneous ventricular fibrillation they proved diagnostic PSSK in 33.3% of the patients with revascularization and in 66.7% without revascularization. The relative number of implantation of cardioverter-defibrillators in group with and without revascularization was similar (25%, 26.3%). Revascularization of the heart muscle in patients with chronic IHD reduces markedly the electric instability of the ventricular heart muscle, in particular in case of spontaneou ventricular fibrillation. Selective coronarography and possibly revascularization of the heart muscle is esential in those patients. The tactics of antiarrhythymic treatment of revascularization of the heart muscle were not affected.