Search

Background Many drugs increase the duration of the QT interval of patients, potentially leading to harmful effects such as polymorphic ventricular arrhythmias. Most of these drugs do so by inhibiting the rapid component IKr of the delayed rectifier potassium current IK. Methadone is the most prescribed heroin maintenance treatment and is known to inhibit the cardiac potassium channel hERG, which recapitulates IKr. In order to evaluate if any polymorphism of potassium channels’ genes could explain some of the “idiosyncratic” QT prolongations observed in patients treated with methadone, we tested the association between KCNE1 , KCNE2 , and KCNH2 polymorphism and the QT interval prolongation in those patients, controlling for other variables associated with a decrease of the repolarizing reserve. Methods A cohort of 82 patients treated with stable dosage of methadone (mean dosage 65 mg/d) for at least three months was genotyped for five polymorphisms in KCNE1 , KCNE2 and KCNH2 genes and had their corrected QT (QTc) assessed. Results The mean QTc interval was 415 ± 34 ms. In a linear regression model, longer QTc interval was associated with methadone dosage and with one genetic factor. Each copy of a Lys allele at codon 897 of KCNH2 , the gene that encodes the cardiac potassium voltage-gated channel hERG, was associated with a 15.4 ms longer QTc (95% CI [4.6–26.2]; p = 0.001). Conclusion KCNH2 genotyping may be relevant in the analysis of cumulative risk factors for QT prolongation in patients on methadone maintenance treatment.

Drug-induced adverse events have been accessible to patient's spontaneous reporting in France and such notifications have been steadily increasing since 2011. However, these notifications are still shrouded with medical perplexity and are sometimes subjected to partial caution in their interpretation by the patient's physician. We aimed to evaluate and compare prospectively the relevance of such spontaneous notifications with those provided by healthcare professionals to the French Pharmacovigilance Center of Nice-Alpes-Côte d'Azur.Spontaneous reporting of drug adverse events notified by patients and health care professionals were compared in terms of critical (name, date, effect, drug involved, chronological compatibility) and non-critical (posology, dosage) information, whereas the plausibility of the cases were assessed in weekly multispecialty staffs. Each patient's notification was matched with the immediate pre- and post-notifications declared by health care providers.Spontaneous notifications from 61 patients were compared with 122 notifications from health care providers. Neither the critical information necessary for declaring the case in the national database (7/61 versus 16/122, P=0.75), nor the uncritical elements allowing to assess the case (30/61 versus 51/122, P=0.22), its plausibility or the causality of the drug (P=0.10) differed significantly between the two groups. 107 cases out of 122 (88%) notified by health care providers were classified as serious, as compared with 19 out of 61 (15%) of patient's ones (P0.001).Despite concerns from pharmacovigilance specialists in France, the medical relevance of spontaneous reported drug-associated adverse events does not differ from that of health care providers.

The incidence of suicide attempts (fatal and non-fatal) was analysed in a prospective cohort of patients with schizophrenia randomly assigned to sertindole (4905 patients) or risperidone (4904 patients) in a parallel-group open-label study with blinded classification of outcomes (the sertindole cohort prospective study--SCoP). The total exposure was 6978 and 7975 patient-years in the sertindole and risperidone groups, respectively. Suicide mortality in the study was low (0.21 and 0.28 per 100 patients per year with sertindole and risperidone, respectively). The majority (84%) of suicide attempts occurred within the first year of treatment. Cox's proportional hazards model analysis of the time to the first suicide attempt, reported by treating psychiatrists and blindly reviewed by an independent expert group according to the Columbia Classification Algorithm of Suicide Assessment (both defining suicide attempts by association of suicidal act and intent to die), showed a lower risk of suicide attempt for sertindole-treated patients than for risperidone-treated patients. The effect was statistically significant with both evaluation methods during the first year of randomized treatment (hazard ratios [95% CI]: 0.5 [0.31-0.82], p=0.006; and 0.57 [0.35-0.92], p=0.02, respectively). With classification by an independent safety committee using a broader definition including all incidences of intentional self-harm, also those without clear suicidal intent, the results were not significant. A history of previous suicide attempts was significantly associated with attempted suicides in both treatment groups.

Thomas SHL, Drici MD, Hall GC, Crocq MA, Everitt B, Lader MH, Le Jeunne C, Naber D, Priori S, Sturkenboom M, Thibaut F, Peuskens J, Mittoux A, Tanghoj P, Toumi M, Moore ND, Mann RD. Safety of sertindole versus risperidone in schizophrenia: principal results of the sertindole cohort prospective study (SCoP) Objective: To explore whether sertindole increases all-cause mortality or cardiac events requiring hospitalization, compared with risperidone. Method: Multinational randomized, open-label, parallel-group study, with blinded classification of outcomes, in 9858 patients with schizophrenia. Results: After 14147 person-years, there was no effect of treatment on overall mortality (sertindole 64, risperidone 61 deaths, Hazard Ratio (HR) = 1.12 (90% CI: 0.83, 1.50)) or cardiac events requiring hospitalization [sertindole 10, risperidone 6, HR = 1.73 (95% CI: 0.63, 4.78)]: Of these, four were considered arrhythmia-related (three sertindole, one risperidone). Cardiac mortality was higher with sertindole (Independent Safety Committee (ISC): 31 vs. 12, HR=2.84 (95% CI: 1.45, 5.55), P = 0.0022; Investigators 17 vs. 8, HR=2.13 (95% CI: 0.91, 4.98), P = 0.081). There was no significant difference in completed suicide, but fewer sertindole recipients attempted suicide (ISC: 68 vs. 78, HR=0.93 (95% CI: 0.66, 1.29), P = 0.65; Investigators: 43 vs. 65, HR=0.67 (95% CI: 0.45, 0.99), P = 0.044). Conclusion: Sertindole did not increase all-cause mortality, but cardiac mortality was higher and suicide attempts may be lower with sertindole.

Il existe en France plus de 100 associations fixes medicamenteuses (princeps et generiques) a disposition des praticiens pour traiter les patients hypertendus. Un tel foisonnement peut laisser perplexe. Neanmoins, plusieurs arguments peuvent en expliquer la cause : le traitement doit avoir un impact incisif et rapide sur les chiffres tensionnels et entrainer un minimum d’effets indesirables. Deux antihypertenseurs coadministres sont plus efficaces, souvent mieux toleres et ont fait la preuve dans les essais cliniques, de leur superiorite aux monotherapies. Le fait de les administrer en une seule prise facilite l’observance de patients souvent asymptomatiques. Les classes d’antihypertenseurs que l’on peut associer sont nombreuses ainsi que les specialites au sein de ces classes et leurs differents dosages (deux a trois par association). Aussi, les industriels du medicament ne s’y sont pas trompes : pour un prix de remboursement des associations fixes tres proche des monotherapies dont ils disposent, ils peuvent proposer un eventail plus large de medicaments, plus efficaces, sans perdre de parts de marche face a une concurrence rude. Les generiques de certaines associations qui apparaissent sur le marche ne sont que la rancon, a echeance de leur brevet, du succes des associations de princeps.

Atypical antipsychotics are the treatment of choice for patients with schizophrenia. They are generally better tolerated than conventional antipsychotics since most do not cause debilitating extrapyramidal symptoms. They are associated though with an array of cardiovascular adverse events that may affect morbid-mortality of schizophrenic patients. Orthostatic hypotension, electrocardiographic changes and metabolic syndrome (MS) are the main cardiovascular effects of atypical antipsychotics. They contribute to the overall disease burden associated with schizophrenia even though the benefit risk of such treatments still is highly favourable. We aim to review the main cardiovascular side effects of new atypical oral antipsychotics, the pharmacological mechanisms involved, and to which drugs they are particularly attributed. Copyright © 2007 John Wiley & Sons, Ltd.

Introduction: no routine monitoring is deemed necessary with direct oral anticoagulants dabigatran (D) and rivaroxaban(R). Yet, their misuse may lead to inefficacy or increased risk of bleeding. Hypothesis: due to the prevalence of elderly patients in our medical center, the pharmacology department was asked to measure R and D plasma concentrations. Therefore we aimed not only to check their prescription adequacy but also to evaluate whether bleeding or thrombosis adverse events were associated with drug concentrations clearly outside of their expected “normal” range. Methods: Patients receiving R or D for either AFib, deep venous thrombosis or its prevention were included and had blood samples drawn for drug measurements, by HPLC-tandem mass spectrometry. Adequacy of the patient prescription was checked by pharmacists according D & R respective SmPCs. A robust and conservative method was applied to evaluate anticoagulant concentrations : D & R concentrations were blindly deemed “normal” when within the [IC] 95 limits (peak and trough, relative to the dose) observed in the respective RE-LY and Rocket-AF pivotal studies, as compared to “out of range” when outside of these limits. Results: 287 consecutive patients from our center had their concentration of R (n=219 : 76%) or D (n = 68 : 24%) measured. The inadequacy of the prescriptions was 31.4% alltogether. Seventy patients presented with bleeding (n = 48, 17%) or thrombosis (n = 22, 8%), that either led to their admission in emergency, or occurred in the hospital wards. Bleedings and thrombosis were significantly associated with out-of-range concentrations (p-1 and D: 128 VS 80 μg.l -1 ) whereas thrombosis were associated with lower ones (R: 75 VS 106 μg.l -1 D: 29 VS 93 μg.l -1 ). HAS-BLED Score was 2.0 ± 0.9 for bleeding cases as compared to 1.5 ± 0.9 (p Conclusions: therapeutic drug monitoring of direct oral anticoagulants might not be superfluous, at least for R & D, especially in patients with a higher score HAS-BLED.

Idarucizumab administration for reversing dabigatran effect in an acute kidney injured patient with bleeding

Acetylcholine (ACh) is an important neuromodulator of cardiac function that is released upon stimulation of the vagus nerve. Despite numerous reports on activation of IKACh by acetylcholine in cardiomyocytes, it has yet to be demonstrated what role this channel plays in cardiac conduction. We studied the effect of tertiapin, a bee venom peptide blocking IKACh, to evaluate the role of IKACh in Langendorff preparations challenged with ACh. ACh (0.5 μM) reproducibly and reversibly induced complete atrioventricular (AV) blocks in retroperfused guinea-pig isolated hearts (n=12). Tertiapin (10 to 300 nM) dose-dependently and reversibly prevented the AV conduction decrements and the complete blocks in unpaced hearts (n=8, P

The authors report in detail the case of a 27-year-old man who experienced sudden cardiac death 2 days after coprescription of the neuroleptic pimozide and the macrolide antibiotic clarithromycin after the documentation of a prolonged QT interval. To determine the prevalence of this interaction, the authors referred to the Spontaneous Reporting System of the Food and Drug Administration and identified one similar case in which clarithromycin was coprescribed with pimozide and sudden cardiac death occurred shortly thereafter. In addition, the search identified 39 cases of cardiac arrhythmia associated with pimozide, 11 with pimozide alone, and 6 with clarithromycin alone, 1 of which had a positive rechallenge. The mechanism of the interaction between clarithromycin and pimozide seems to involve the inhibition of the hepatic metabolism of pimozide by the macrolide. The authors demonstrated that clarithromycin is able to inhibit the metabolism of pimozide in human liver microsomal preparations (K(i) = 7.65 +/- 1.18 microM) and that pimozide, but not clarithromycin or its primary metabolite, is able to prolong the electrocardiac QT interval in a dose-dependent manner in the isolated perfused rabbit heart. The increase was 9.6 +/- 1.1% in male hearts (N = 5) and 13.4 +/- 1.2% in female hearts (N = 4) (p < 0.05).

1. In the present study, two new peptides, phrixotoxins PaTx1 and PaTx2 (29-31 amino acids), which potently block A-type potassium currents, have been purified from the venom of the tarantula Phrixotrichus auratus. 2. Phrixotoxins specifically block Kv4.3 and Kv4.2 currents that underlie I(to1), with an 5 < IC50 < 70 nM, by altering the gating properties of these channels. 3. Neither are the Shaker (Kv1), Shab (Kv2) and Shaw (Kv3) subfamilies of currents, nor HERG, KvLQT1/IsK, inhibited by phrixotoxins which appear specific of the Shal (Kv4) subfamily of currents and also block I(to1) in isolated murine cardiomyocytes. 4. In order to evaluate the physiological consequences of the Ito1 inhibition, mice were injected intravenously with PaTx1, which resulted in numerous transient cardiac adverse reactions including the occurrence of premature ventricular beats, ventricular tachycardia and different degrees of atrioventricular block. 5. The analysis of the mouse electrocardiogram showed a dose-dependent prolongation of the QT interval, chosen as a surrogate marker for their ventricular repolarization, from 249 +/- 11 to 265 +/- 8 ms (P < 0.05). 6. It was concluded that phrixotoxins, are new and specific blockers of Kv4.3 and Kv4.2 potassium currents, and hence of I(to1) that will enable further studies of Kv4.2 and Kv4.3 channel and/or I(to1) expression.

Some antipsychotic drugs have been found to prolong the QT interval on electrocardiographic (ECG) recordings, a phenomenon which, when severe, may facilitate the occurrence of complex ventricular arrhythmias such as torsade de pointes. However, the effects of these drugs on the cardiac repolarization process have not been evaluated extensively. This study was designed to examine the potency of five antipsychotic drugs in lengthening the QT interval of the perfused feline heart: haloperidol, risperidone, sertindole, clozapine, and olanzapine. The hearts were infused with increasing concentrations of drugs (0.1-20 micromol/L) for 40-minute intervals at each concentration. ECG recordings were made, with signals amplified and data recorded on a strip chart recorder. Four representative beats from each set of three signal recordings were chosen for QT interval measurement. Our data indicated that all tested drugs prolonged the QT interval in a concentration-dependent manner (p < 0.01). Haloperidol and risperidone were significantly more potent than sertindole, clozapine, and olanzapine (p < 0.001). At a concentration of 0.5 micromol/L over a 40-minute infusion interval, haloperidol lengthened the interval by 26.2+/-0.7%, risperidone by 19.4+/-2.2%, and sertindole by 8.9+/-3.5% (p < 0.05 compared with baseline); clozapine and olanzapine were less potent. Although species differences may limit extrapolation of our findings to humans, the cardiac potassium channels of felines clearly resemble those of humans. This model may serve as the basis for further studies of drug-induced prolongation of the QT interval and precipitation of ventricular arrhythmias.

SummaryBackgroundNational population-based management and outcome data for patients of all ages hospitalized for heart failure have rarely been reported.AimNational population-based management and outcome of patients of all ages hospitalized for heart failure have rarely been reported. The present study reports these results, based on 77% of the French population, for patients hospitalized for the first time for heart failure in 2009.MethodsThe study population comprised French national health insurance general scheme beneficiaries hospitalized in 2009 with a principal diagnosis of heart failure, after exclusion of those hospitalized for heart failure between 2006 and 2008 or with a chronic disease status for heart failure. Data were collected from the national health insurance information system (SNIIRAM).ResultsA total of 69,958 patients (mean age, 78 years; 48% men) were studied. The hospital mortality rate was 6.4%, with 1-month, 1-year and 2-year survival rates of 89%, 71% and 60%, respectively. Heart failure and all-cause readmission-free rates were 55% and 43% at 1 year and 27% and 17% at 2 years, respectively. Compared with a reference sample of 600,000 subjects, the age- and sex-standardized relative risk of death was 29 (95% confidence interval [CI] 28–29) at 2 years, 82 (95% CI 72–94) in subjects aged

Background The incidence of heart failure (HF) is stable in industrialized countries, but its prevalence continues to increase, especially due to the ageing of the population, and mortality remains high. Objective To estimate the incidence in France and describe the management and short-term outcome of patients hospitalized for HF for the first time. Method The study population comprised French national health insurance general scheme beneficiaries (77% of the French population) hospitalized in 2009 with a principal diagnosis of HF after exclusion of those hospitalized for HF between 2006 and 2008 or with a chronic disease status for HF. Data were collected from the national health insurance information system (SNIIRAM). Results A total of 69,958 patients (mean age 78 years; 48% men) were included. The incidence of first hospitalization for HF was 0.14% (≥ 55 years, 0.5%; ≥ 90 years, 3.1%). Compared with controls without HF, patients more frequently presented cardiovascular or other co-morbidities. The hospital mortality rate was 6.4% and the mortality rate during the 30 days after discharge was 4.4% (3.4% without readmission). Among 30-day survivors, all-cause and HF 30-day readmission rates were 18% (

International audience; HIV-protease inhibitors (PIs) markedly decreased mortality of HIV-infected patients. However, their use has been associated with occurence of metabolic abnormalities the causes of which are not well understood. We report here that lopinavir, one of the most prescribed PI, dose-dependently co-induced insulin resistance and ER stress in human adipocytes obtained from differentiation of precursor cells. Insulin resistance was subsequent to IRS1 phosphorylation defects and resulted in a concentration-dependent decrease of glucose uptake. The major ER stress pathway involved was the phosphorylation of eIF2-alpha. Salubrinal, a selective eIF2-alpha dephosphorylation inhibitor, induced insulin resistance by targeting IRS1 phosphorylation at serine 312 and acted synergistically with LPV when both drugs were used in combination. This study points out the key role of eIF2-alpha phosphorylation in the development of PI-associated insulin resistance and ER stress. Thus, this protein represents a promising therapeutic target for development of new PIs devoid of adverse metabolic effects.

Sex Differences in Long QT-Induced Arrhythmias in Prepubertal Rabbits. Females have a greater susceptibility to Torsade de Pointes in congenital and drug-induced long QT syndrome (LQTS) that has been attributed to the modulation of ion channel expression by sex hormones. However, little is known regarding sex differences in pre-puberty, that is, before the surge of sexual hormones. In patients with congenital LQTS types 1 and 2, male children tend to have a greater occurrence of adverse events, especially in 10-15 year olds, than their female counterpart. To evaluate whether the rabbit model of drug-acquired LQTS exhibits similar age dependences, hearts of prepubertal rabbits were perfused, mapped optically to record action potentials (APs) and treated with an I K r blocker, E4031 to elicit LQTS2. As expected, AP durations (APD) were significantly longer in female (n = 18) than male hearts (n = 10), at long cycle length. Surprisingly, E4031 (50-250 nM) induced a greater prolongation of APDs in male than in female hearts, and in both genders reversed the direction of repolarization (apex → base to base → apex), enhancing dispersions of repolarization. Furthermore, in male hearts, E4031 (0.5 μM) elicited early afterdepolarizations (EADs) that progressed to polymorphic ventricular tachycardia (PVT) (n = 7/10) and were interrupted by isoproterenol (40 nM) and prevented by propranolol (0.5-2.5 μM). In female hearts, E4031 (0.5 μM) produced marked prolongations of APDs yet few EADs with no progression to PVT (n = 16/18). Thus, sex differences are opposite in prepubertal versus adult rabbits with respect to E4031-induced APD prolongation, EADs and PVT, underscoring the fact that APD prolongation alone is insufficient to predict arrhythmia susceptibility.

Background — Molecularly engineered mice are extensively used as models of cardiovascular diseases, yet little is known about sex differences in the electrophysiology of mouse hearts. Methods and Results — This study investigated the influence of sex on drug-induced polymorphic ventricular tachycardia (PVT) in Langendorff-perfused male and female mice hearts (n=54) by injecting a bolus of halothane (1.75 mmol/L) in the perfusate while recording ECGs or optical action potentials (APs). There were no statistically significant differences between male and female hearts (n=54) with respect to mean RR (193±5 ms), PR (47±1 ms), QT intervals (101±3 ms), optical AP durations (APD 75 =23.11±4.2 ms), dispersion of refractory periods, and conduction velocities (n=5 male and 5 female). Halothane induced PVTs lasting a mean duration of 90 seconds; in female hearts, 55% of PVTs lasted longer than the median, whereas in male hearts 17% exceeded the mean ( P P 75 (17.61±1.6 ms) and then elicited VTs (n=6 of 6), but in female hearts, halothane elicited PVTs (n=1 of 6) or arrested the hearts (n=5 of 6). Except for KCNE1, Northern blots (KCNQ1, MERG, Kv1.5, connexins 40 and 43, TREK1, and TASK1) did not detect sex differences. Conclusions — This mouse model reveals sex difference in response to a pharmacological challenge yet does not display sex differences in standard electrophysiological parameters. Differences in KCNE1 may contribute to sex differences uncovered by halothane.

Drug-induced torsade de pointes is a rare life-threatening adverse drug reaction (ADR) which is strongly influenced by gender. Drugs that prolong cardiac repolarisation include antiarrhythmics, gastrokinetics, antipsychotics, antihistamines and antibacterials. Such drugs share the potential to block cardiac voltage-gated potassium channels, particularly the rapid component (I(Kr)) of the delayed rectifier potassium current (I(K)). By doing so, such drugs usually, but not always, prolong the QT interval. Even if the electrocardiographic signs are subdued, the underlying blockade of I(Kr) current may precipitate the occurrence of arrhythmia. Women are perceived to be more prone to ADRs than men. Such a propensity may result from gender-associated differences in drug exposure, in the number of drugs prescribed (polypharmacy), in drug pharmacology, as well as from possible differences in the way the adverse event is perceived. A prolonged QT interval on the electrocardiogram (time that elapses from the onset of the cardiac ventricular depolarisation to the completion of its repolarisation) is associated with the occurrence of torsade de pointes and related ventricular arrhythmias. The QT interval is influenced by heart rate, autonomic nervous system, electrolyte disturbances and above all, drugs that block potassium channels. Two-thirds of the cases of drug-induced torsade de pointes occur in women. Therefore, this adverse effect represents a perfect example of gender differences impairing women's health. Clinical and experimental studies show that female gender is associated with a longer corrected QT interval at baseline and a greater response to drugs that block I(Kr), both of which facilitate the emergence of arrhythmia. This results most likely from a specific regulation of ionic channel expression (potassium, calcium, etc) by sex steroids, even though nongenomic effects may play a role as well. Estrogens facilitate bradycardia-induced prolongation of the QT interval and the emergence of arrhythmia whereas androgens shorten the QT interval and blunt the QT response to drugs. Hence, underlying genetic defects of potassium channels that may be asymptomatic in normal conditions, may precipitate drug-induced arrhythmia in women more frequently than in men. Even in the presence of a drug that mildly blocks I(Kr) and seldom prolongs the QT interval, women are still more prone to drug-induced torsade de pointes, due to their reduced cardiac 'repolarisation reserve'. This is an important aspect of I(Kr) blockade to be aware of during the development of new drugs.

The voltage-dependent K + channel responsible for the slowly activating delayed K + current I Ks is composed of pore-forming KCNQ1 and regulatory KCNE1 subunits, which are mutated in familial forms of cardiac long QT syndrome. Because KCNQ1 and KCNE1 genes also are expressed in epithelial tissues, such as the kidneys and the intestine, we have investigated the adaptation of KCNE1-deficient mice to different K + and Na + intakes. On a normal K + diet, homozygous kcne1 −/− mice exhibit signs of chronic volume depletion associated with fecal Na + and K + wasting and have lower plasma K + concentration and higher levels of aldosterone than wild-type mice. Although plasma aldosterone can be suppressed by low K + diets or stimulated by low Na + diets, a high K + diet provokes a tremendous increase of plasma aldosterone levels in kcne1 −/− mice as compared with wild-type mice (7.1-fold vs. 1.8-fold) despite lower plasma K + in kcne1 −/− mice. This exacerbated aldosterone production in kcne1 −/− mice is accompanied by an abnormally high plasma renin concentration, which could partly explain the hyperaldosteronism. In addition, we found that KCNE1 and KCNQ1 mRNAs are expressed in the zona glomerulosa of adrenal glands where I Ks may directly participate in the control of aldosterone production by plasma K + . These results, which show that KCNE1 and I Ks are involved in K + homeostasis, might have important implications for patients with I Ks -related long QT syndrome, because hypokalemia is a well known risk factor for the occurrence of torsades de pointes ventricular arrhythmia.

This chapter focuses on the molecular basis of long QT syndromes (LQTS) and cardiac arrythmias. The molecular genetic approach including linkage analysis performed in large families has identified five loci responsible for the LQTS. Since the first discovery of a locus associated with congenital (LQTS), at least 14 different loci and four different genes have been held accountable for inherited cardiac arrhythmias. These four genes all encode for ion channel subunits involved in generating the cardiac action potential.. The phenotype of both Jervell and Lange-Nielsen (JLN) and Romano–Ward (RW) LQTS is characterized by a prolonged QT duration on a surface electrocardiograph (ECG) and by an abnormal T wave morphology. Clinically, the QT interval is longer in females as compared to males, and in addition, a moderate sinus bradycardia is often present. QT prolongation could be considered per se as a minor problem however, QT prolongation reveals a major abnormality of cardiac electrical repolarization, which may eventually lead to complex cardiac ventricular arrhythmias and death. The LQTS is characterized by paroxystic life-threatening polymorphic ventricular tachycardias such as torsades de pointes. Syncopes typically occur during stress or physical exercise and for those prone to syncope, the mortality rate can be as high as 50% within the first year in the absence of treatment.

Objectives: We report the functional expression of four KCNQ1 mutations affecting arginine residues and resulting in Romano–Ward (RW) and the Jervell and Lange–Nielsen (JLN) congenital long QT syndromes. Results: The R539W and R190Q mutations were found in typical RW families with an autosomal dominant transmission. The R243H mutation was found in a compound heterozygous JLN patient who presents with deafness and cardiac symptoms. The fourth mutation, R533W, was a new case of recessive form of the RW syndrome since homozygous carriers experienced syncopes but showed no deafness, whereas the heterozygous carriers were asymptomatic. The R190Q mutation failed to produce functional homomeric channels. The R243H, R533W and R539W mutations induced a positive voltage shift of the channel activation but only when co-expressed with IsK, pointing out the critical role of these positively charged residues in the modulation of the gating properties of KvLQT1 by IsK. The positive shift induced by R533W was merely 15%. This small effect was compatible with the recessive character of the RW phenotype transmission. The average QTc was significantly longer ( P

Tegaserod (HTF 919) is a new drug being developed for gastrointestinal motility disorders. Because other gastrointestinal prokinetic agents, such as cisapride and erythromycin, cause slowing of cardiac repolarization and have been implicated in the development of the potentially fatal ventricular arrhythmia, torsades de pointes, a study was initiated to determine whether tegaserod and its main human metabolite adversely influence cardiac repolarization. By using isolated Langendorff-perfused rabbit hearts, we show that QT intervals remain unchanged at concentrations of tegaserod from 0.5 to 10 microM. It was not until the tegaserod concentration was increased to 50 microM (roughly 500-5,000 times more concentrated than those typically found in human plasma after administration of recommended clinical dosages), that a small, but significant increase in the QT interval (12+/-4%; p0.05; n = 4) was observed. No significant changes in QT occurred in the presence of the tegaserod metabolite at any of the concentrations tested (0.5-50 microM). In contrast, cisapride caused QT lengthening at concentrations as low as 0.1 microM, with significant QT increases occurring when 5-50 microM cisapride was used (22+/-4% to70%, respectively; p0.01; n = 4). Erythromycin also caused significant lengthening of QT intervals (11+/-2%; p0.001; n = 4), although 100 microM concentrations of this drug were required to achieve this effect. These results demonstrate that both cisapride and erythromycin can slow cardiac repolarization at therapeutic doses and that tegaserod's lack of QT prolongation at therapeutic doses suggests that it has the potential to be a safer alternative to cisapride as a gastrointestinal prokinetic agent.

Context.—Erythromycin is a widely used antibiotic that infrequently causes QT-prolongation and torsades de pointes cardiac arrhythmias. For antiarrhythmic drugs, women are at a higher risk for these cardiac arrhythmias, but few other classes of drugs have been studied.Objectives.—To determine whether female sex is a risk factor for cardiac arrhythmias associated with erythromycin, and if this can be correlated with in vitro measurements of the QT-response to erythromycin in male and female rabbit hearts.Design.—Food and Drug Administration (FDA) MEDWATCH database analysis and in vitro experiment.Main Outcome Measures.—Cardiac arrhythmia reports associated with erythromycin from 1970 until 1996 classified by patient sex and age, and effect of female sex on erythromycin-induced QT-prolongation in isolated perfused rabbit hearts.Results.—We observed a sex difference in cardiac arrhythmias associated with administration of erythromycin. A total of 346 cases were found in the FDA database: 201 females (58%), 110 males (32%), and 35 unspecified (10%). Forty-nine were life-threatening ventricular arrhythmias and deaths directly related to intravenous erythromycin lactobionate: 33 women (67%) and 16 men (33%) (P = .03). During the same period, no sex imbalance was present in the prescription pattern for intravenous erythromycin lacobionate (men 47%, women 49%, unspecified 4%). Perfusion with erythromycin caused significantly greater QT-prolongation in female rabbit hearts (mean [SD], 11.8% [2.3%]) than in male hearts (6.9% [2.1%]; P = .03).Conclusions.—As has been shown in reports of antiarrhythmic drugs, we found a female predominance in the FDA reports of erythromycin-associated cardiac arrhythmias. Based on in vitro experiments, a sex difference in cardiac repolarization response to erythromycin is a potential contributing factor.

We examined the effects of "conventional" antihistamines on cardiac repolarization by using the isolated perfused feline heart model. Representative drugs from the major classes of antihistamines were tested. Each of the antihistamines evaluated in this study elicited a dose-dependent slowing of cardiac repolarization, as indicated by the QT prolongations observed from electrocardiogram (ECG) tracings recorded during these experiments. The concentrations of drugs tested ranged from 1 to 30 microM. Of the drugs analyzed, clemastine and hydroxyzine appeared to be the most potent (relative EC50 values, 5.2 and 6.6 microM, respectively), causing the QT to lengthen by as much as 40-50% at a concentration of 10 microM. Brompheniramine, chlorpheniramine, and diphenhydramine displayed intermediate potencies with respect to QT prolongation (relative EC50 values, 11-13 microM), whereas cyproheptadine, chlorcyclizine, and promethazine were the least potent of the antihistamines tested (relative EC50 values, 16-20 microM). It is concluded that the antihistamines evaluated in this study act directly on the heart to slow cardiac repolarization. These findings could have important clinical relevance for patients taking excessive dosages of conventional antihistamines and those at risk of developing cardiac arrhythmias.

Abstract —The Jervell and Lange-Nielsen (JLN) syndrome affects the human cardioauditory system, associating a profound bilateral deafness with an abnormally long QT interval on the ECG. It results from mutations in KVLQT1 and ISK genes that encode the 2 subunits forming the K + channel responsible for the cardiac and inner ear slowly activating component of the delayed rectifier K + current ( I Ks ). A JLN mouse model that presents typical inner ear defects has been created by knocking out the isk gene ( isk −/−). This study specifically reports on the cardiac phenotype counterpart, determined in the whole animal and at mRNAs and cellular levels. Surface ECG recordings of isk −/− mice showed a longer QT interval at slow heart rates, a paradoxical shorter QT interval at fast heart rates, and an overall exacerbated QT–heart rate adaptation compared with wild-type (WT) mice. A 300-ms increase in the heart rate cycle length induces a 309±21% increase in the QT duration of the WT mice versus a 500±50% in isk −/− mice ( P isk gene product and/or I Ks , when present, blunts the QT adaptation to heart rate variations and that steeper QT-RR relationships reflect a greater susceptibility to arrhythmias in patients lacking I Ks .

A prospective case-control study was designed to confirm the higher plasma concentration of aluminium in primary spontaneous pneumothorax patients recently reported in literature. Ten consecutive patients with PSP entered the study. Comparison with the control group obtained from the database of the Pharmacology Department did not show any significant difference. The conclusion was that in patients with PSP from the Maritime Alps region aluminium concentration was not abnormal. Therefore, the study was stopped.

Introduction.Le dabigatran est un inhibiteur direct de la thrombine pour lequel il n’est pas nécessaire de suivre l’activité anticoagulante en routine selon le résumé des caractéristiques du produit. Notre objectif était de déterminer la pertinence d’un dosage en soins courants en comparant la concentration plasmatique de dabigatran chez les patients présentant un saignement sous traitement à ceux n’ayant pas de saignement.Matériel et méthode.Les patients admis au CHU de Nice et traités par dabigatran étaient inclus dans notre étude. Pour chaque séjour, des données sur le risque hémorragique (scores HAS-BLED et EMORR²HAGES) et le risque de thrombose (score CHA2DS2-VASc), la prescription de dabigatran et la présence d’un saignement étaient collectées. La concentration plasmatique de dabigatran était mesurée par chromatographie liquide couplée à un spectromètre de masse à partir de tubes provenant du laboratoire d’hématologie ou de biochimie. Le prélèvement avait été réalisé en soins courants pour une autre analyse effectuée par un de ces laboratoires. Résultats.Nous avons inclus 132 séjours et 71 dosages ont été inclus dans l’analyse. Le risque hémorragique entre les groupes est comparable selon le score HAS-BLED. La concentration plasmatique de dabigatran est un facteur de risque indépendant d’hémorragie sous dabigatran (p Discussion.La concentration de dabigatran était un facteur associé au risque hémorragique chez les patients traités en soins courants. Effectuer le dosage du dabigatran chez les patients à risque d’élévation de concentration est un moyen supplémentaire pour sécuriser la prescription de ce nouveau médicament.