Iatrogenic life-threating condition in a patient with multiple rare disorders

Andersen–Tawil syndrome (long QT syndrome 7) is a rare inherited disorder, characterized by periodic paralysis, long QT, ventricular arrhythmias and skeletal abnormalities.A 52-year-old female with a history of long QT-syndrome, ICD implantation (secondary prevention of cardiac arrest) and systemic vasculitis was admitted due to an electrical storm caused by endocarditis. She was admitted again short after discharge due to multi-organ failure, which was caused probably by withdrawal of steroids and VKA. Characteristic dysmorphic features resulted in Andersen–Tawil syndrome suspicion.If patients have one rare disorder they should not be excluded from further diagnostics, and very detailed outpatient care.     

Effet d’un effort intermittent d’intensité variable sur la variation du QT et du risque de mort subite chez des élèves camerounais

IntroductionSeveral cases of sudden deaths are observed among students practicing sport and physical activity (SPA). Just few studies have been carried out on the variation of the QT (interval) and risk of sudden death during sporting exercises.AimTo determine the effect of variable intermittent stress intensity on the variation of QT and the risk of sudden cardiac death.Patients and methodsForm 4, lower sixth and upper sixth students were recruited from a high school in Douala (Cameroon). Each subject was tested; starting with a 2-km walk followed by a sprint race or an endurance race, protocol I (P1) or the reverse; protocol II (P2). Two electrocardiograms were recorded; prior to the beginning of the SPA and 5 minutes after the last race. QT was corrected using four formulas.ResultsForty-one subjects (21 women and 20 men), mean age 18 ± 2 years were recruited. At the end of the exercise, corrected QT increased with Bazzet's formula and decreased with Frahmingam's formula. The difference was not significant with Fridericia and Hodges formulas. The frequency of long QT was higher at the end of the exercise with Bazzet's formula (12.2% vs. 24.4%, P = 0.009) while the difference was not significant for the other formulas.ConclusionThe risk of sudden cardiac death increases significantly after SPA. More studies on large samples are needed.     

The Measurement of the QT Interval

The evaluation of every electrocardiogram should also include an effort to interpret the QT interval to assess the risk of malignant arrhythmias and sudden death associated with an aberrant QT interval. The QT interval is measured from the beginning of the QRS complex to the end of the T-wave, and should be corrected for heart rate to enable comparison with reference values. However, the correct determination of the QT interval, and its value, appears to be a daunting task. Although computerized analysis and interpretation of the QT interval are widely available, these might well over- or underestimate the QT interval and may thus either result in unnecessary treatment or preclude appropriate measures to be taken. This is particularly evident with difficult T-wave morphologies and technically suboptimal ECGs. Similarly, also accurate manual assessment of the QT interval appears to be difficult for many physicians worldwide. In this review we delineate the history of the measurement of the QT interval, its underlying pathophysiological mechanisms and the current standards of the measurement of the QT interval, we provide a glimpse into the future and we discuss several issues troubling accurate measurement of the QT interval. These issues include the lead choice, U-waves, determination of the end of the T-wave, different heart rate correction formulas, arrhythmias and the definition of normal and aberrant QT intervals. Furthermore, we provide recommendations that may serve as guidance to address these complexities and which support accurate assessment of the QT interval and its interpretation.     

Neurocognitive and psychiatric disorders-related axonal degeneration in Parkinson's disease

Neurocognitive and psychiatric disorders have significant consequences for quality of life in patients with Parkinson's disease (PD). In the current study, we evaluated microstructural white matter (WM) alterations associated with neurocognitive and psychiatric disorders in PD using neurite orientation dispersion and density imaging (NODDI) and linked independent component analysis (LICA). The indices of NODDI were compared between 20 and 19 patients with PD with and without neurocognitive and psychiatric disorders, respectively, and 25 healthy controls using tract-based spatial statistics and tract-of-interest analyses. LICA was applied to model inter-subject variability across measures. A widespread reduction in axonal density (indexed by intracellular volume fraction [ICVF]) was demonstrated in PD patients with and without neurocognitive and psychiatric disorders, as compared with healthy controls. Compared with patients without neurocognitive and psychiatric disorders, patients with neurocognitive and psychiatric disorders exhibited more extensive (posterior predominant) decreases in axonal density. Using LICA, ICVF demonstrated the highest contribution (59% weight) to the main effects of diagnosis that reflected widespread decreases in axonal density. These findings suggest that axonal loss is a major factor underlying WM pathology related to neurocognitive and psychiatric disorders in PD, whereas patients with neurocognitive and psychiatric disorders had broader axonal pathology, as compared with those without. LICA suggested that the ICVF can be used as a useful biomarker of microstructural changes in the WM related to neurocognitive and psychiatric disorders in PD.     

An antibiotic recipe for an arrhythmic disaster

We describe the case of a patient who developed torsade de pointes during temporary pacemaker insertion after administration of intravenous erythromycin. The case highlights the dangers of administering drugs that prolong the QT interval in patients with complete atrioventricular block, and we discuss the underlying pathophysiological recipe that can lead to a potential arrhythmic disaster.