ABSTRACT
The QT interval is the most widely used ECG parameter for the assessement of myocardial repolarization and the risk of torsades de pointes. Measured from the beginning of the QRS complex, it is also influenced by the duration of the depolarization phase. The presence of ventricular conduction abnormalities or a widening of the QRS during ventricular pacing prolongs the QT interval, even if the repolarization phase is normal. Consequently, it is difficult to assess the QT interval in this population and to estimate the risk of torsades de pointes. In this article, we would like to give an overview of the current literature as guidance to the measurement of the QT interval in the presence of a QRS widening.
Subject(s)
Electrocardiography/methods , Long QT Syndrome/diagnosis , Torsades de Pointes/diagnosis , Arrhythmias, Cardiac/diagnosis , Arrhythmias, Cardiac/physiopathology , Humans , Long QT Syndrome/physiopathology , Risk , Torsades de Pointes/physiopathologyABSTRACT
For several decades, treating patients with pacemakers has been the privilege of cardiologists. However, in the last 30 years, researchers have found new targets for electrical stimulation in different clinical subspecialities, such as deep brain stimulation (for the treatment of Parkinson's disease, essential tremor, dystonia, and some psychiatric illnesses); spinal cord stimulation (for refractory angina, chronic pain, and peripheral artery disease); and sacral (for diverse urologic and proctologic conditions), vagal (for epilepsy), and phrenic nerve stimulation (for sleep apnoea). The purpose of this article is to familiarize cardiologists with these 'extra-cardiac pacemakers' and to discuss potential issues that must be addressed when these patients undergo cardiac procedures.
Subject(s)
Cardiologists/education , Electric Stimulation Therapy/instrumentation , Heart Diseases , Implantable Neurostimulators , Lumbosacral Plexus , Phrenic Nerve , Deep Brain Stimulation/instrumentation , Defibrillators, Implantable , Education, Medical , Electric Stimulation Therapy/adverse effects , Electric Stimulation Therapy/methods , Electrocardiography , Health Knowledge, Attitudes, Practice , Heart Diseases/diagnosis , Heart Diseases/physiopathology , Heart Diseases/therapy , Humans , Magnetic Resonance Imaging , Pacemaker, Artificial , Patient Safety , Predictive Value of Tests , Prosthesis Design , Prosthesis Failure , Reproducibility of Results , Risk Assessment , Risk Factors , Spinal Cord Stimulation/instrumentation , Treatment Outcome , Vagus Nerve Stimulation/instrumentationSubject(s)
Aortic Valve Insufficiency/surgery , Foreign-Body Migration/diagnostic imaging , Heart Valve Prosthesis/adverse effects , Iliac Artery/diagnostic imaging , Prosthesis Failure , Adult , Computed Tomography Angiography , Echocardiography , Heart Auscultation , Heart Murmurs/etiology , Humans , Male , Mitral Valve Prolapse/surgery , ReoperationABSTRACT
New assays with lower levels of detection of troponin (« high-sensitivity troponin ¼) increase the difficulty of interpretation of this test for the diagnosis of acute coronary syndrome in patients with chronic kidney disease (CKD). Their baseline concentration of troponin is frequently above the upper reference level, which lowers its specificity. To improve its diagnostic performance after clinical and electrocardiographic evaluation, cut-off levels 2 to 3 times higher than the standard reference have been suggested. Serial measurements can also add diagnostic value. In patients without acute coronary syndrome including patients with CKD, chronic elevation of troponin is a predictive factor of mortality. Its standardized measurement in clinical practice is still being investigated.
De nouvelles technologies permettant de diminuer le seuil de détection des troponines (troponines ultrasensibles) amènent des difficultés d'interprétation de ce test pour le diagnostic de syndrome coronarien aigu (SCA) lors d'insuffisance rénale chronique (IRC). Leur concentration est alors fréquemment au-dessus des valeurs de référence, ce qui en abaisse la spécificité. Pour en améliorer la performance diagnostique, après intégration des symptômes et du tracé électrocardiographique, il a été proposé d'augmenter de 2 à 3 fois la valeur seuil standard. Des dosages sériés peuvent également contribuer au diagnostic. Chez des patients sans SCA, l'élévation chronique des troponines, notamment lors d'IRC, représente également un facteur prédictif de mortalité. L'utilisation standardisée de ce dosage en pratique est encore en investigation.
