[Evaluation of rule out strategy for patients with non-ST-elevation acute coronary syndrome with single measurement of high-sensitivity cardiac troponin I from one sample tested beetween 3 and 6 hours after chest pain onset]. / Évaluation d'une stratégie d'exclusion d'un syndrome coronarien aigu non ST+ basé sur une unique mesure de troponine de haute sensibilité à partir d'un prélèvement effectué entre 3 et 6 heures après le début de la douleur.

BACKGROUND: Guidelines recommend to consider excluding non-ST-segment elevation myocardial infarction (NSTEMI) when high-sensitivity cardiac troponin is below the limit of quantification and a single blood sample is taken > 6 h after the onset of chest pain. The aim of our study was to assess such exclusion when a single blood sample was taken 3-6 h after the onset of permanent chest pain. METHODS: This observational study included consecutive patients admitted into the emergency room of our hospital with chest pain and suspected NSTEMI, with non-contributive electrocardiograms and a single high-sensitivity cardiac troponin I (hs-cTnI) blood sample taken 3-6 h after the onset of chest pain and hs-cTnI < 4 ng/l (Abbott Diagnostic). Clinical follow-up was undertaken 1 month after admission. RESULTS: The mean age of the 432 patients was 48.5 ± 5.6 years and 51% were male. Based on a clinical algorithm, the pre-test probability of NSTEMI was low in 70%, and intermediate in 21% of patients. Among 419 patients with available 1-month follow-up data, there were no myocardial infarctions or deaths. Thirty-eight patients (9%) were admitted into hospital but none for cardiac reasons. CONCLUSIONS: Our results suggest that exclusion of NSTEMI in patients with a non-contributive electrocardiogram and a single "negative" troponin test in a blood sample taken 3-6 h after the onset of symptoms is valid.

[Atrial fibrillation and QT prolongation due to proton pump inhibitor-induced hypomagnesemia]. / Fibrillation atriale et allongement du QT sur hypomagnésémie secondaire à un traitement par inhibiteur de la pompe à protons.

Proton pump inhibitors are widely prescribed but their long-term use can expose patients to adverse effects. Some of these are not very well known, including hypomagnesemia. Hypomagnesemia can be manifested by cardiac complications such as supraventricular arrhythmia or QT prolongation, increasing the risk of torsade de pointe. We present a case of atrial fibrillation triggered by severe hypomagnesemia secondary to proton pump inhibitor use and exacerbated by thiazide diuretic treatment. Conversion to sinus rhythm showed a prolonged corrected QT interval. We approach the pathophysiology and the electrophysiologic effects of hypomagnesemia.