Long-term proarrhythmic pharmacotherapy among patients with congenital long QT syndrome and risk of arrhythmia and mortality.

AIMS: It is Class I recommendation that congenital long QT syndrome (cLQTS) patients should avoid drugs that can cause torsades de pointes (TdP). We determined use of TdP risk drugs after cLQTS diagnosis and associated risk of ventricular arrhythmia and all-cause mortality. METHODS AND RESULTS: Congenital long QT syndrome patients (1995-2015) were identified from four inherited cardiac disease clinics in Denmark. Individual-level linkage of nation-wide registries was performed to determine TdP risk drugs usage (www.crediblemeds.org) and associated risk of ventricular arrhythmias and all-cause mortality. Risk analyses were performed using Cox-hazards analyses. During follow-up, 167/279 (60%) cLQTS patients were treated with a TdP risk drug after diagnosis. Most common TdP risk drugs were antibiotics (34.1%), proton-pump inhibitors (15.0%), antidepressants (12.0%), and antifungals (10.2%). Treatment with a TdP risk drug decreased 1 year after diagnosis compared with 1 year before (28.4% and 23.2%, respectively, P < 0.001). Five years after diagnosis, 33.5% were in treatment (P < 0.001). Risk factors for TdP risk drug treatment were age at diagnosis (5-year increment) [hazard ratio (HR) = 1.07, confidence interval (CI) 1.03-1.11] and previous TdP risk drug treatment (HR = 2.57, CI 1.83-3.61). During follow-up, nine patients were admitted with ventricular arrhythmia (three were in treatment with a TdP risk drug). Eight patients died (four were in treatment with a TdP risk drug). No significant association between TdP risk drug use and ventricular arrhythmias or all-cause mortality was found (P = 0.53 and P = 0.93, respectively), but events were few. CONCLUSION: Torsades de pointes risk drug usage was common among cLQTS patients after time of diagnosis and increased over time. A critical need for more awareness in prescribing patterns for this high-risk patient group is needed.

Prevalence and significance of troponin elevations in patients without acute coronary disease.

BACKGROUND: Cardiac troponin T and I are important diagnostic and prognostic markers in patients with acute coronary syndrome (ACS). Troponin elevations in various non-ACS scenarios have been documented, but few studies have been conducted on the general hospitalized population, none compared the diagnostic performance of troponin I and T. METHODS AND RESULTS: Patients aged >18years (n=1097), consecutively admitted to a district hospital, were included in the study. Blood samples were collected at admission and analysed with three different troponin assays. Serum was available in 92.2%, giving a study population of 1012 patients (mean age 61.6years, 510 (50.4%) female). ACS was diagnosed among 125 (12.4%) of the patients. Remaining patients were admitted with a broad spectrum of medical and surgical conditions. Of the total population, sc-cTnI was above the 99th percentile in 93 (9.2%), hs-cTnI was above the 99th percentile in 80 (7.9%) and hs-cTnT was above the 99th percentile in 400 (39.5%) of the patients (p<0.001 for all differences). Hs-cTnT was stronger correlated with estimated glomerular filtration rate (r [2]=0.13 vs r [2]=0.06) and haemoglobin (r [2]=0.1 vs r2=0.02) than with hs-cTnI, none were correlated with C-reactive protein (r [2]=0.04 vs r [2]=0.02). The correlation between ln(hs-cTnT) and ln(hs-cTnI) was better in ACS patients than in non-ACS patients (r [2]=0.79 vs r [2]=0.47, p<0.001). CONCLUSION: Hs-cTnT was elevated above the 99th percentile in more than one third of the non-ACS patients, while hs-cTnI and sc-cTnI were elevated in approximately one tenth. The correlation between hs-cTnT and hs-cTnI concentrations was significantly stronger in ACS patients than in non-ACS patients.