Open AccessIncidence and outcomes of long QT c in acute medical admissions
Author(s) -
Mahmud Rahel,
Gray Adam,
Nabeebaccus Adam,
Whyte Martin Brunel
Publication year - 2018
Publication title -
international journal of clinical practice
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.756
H-Index - 98
eISSN - 1742-1241
pISSN - 1368-5031
DOI - 10.1111/ijcp.13250
Subject(s) - medicine , qt interval , incidence (geometry) , long qt syndrome , prolongation , electrocardiography , cardiology , anesthesia , emergency medicine , physics , optics
Summary Aims Prolonged QT interval on electrocardiogram ( ECG ) increases the risk of ventricular arrhythmia. Patients admitted to acute medical units ( AMU ) may be at risk of QT prolongation from multiple, recognised risk factors. Few data exist regarding incidence or outcomes of QT prolongation in acute general medical admissions. The aims were to determine the incidence of Bazett's‐corrected QT ( QT c) prolongation upon admission to AMU ; the relationship between QT c and inpatient mortality, length of stay and readmission; proportion with prolonged QT c subsequently administered QT interval‐prolonging drugs. Methods Retrospective, observational study of 1000 consecutive patients admitted to an AMU in a large urban hospital. Exclusion criteria: age <18 years, ventricular pacing, poor quality/absent ECG . QT c determined manually from ECG obtained within 4‐hours of admission. QT c prolongation considered ≥470 milliseconds (males) and ≥480 milliseconds (females). In both genders, >500 milliseconds was considered severe. Study end‐points, (a) incidence of QT c prolongation at admission; (b) inpatient mortality, length of stay and readmission rates; (c) proportion with QT c prolongation subsequently administered QT interval‐prolonging drugs. Results Of 1000 patients, 288 patients were excluded, therefore final sample was n = 712. Patient age (mean ± SD ) was 63.1 ± 19.4 years; females 49%. QT c prolongation was present in n = 50 (7%) at admission; 1.7% had QT c interval >500 ms. Of the 50 patients admitted with prolonged QT c, 6 (12%) were subsequently administered QT interval‐prolonging drugs. QT c prolongation was not associated with worse inpatient mortality or readmission rate. Length of stay was greater in those with prolonged QT c, 7.2 ( IQR 2.4‐13.2) days vs 3.3 ( IQR 1.3‐10.0; P = 0.004), however, in a regression model, presence of QT c did not independently affect length of stay. Conclusions QT c interval prolongation is frequent among patients admitted to AMU . QT interval‐prolonging drugs are commonly prescribed to patients presenting with prolonged QT c but whether this affects clinical outcomes is uncertain.