Details concerning patients with selective oestrogen receptor modulators (SERMs)-associated long QT syndrome with no ventricular arrhythmias (n=30) collected from VigiBase (last accessed in September 2017) and PubMed (last accessed in December 2017)
| Characteristic | Number (%) | Number with available data |
| Female gender | 19 (66) | 29 |
| Age (years) | 27 | |
| <18 | 3 (11) | |
| 18–64 | 15 (56) | |
| 65–85 | 8 (29) | |
| >85 | 1 (4) | |
| Indication | 20 | |
| Breast cancer | 11 (55) | |
| Meningioma, glioma | 3 (15) | |
| Other | 6 (30) | |
| Region of reporting | 25 | |
| Americas | 9 (36) | |
| Europe | 13 (52) | |
| Asia | 2 (8) | |
| Oceania | 1 (4) | |
| Other concomitant reported suspected medications* | 30 | |
| None (only SERMs) | 18 (60) | |
| One other | 10 (33) | |
| Two others | 2 (7) | |
| Regimen of culprit drug | 30 | |
| Tamoxifen (10–30 mg/day; oral) | 17 (57) | |
| Tamoxifen (100–300 mg/day; oral) | 4 (13) | |
| Tamoxifen (dose unknown) | 4 (13) | |
| Toremifene (300 mg/day; oral) | 5 (17) | |
| Magnitude of QTc prolongation | 10 | |
| QTc (470–500 ms) | 1 (10) | |
| QTc >500 ms | 9 (90) | |
| Concurrent reported condition favouring LQT syndrome | 30 | |
| Hypokalaemia, hypomagnesaemia | 1 (3) | |
| Cardiac conditions (ischaemia, heart failure) | 2 (6) | |
| Bradycardia | 2 (6) | |
| Atrial fibrillation | 2 (6) | |
| Reporting year | 30 | |
| 1990–2004 | 6 (20) | |
| 2005–2010 | 4 (13) | |
| 2011–2017 | 20 (67) | |
| Reporter qualification | 29 | |
| Health professional | 25 (86) | |
| Consumer (non-health professional) | 4 (14) | |
| Time to onset, median (IQR) days | 7 (5–66.5) | 21 |
| (Min, max) days | (1, 1415) | |
*Other concomitant reported suspected medications were hydrochlorothiazide (n=1), glycopyrronium (n=1), antidepressant drugs (n=3), class III antiarrhythmic drugs (n=2), fluoroquinolone (n=2), acitretin (n=1), ACE inhibitor (n=1) and anticancer drugs (n=3).