Table 2.
| Modifiable risk factors |
| Electrolyte disturbances |
| Hypocalcemia (calcium <4.65 mg/dL) |
| Hypokalemia (potassium <3.4 mmol/L) |
| Hypomagnesemia (magnesium <1.7 mg/dL) |
| QT-prolonging medication polypharmacy |
| Concurrent use of ≥1 medication from www.crediblemeds.com |
| Nonmodifiable risk factors |
| Common diagnoses |
| Acute coronary syndrome |
| Anorexia nervosa or starvation |
| Bradyarrhythmias (heart rate <45 beats/min) |
| Cardiac heart failure (ejection fraction <40%; uncompensated) |
| Congenital long QT syndrome or other genetic susceptibility |
| Chronic renal failure requiring dialysis |
| Diabetes mellitus (types 1 and 2) |
| Hypertrophic cardiomyopathy |
| Hypoglycemia (documented and in the absence of diabetes) |
| Pheochromocytoma |
| Cardiac arrest within preceding 24 h |
| Syncope or seizure within preceding 24 h |
| Stroke, subarachnoid hemorrhage, or other head trauma within preceding 7 d |
| Clinical history |
| Personal or family history of QT-interval prolongation or sudden unexplained death in the absence of a clinical or genetic diagnosis |
| Demographic |
| Elderly (>65 y) |
| Female sex |
a
A “pro-QTc” score of ≥4 based on risk factors similar to those listed above was an independent predictor of mortality in patients with QT-interval prolongation.9 Unfortunately, the predictive value of these risk factors in patients with normal or borderline QT intervals has not been assessed.
b
SI conversion factors: To convert calcium values to mmol/L, multiply by 0.25; to convert magnesium values to mmol/L, multiply by 0.411.
Adapted from Neurogastroenterol Motil,10 with permission. © 2018 John Wiley & Sons Ltd.