|
| Risk factor | Causes/implications |
|
| Sex (female) | QT intervals longer in women than in men
QT interval longer during first half of menstrual cycle |
|
| Age (elderly) | Comorbid coronary artery diseases
Multiple medications
Pharmacokinetic/pharmacodynamic changes |
|
Electrolyte imbalance
Hypokalemia, hypomagnesemia
Hypocalcemia | Diuretic use
Excessive vomiting or diarrhea
Postprandial hypokalemia |
|
| Congenital long QT syndrome | Associated with torsade and sudden death |
|
| Cardiac disease with history of acute or chronic myocardial ischemia, CHF, cardiac arrhythmias, and bradycardia | Increased risk of cardiac arrhythmias |
|
| Drugs known to prolong QTc interval | May potentiate QTc prolongation |
|
| Medication overdose with drugs that prolong the QTc interval | QTc prolongation generally dose dependent |
|
| Concomitant medications, liver disease | Adverse events with cytochrome P-450 enzyme system inhibition, leading to increased drug levels that can increase QT interval |
|
Endocrine/metabolic disorders
Diabetes, obesity
Hypothyroidism, pituitary insufficiency | Via electrolytes or cardiovascular disease |
|
Injury to the central nervous system
Stroke, infection, and trauma | Via autonomic nervous system dysfunction |
|
