As a medical professional with expertise in cardiology, I can provide you with information on what can cause QT prolongation. The QT interval on an electrocardiogram (ECG) represents the time between the start of the Q wave and the end of the T wave, which corresponds to the time between the initial depolarization and the completion of repolarization of the ventricles. Prolongation of the QT interval can lead to a serious condition known as Torsades de Pointes, which is a type of life-threatening ventricular arrhythmia. Several factors can contribute to QT prolongation, including: 1. Genetic factors: Certain inherited conditions, such as congenital long QT syndrome (LQTS), can cause QT prolongation. 2. Medication side effects: A number of medications, including some antiarrhythmic drugs, antibiotics, antipsychotics, and antidepressants, are known to prolong the QT interval. 3. Electrolyte imbalances: Low levels of potassium (hypokalemia) or magnesium (hypomagnesemia) can lead to QT prolongation. 4. Cardiac conditions: Certain heart diseases, such as myocardial infarction, can affect the QT interval. 5. Endocrine disorders: Conditions like hypothyroidism can cause QT prolongation. 6. Neurotransmitter imbalances: Imbalances in the brain's neurotransmitters can affect the heart's electrical activity. 7. Hormonal changes: Some studies suggest that hormonal fluctuations, particularly in women, may influence the QT interval. 8. Acute medical illnesses: Conditions like sepsis or stroke can also cause QT prolongation. It's important to note that not all cases of QT prolongation are caused by the factors listed above, and a thorough medical evaluation is necessary to determine the underlying cause. read more >>

The majority (80�C85%) of sudden cardiac deaths is caused by acute ventricular arrhythmia [5]. An important potential cause of ventricular arrhythmia is prolongation of ventricular repolarization, for instance, as is observed in the rare and genetically-determined 'congenital long QT syndrome' (LQTS) [6].read more >>