Drug‐induced long QT syndrome and fatal arrhythmias in the intensive care unit

Abstract

Long QT syndrome (LQTS) is a genetic or acquired condition characterised by a prolonged QT interval on the surface electrocardiogram (ECG) and is associated with a high risk of sudden cardiac death because of polymorph ventricular tachyarrhythmia called Torsade de Pointes arrhythmia. Drug-induced LQTS can occur as a side effect of commonly used cardiac and non-cardiac drugs in predisposed patients, often with baseline QT prolongation lengthened by medication and/or electrolyte disturbances. Hospitalised patients often have several risk factors for proarrhythmic response, such as advanced age and structural heart disease. Patients in the intensive care unit (ICU) are particularly prone to develop drug induced LQTS because they receive several different intravenous medications. Additionally, they might have impaired drug elimination because of reduced kidney and/or liver function, and also drug-drug-interactions. The clinical symptoms and signs of LQTS range from asymptomatic patients to sudden death because of malignant arrhythmias, and it is therefore important to recognise the clinical characteristics and typical ECG changes. Treatment of acquired LQTS is mainly awareness, identification and discontinuation of QT prolonging drugs, in addition to eventually supplement of magnesium and potassium. Overdrive cardiac pacing is highly effective in preventing recurrences, and antiarrhythmic drugs should be avoided. Recent data suggest that QT prolongation is quite common in ICU patients and adversely affects patient mortality. Thus, high-risk patients should be sufficiently monitored, and the use of medications known to cause drug-induced LQTS might have to be restricted.

Hidden Reason for Long QT

“…First goal in drug related long QT is discontinuation of the drug, magnesium and potassium replacement is also effective to stop the episodes. Antiarrhythmic drugs should be avoided in addition to overdrive cardiac pacing is highly effective [5].…”

Cardiac Ion Channel Regulation in Obesity and the Metabolic Syndrome: Relevance to Long QT Syndrome and Atrial Fibrillation

“…LQTS underlain by congenital mutations in ion channel subunits is somewhat rare and only affect ~1 in 2000 births (Schwartz et al, 2009; Beitland et al, 2014). In most cases life-threatening arrhythmias are triggered during emotional stress (fear, anger, postpartum state, and loud noises), exercise especially during swimming (Splawski et al, 2000), and by obesity and/or obesity-related diseases (Scherer and Hill, 2016).…”

“…In most cases life-threatening arrhythmias are triggered during emotional stress (fear, anger, postpartum state, and loud noises), exercise especially during swimming (Splawski et al, 2000), and by obesity and/or obesity-related diseases (Scherer and Hill, 2016). LQTS is also drug-induced and is the more common form (Kannankeril et al, 2010; Beitland et al, 2014). Therefore, it is relevant to determine the impact of the functional interplay between these triggers, and how they affect disease outcomes.…”

Propofol-associated QTc prolongation

“…Prolongation of the QTc interval is associated with increasing risk for fatal ventricular arrhythmias; therefore, ECG monitoring is recommended if there is a risk of QTc prolongation [Bazett, 1997;Fridericia, 2003;Drew et al 2010;Yap and Camm, 2003]. The risk of QTc prolongation is greater in the ICU for multiple reasons, including acute or unstable disease, the potential for electrolyte imbalances, and possible exposure to QTc prolonging medications [Drew et al 2004;Viskin et al 2003;Beitland et al 2014]. Medications known to increase the risk of QTc interval prolongation and arrhythmia risk include antiarrhythmic agents, antipsychotics, tricyclic antidepressants, fluoroquinolones, macrolides and azole antifungals [Drew et al 2010;Yap and Camm, 2003;Viskin et al 2003;Beitland et al 2014].…”

“…The risk of QTc prolongation is greater in the ICU for multiple reasons, including acute or unstable disease, the potential for electrolyte imbalances, and possible exposure to QTc prolonging medications [Drew et al 2004;Viskin et al 2003;Beitland et al 2014]. Medications known to increase the risk of QTc interval prolongation and arrhythmia risk include antiarrhythmic agents, antipsychotics, tricyclic antidepressants, fluoroquinolones, macrolides and azole antifungals [Drew et al 2010;Yap and Camm, 2003;Viskin et al 2003;Beitland et al 2014]. While the potential for QTc prolongation may be known for numerous medications, assessment of QTc interval changes for medications has only been required since 2005 [Darpo, 2010].…”