Protected from torsades de pointes? What psychiatrists need to know about pacemakers and defibrillators

Consultation-liaison (C-L) psychiatrists are frequently asked to initiate and manage psychotropic drugs, some of which can delay cardiac repolarization, prolong the QT interval, and increase the risk of torsades de pointes (TdP). This task is complicated by the growing number of patients with cardiovascular implantable electronic devices (CIED) [i.e., permanent pacemakers (PPM), implantable cardioverter defibrillators (ICD), and cardiac resynchronization therapy devices (CRT)]. The precise protective role of CIEDs in the prevention and treatment of TdP is not well-defined.

We review practical tips for assessment of the QT interval in patients with paced rhythms, as well as the basic operative principles of CIEDs. We examine the available clinical evidence for the use of CIEDs in patients at risk for TdP.

Most CIEDs have a pacing function that, when utilized appropriately, can offer partial protection against TdP by prevention of bradycardia. Defibrillators deliver shocks and are reasonably effective at terminating TdP; however, recurrent shocks are common and are associated with significant physical and psychological morbidity.

CIEDs are important tools in the management of drug-induced ventricular arrhythmias in spite of significant limitations. The C-L psychiatrist should remain vigilant in recognizing and managing patients at risk for TdP, and refrain from over-reliance on CIEDs regardless of type or settings. Ultimately, the presence of a CIED should serve as a marker of increased risk of TdP.