title: Chemotherapy and QT Prolongation: Overview With Clinical Perspective.
abstract: Cardiotoxic adverse events are of concern to physicians treating cancer patients; they are encountered with a variety of agents. Cardiac events may delay the approval of new drugs or impose burdensome monitoring requirements as either part of the pre-approval process or in the daily use of these agents. Among the cardiac issues are the development of QT prolongation and the fear of torsades de pointes (TdP), an unusual yet potentially fatal form of ventricular tachycardia associated with QT prolongation. Several risk factors, including electrolyte imbalance and polypharmacy with concomitant QT prolonging agents use can increase the risk of TdP in cancer patients; separating the individual contributions of the various triggers for TdP remains problematic. Understanding the individual risk of QT prolongation associated with particular chemotherapies can better differentiate between those shown to have higher risk vs. those with lower risk potential. Cardiac monitoring and electrocardiogram analysis require recognition of the common challenges with regard to the precise measurement of the QT interval such as the presence of U waves, intraventricular conduction delays, and heart rate correction. Rapid identification and treatment of QT prolongation and TdP is critical in mitigating the risk of sudden cardiac death in cancer patients. A multidisciplinary treatment approach among cardiologists and oncologists should be employed to help facilitate an appropriate balance between oncologic efficacy and adverse cardiac events.
authors.affiliation: Department of Cardiology, The University of Texas, MD Anderson Cancer Center, Houston, TX, 77030, USA.
authors.forename: Peter Y
authors.initials: PY
authors.lastname: Kim
authors.forename: Michael S
authors.initials: MS
authors.lastname: Ewer
references.citation: J Electrocardiol. 2004;37 Suppl:81-90
references.pmid: 15534815
references.citation: Anesthesiology. 2005 Jun;102(6):1101-5
references.pmid: 15915020
references.citation: Ann Oncol. 2012 Nov;23(11):2960-2963
references.pmid: 22745218
references.citation: Heart Rhythm. 2008 Jul;5(7):1015-8
references.pmid: 18598957
references.citation: J Pharmacol Toxicol Methods. 2013 Jul-Aug;68(1):13-22
references.pmid: 23538024
references.citation: Clin Cancer Res. 2009 Nov 1;15(21):6702-8
references.pmid: 19825948
references.citation: J Am Coll Cardiol. 2006 Sep 5;48(5):e247-346
references.pmid: 16949478
references.citation: Clin Cancer Res. 2009 Nov 15;15(22):7045-52
references.pmid: 19903787
references.citation: J Am Coll Cardiol. 2010 Mar 2;55(9):934-47
references.pmid: 20185054
references.citation: J Clin Oncol. 2003 Sep 1;21(17):3378-9
references.pmid: 12947082
references.citation: Blood. 2001 Jul 15;98(2):266-71
references.pmid: 11435292
references.citation: J Clin Oncol. 2001 Sep 15;19(18):3852-60
references.pmid: 11559723
references.citation: Fed Regist. 2005 Oct 20;70(202):61134-5
references.pmid: 16237860
references.citation: Cancer. 2010 Mar 15;116(6):1582-91
references.pmid: 20108303
references.citation: Circulation. 2007 Mar 13;115(10):1306-24
references.pmid: 17322457
references.citation: J Electrocardiol. 2009 Nov-Dec;42(6):534-42
references.pmid: 19700171
references.citation: Am J Cardiol. 2006 Oct 1;98(7):933-5
references.pmid: 16996877
references.citation: Circulation. 1997 Oct 7;96(7):2149-54
references.pmid: 9337183
references.citation: Am J Cardiol. 1994 Aug 15;74(4):357-62
references.pmid: 8059698
references.citation: Clin Cardiol. 2008 Jun;31(6):270-4
references.pmid: 18543308
references.citation: Eur Heart J. 1993 Nov;14 Suppl H:88-92
references.pmid: 8293758
references.citation: Clin Ther. 2008 Nov;30(11):1956-75
references.pmid: 19108785
references.citation: Clin Cancer Res. 2008 Sep 1;14(17):5325-31
references.pmid: 18765523
references.citation: Heart Rhythm. 2005 Jun;2(6):569-74
references.pmid: 15922261
references.citation: Cardiol J. 2008;15(5):408-21
references.pmid: 18810715
references.citation: Circulation. 2008 May 27;117(21):e350-408
references.pmid: 18483207
references.citation: Circ Arrhythm Electrophysiol. 2009 Apr;2(2):185-94
references.pmid: 19808464
references.citation: Am J Cardiol. 2004 Apr 15;93(8):1017-21
references.pmid: 15081446
references.citation: Circulation. 1988 Feb;77(2):392-7
references.pmid: 3338130
references.citation: Heart Rhythm. 2009 May;6(5):652-7
references.pmid: 19303371
references.citation: Eur J Pharmacol. 2013 Apr 5;705(1-3):1-10
references.pmid: 23474023