The wearable external cardiac defibrillator for cancer patients at risk for sudden cardiac death
The wearable external cardiac defibrillator (WCD) may be utilized for patients at risk for sudden cardiac death (SCD) for whom an implantable cardiac defibrillator (ICD) is problematic. The purpose of our study was to describe the use and limitations of the WCD in a cohort of cancer patients. Deidentified records from patients prescribed the WCD between 2005 and 2009 were reviewed, and patients with a history of cancer were included. Among 23,797 patients prescribed the WCD, 59 (0.02%) had cancer. A defibrillator was indicated in 54 of the 59 patients, based on poor ventricular function. The remaining five patients had a prior life-threatening arrhythmia. A previously implanted ICD was removed due to infection or thrombus in 6 of the 59 patients (10%). Successful shocks were delivered on 5 occasions to 4 of the 59 patients (7%) within 3 months. Among 11 deaths, none was due to noncompliance or WCD treatment failure. Limitations of the study include its retrospective nature and the minimal information available in the dataset. Nonetheless, it provides important information in that the study includes all patients with a history of cancer prescribed the WCD in a contemporary cohort. The WCD may protect cancer patients at risk for SCD until an ICD can be safely implanted or is deemed unnecessary.
Implantable cardioverter defibrillators (ICDs) are indicated for primary prevention of sudden cardiac death (SCD) in patients with reduced left ventricular function (an ejection fraction of ≤ 35%). ICD therapy is also recommended for secondary prevention of SCD in patients with a life-threatening cardiac arrhythmia, including aborted sudden cardiac death. Contraindications to ICD therapy are life expectancy ≤ 1 year, incessant arrhythmia, significant psychiatric illness, syncope without evidence of inducible ventricular arrhythmia or structural heart disease, ventricular arrhythmia amenable to catheter ablation, ventricular arrhythmia due to a reversible cause, and primary prevention of SCD in patients ineligible for cardiac transplantation or cardiac resynchronization therapy.1 In addition, relative contraindications to ICD therapy include the need for radiation therapy to the thorax, high risk for infection, and high risk for deep venous thrombosis.
A subset of patients with cancer is at risk for SCD due to a variety of cardiac causes, including chemotherapy-induced cardiomyopathy or druginduced long QT syndrome. These patients may benefit from ICD placement. However, the aforementioned relative contraindications for permanent defibrillator implantation often coexist in patients with cancer. Moreover, an individual with acute malignancy may have other contraindications for permanent defibrillator implantation, including the potential reversibility of cardiomyopathy or arrhythmia or an unclear prognosis for 1-year survival. ...
* For a PDF of the full article, click in the link to the left of this introduction.
