More Guidance Regarding Which Patients Should be Treated with Implantable Defibrillator Therapy

Three years ago, Dr. Al-Khatib and colleagues published a high-profile study using data from the NCDR ICD Registry reporting that 23% of ICD implants are “non-evidence-based”.¹ Unfortunately, the message that was taken away from the study by many was that physicians are implanting too many ICDs that are not indicated. Although it is likely that there are some patients undergoing ICD implantation who might not benefit, a much bigger problem is that the device guidelines do not apply to many common scenarios encountered in clinical practice. For example, should a patient with a severe ischemic cardiomyopathy who develops permanent heart block after cardiac bypass surgery and aortic valve replacement really be treated with only a pacemaker rather than an ICD, just because the “guidelines” state that one must wait 90 days after revascularization before implanting an ICD for primary prevention? Unfortunately, since publication of this paper, the heart rhythm community has had a lot of explaining to do. Much time, resources, and energy have been devoted to damage control. 

Last year, appropriate use guidelines were published to better define when ICD therapy is reasonable in situations when the guidelines do not precisely apply. Although it can be challenging to determine where an individual patient fits into the numerous scenarios that are presented, they were a strong effort and provide useful guidance.

In the July 2014 issue of HeartRhythm, Dr. Kusumoto and colleagues offer an Expert Consensus Statement² that is succinct and provides guidance in circumstances when a patient does not fit neatly into the ACC/AHA/HRS device guidelines. The primary focus of the document was to address four common clinical scenarios — ICD indications for primary prevention that were considered “non-evidence-based” in the Al-Khatib paper. Here is an abbreviated list of ten of the recommendations from the document, categorized by general scenario:

ICD implantation in the context of an abnormal troponin that is not due to a myocardial infarction:

1. “In patients with abnormal cardiac biomarkers that are not thought to be due to an MI and who otherwise would be candidates for implantation on the basis of primary prevention or secondary prevention criteria, implantation of an ICD is recommended.”²

ICD implantation within 40 days of a myocardial infarction:

2. “Implantation of an ICD within the first 40 days following acute MI in patients with preexisting systolic ventricular dysfunction (who would have qualified for a primary prevention ICD) is not recommended.”²

3. “In patients who, within 40 days of an MI, require nonelective permanent pacing, who also would meet primary prevention criteria for implantation of an ICD, and recovery of left ventricular function is uncertain or not expected, implantation of an ICD with appropriately selected pacing capabilities is recommended.”² 

4. “In patients who, within 40 days of an MI, present with syncope that is thought to be due to ventricular tachyarrhythmia (by clinical history, documented NSVT, or electrophysiologic study), implantation of an ICD can be useful.”²

ICD implantation within 90 days of revascularization:

5. “In patients who are within 90 days of revascularization and who previously qualified for the implantation of an ICD for primary prevention of sudden cardiac death, and who have undergone revascularization that is unlikely to result in an improvement in LVEF, and who are not within 40 days after an acute MI, implantation of an ICD can be useful.”²

6. “In patients within 90 days of revascularization who require nonelective permanent pacing, who would also meet primary prevention criteria for implantation of an ICD, and in whom recovery of left ventricular function is uncertain or not expected, implantation of an ICD with appropriately selected pacing capabilities is recommended.”²

7. “In patients within 90 days of revascularization present with syncope that is thought to be due to ventricular tachyarrhythmia (by clinical history or documented NSVT, or EP study), implantation of an ICD can be useful.”²

ICD implantation within 9 months from the initial diagnosis of nonischemic cardiomyopathy:

8. “If recovery of left ventricular function is unlikely, implantation of an ICD for primary prevention can be useful between 3 and 9 months after initial diagnosis of NICM.”²

9. “In patients >9 months from the initial diagnosis of NICM who require nonelective permanent pacing, who would meet primary prevention criteria for implantation of an ICD, and recovery of left ventricular function is uncertain or not expected, implantation of an ICD with the appropriately selected pacing abilities is recommended.”²

10. “In patients >9 months from the initial diagnosis of NICM with syncope that is thought to be due to a ventricular tachyarrhythmia (by clinical history or documented NSVT), implantation of an ICD can be useful.”²

This Expert Consensus Statement addresses when ICD therapy is reasonable in patients who are not represented in the latest ICD guidelines, and is a welcome contribution. It provides further guidance to physicians and other health care providers who are doing their best to take care of patients. One can only hope that the ICD reimbursement guidelines can be updated soon to reflect modern expert opinion and evidence.

References

1. Al-Khatib SM, Hellkamp A, Curtis J, et al. Non-evidence-based ICD implantations in the United States. JAMA. 2011;305(1):43-49.
2. Kusumoto FM, Calkins H, Boehmer J, et al. HRS/ACC/AHA Expert Consensus Statement on the Use of Implantable Cardioverter-Defibrillator Therapy in Patients Who Are Not Included or Not Well Represented in Clinical Trials. Heart Rhythm. 2014;11:1271-1304.