What is it about?
Patients diagnosed with non-ischemic dilated cardiomyopathy (NIDCM) (not due to ischemic, hypetensive or valvular heart disease) are at risk for both pump failure and sudden cardiac death (SCD). Assessing the risk of SCD in NIDCM remains a challenge for clinicians. Current guidelines for implantable cardioverter defibrillator (ICD) implantation in patients with NIDCM are based on debatable predictors, such as depressed left ventricular (LV) ejection fraction (LVEF) and New York Heart Association (NYHA) functional class, criteria that are neither specific nor sensitive enough to adequately identify the highest risk patients. The main problem is that many patients who receive an ICD device based on LVEF <35% may not really be at high risk for SCD while they are also exposed to the devices’ untoward effects. On the other hand, a lot of patients with LVEF >35%, thus not fitted with an ICD according with current guidelines, might suffer a SCD and thus they remain unprotected. Thus, this important issue of how to assess the risk for SCD is discussed in this article.
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Why is it important?
Currently, the indication for implantation of an ICD for primary prevention of SCD in NIDCM is mainly an LVEF < 35%. However, SCD can also occur in patients with LVEF>35%. A newer tool that has emerged that can be used to assess the risk for sudden death in patients NIDCM is cardiac magnetic resonance imaging (CMR) with late gadolinium enhancement (LGE) which is able to detect myocardial fibrosis which appears to confer a higher risk. Thus, CMR positive patients will need protection with implantation of an ICD device, while CMR negative patients will not, regardless of LVEF. ● A resurgence of an old tool, the electrophysiology study (EPS) with programmed ventricular stimulation may enhance our ability to assess the risk in patients with NIDCM. Patients with inducible sustained ventricular arrhythmia at EPS will need an ICD, while those with no arrhythmia induced, will not. ● Thus, based on old and new tools, a more individualized approach may need to be applied in NIDCM patients, whereby CMR and EPS findings may provide some further guidance, that may include patients with LVEF >35%, whereby SCD still prevails.
Perspectives
I hope this article may provide some insight into the problem of assessing the risk of sudden death in this particular group of patients, i.e. patients with non-ischemic dilated cardiomyopathy (NIDCM), by helping one understand that there is progress in this challenging problem by two ways, one is non-invasive, and more practical, i.e. the use of cardiac magnetic resonance imaging (CMR), and the other invasive, i.e. the performance of an electrophysiology study. Use of these tools may help refine risk stratification for both groups of patients, those with an LVEF <35%, who, by current guidelines should have an ICD, however, when CMR is negative, one may re-consider this option, and in those with LVEF >35%, who, by current guidelines should not have an ICD, but if CMR is positive, one may opt for an ICD, especially, if an EPS is also positive.
Professor Antonis S Manolis
Athens University School of Medicine
Read the Original
This page is a summary of: Sudden death risk stratification in non-ischemic dilated cardiomyopathy using old and new tools: a clinical challenge, Expert Review of Cardiovascular Therapy, March 2017, Taylor & Francis,
DOI: 10.1080/14779072.2017.1307735.
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