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  • ACOEM Comments on Use of ICDs in Mariners

    October 9, 2012

    Docket Management Facility
    U.S. Department of Transportation
    1200 New Jersey Avenue SE, W12-140
    Washington, DC 20590

    Re: Docket No. USCG-20 72-0734, Medical Waivers for Merchant Mariner Credential Applicants with Anti-Tachycardia Devices or Implantable Cardioverter Defibrillators

    To Whom It May Concern:

    The American College of Occupational and Environmental Medicine (ACOEM) is pleased to provide comments on the US Coast Guard (USCG) Notice of Proposed policy change and request for comments. ACOEM is an organization of occupational medicine physicians and providers that service the nation’s workforce. Many of these physicians interact with the merchant mariner and water transportation industry.

    ACOEM has special interest sections of physicians working in the transportation industry and are familiar with the job requirements and credentialing process of merchant mariners. These comments are written from the perspective of ACOEM’s Transportation Section.

    The field of occupational medicine is considered a branch of preventive medicine and the physicians who become certified in this field have certificates from the American Board of Preventive Medicine. Although we commonly treat workplace injuries, our primary focus is on prevention rather than treatment.

    ACOEM appreciates the opportunity to comment on the US Coast Guard's proposed policy change regarding anti-tachycardia devices or implantable cardioverter defibrillators (ICDs). With regard to the specific questions seeking public comment, each must be considered with one overriding question. Is there an ICD still in place? The mere presence of a functioning ICD means that it could fire. ICDs have been known to fire in response to improperly sensing sinus tachycardia (usually a benign event) as requiring defibrillation. Additionally, the detection and interventional firing by the ICD, in itself, has been described as a severe jolt with possible loss of consciousness.

    If not incapacitating, it certainly would distract the mariner from his current duties or though process. A shock during the performance of activities such as climbing or emergency activities can place the mariner (and the public) at risk. Therefore, the mere presence of an ICD should remain as a disqualifying condition and not waiverable. Any of the questions below regarding the medical condition requiring the ICD or any other medical condition(s) should be addressed both individually and collectively as they may confound each condition. The ICD as an issue should not be waived unless it is no longer required and the ICD has been rendered non-functional (removal of the ICD or leads disconnected). Simply “turning off” the ICD does not render it non-functional. It can still be turned back on.

    1. Does the mariner have a diagnosis of cardiac channelopathy affecting the electrical conduction of the heart? The presence of an accurate diagnosis is required to establish the actual need for an ICD. If the original disease process that necessitated the placement of an ICD has resolved, and there are no other indications for the device, the mariner should have the device removed prior receiving a waiver.
    2. Does the mariner have a prior history of ventricular fibrillation or episodes of sustained ventricular tachycardia and, if so, did the arrhythmia episode occur greater than three years ago? An episode of ventricular fibrillation or ventricular tachycardia (with syncope or even death) during watch would likely have obvious devastating consequences. However, the presence of an ICD means it should fire properly in response to VT or VF (or improperly in response to a benign rhythm) and that creates a safety issue.
    3. Was the ICD or anti-tachycardia device implanted more than three years ago? The mere presence of an ICD that could fire is the relevance, not how long it has been in place.
    4. Has the ICD fired or has the mariner required anti-tachycardia pacing within the last 3 years? If the ICD has not fired, is the diagnosis correct and up to date? Is it functional? It is still in place and could give an inappropriate shock.
    5. Does the mariner’s condition present any confounding risk factors for inappropriate shocks such as atrial fibrillation? Simple sinus tachycardia, which is likely to occur in a high stress situation, exertion, or during any emergency, could also trigger a shock.
    6. Is the mariner’s ejection fraction greater than 40% with a steady or improving trend? The threshold of 40% ejection fraction is a good standard for any cardiac condition.
    7. Does the mariner have a history of any symptomatic or clinically significant heart failure in the past two years? This question is pertinent with respect to the diagnosis of CHF, but as stated previously the presence of an ICD is the issue. If the ejection fraction is <40%, the risk of pathologic dysrhythmia is high. Therefore sudden incapacitation is an inordinate risk to the mariner, his crewmembers and the public.
    8. Does the mariner’s record contain any evidence of significantly reversible ischemia on myocardial perfusion imaging exercise stress testing? This question is pertinent with respect to the presence of reversible ischemia and should be considered on its own merit as potentially disqualifying.
    9. Has the mariner’s exercise capacity been assessed to be greater than or equal to 10 metabolic equivalents (METS)? This question is pertinent with respect to the ability to perform the job duties and could be potentially disqualifying on its own merit. This assesses cardiac function and aerobic capacity, but does not rule out issues with the ICD.
    10. Did the mariner provide a written opinion of the treating cardiologist or electrophysiologist that supports a determination that the mariner is at a low risk for future arrhythmia, adverse cardiac event or sudden incapacitation based upon objective testing and standard evaluation tools? Most physicians are patient advocates. The opinion of the mariner’s cardiologist may be reviewed, but the presence of an ICD and the indications requiring it are still the focus of the review. If the ICD is no longer required and the condition is no longer disqualifying, the mariner may be considered for the issuance of a waiver once the ICD has been removed.
    11. Does the mariner have any other medical condition which may alone, or in combination with an ICD or anti-tachycardia device, affect the mariner's fitness? All medical conditions, whether considered on their own merit or in combination with any other medical condition are pertinent. However, the presence of an ICD alone is the issue.
    12. Is the mariner applying for an original credential, raise-in-grade, or renewal of an existing credential? Any medical condition that is serious enough to be disqualifying should be reviewed. Mariner credentialing should always consider the medical conditions on their own merit.

    In addition, we would like to add one question to the list:

    1. Has the mariner with an ICD in place had any episode of syncope or near syncope?

      If so, this may have been an unrecognized dysrhythmia that may not have been appropriately recognized and shocked.

    Thank you for the opportunity to comment upon these proposed rules. we are available to discuss this issue further at your request.

    Sincerely,

    Karl Auerbach, MD, MS, MBA, FACOEM
    President

    Tony Alleman, MD, MS, MPH, FACOEM
    Co-Chair, ACOEM Transportation Section