Welcome to occupational cardiology, at present more questions than answers

This editorial refers to ‘Cardiovascular risk in high-hazard occupations: the role of occupational cardiology’, by I.T. Parsons et al., pp. 702–713. In the present issue of the European Journal of Preventive Cardiology, a new emerging field of Cardiology is presented, the Occupational Cardiology.1 The latter deals with so-called ‘high-hazard’ occupations in which the presence of a Cardiovascular disease may hamper the working capacity of a subject. Accordingly, extreme occupations such as Pilot and Aircrew, Astronauts, Divers, High-Altitude Workers, Emergency Workers, and Military Personal are considered. Clearly, many other occupations may be considered as high hazard as high hazard may be only a percentage of the working time. Just for example doctors without frontiers or health personal involved in the treatment of coronavirus disease 2019 patients. Apparently, there is not a bottom line that comprehends all these working conditions being the physiological contest characterized by different ambient conditions such as hypobaric hypoxia, very low or high ambient temperature, atmospheric pressure changes or risk environmental due to natural or human-generated conditions. Clearly, it is not easy to imagine a cardiology expert in all of them. However, the risk imposed to the cardiovascular system may be, at end, similar being associated to an increased sympathetic activity which may both be the cause of cardiovascular diseases or the trigger event of acute cardiovascular event. The common line which comprehends all the work is that they are characterized by both high hazard conditions and increase in sympathetic activity. High hazard means also activity that is difficult to interrupt immediately in case of need and which are typically held far away from an emergency room. Consequently, specific attention should be dedicated to these workers to minimize the risk of a cardiovascular event. The questions are how and how often perform such preventive interventions. The first-line evaluation is based on history, basic laboratory data, physical examination, and electrocardiogram (ECG). There are no controversies about this, but which is the second step for higher-level evaluation is much less defined. Indeed, several cardiac imaging techniques, such as transthoracic echocardiography, carotid artery echo-Doppler evaluation, cardiac magnetic resonance, exercise test, or computer tomography scan of the coronary arteries alone or in combination have been proposed. However, the economic burden as well as the exposure to radiation and contrast media for the subject and the entire community represent an evident limit for the wide spread use of some of these techniques at a screening level. Hence, the ideal technique should be cheap, easy to perform and to repeat, allow a holistic evaluation and free of side effects. Albeit such technique does not exist, the cardiopulmonary exercise test seems to us the method that covers all these different needs. Indeed, cardiopulmonary exercise test is at present the best tool to define exercise performance, causes of exercise limitation as well as the surgical risk and it is the only holistic test we have to assess the several body functions and how they interact between each other.2,3 Specifically, cardiopulmonary exercise test allows evaluating cardiovascular performance, oxygen delivery to the muscle, oxygen utilization by the muscle, efficiency of ventilation, sympathetic, and parasympathetic tone balance.4 Of note, the sympathetic/parasympathetic balance can be assessed during a cardiopulmonary exercise test not only by the heart rate behaviour but also by the end tidal CO2 pressure during the isocapnic buffering period which depends on chemoreflex activation (Figure 1).5 Unfortunately, the role of cardiopulmonary exercise test has not been underlined in the article by Ian Parson et al.1 Cardiopulmonary exercise test parameters which depend on sympathetic/parasympathetic balance and chemoreflex activation. Source: https://www.facebook.com/AeronauticaMilitareOfficialPage/photos/?ref=page_internal Albeit this depends on type of high hazard work and worker conditions the present is, in our opinion, a no-answer question. Indeed, how often repeat a test in a given subject in the absence of new symptoms or intercurrent events is in the majority of cases left to the experience or un-experience of the referring doctor. Consequently, this ignorance needs to be underlined at least. Another question which may be crucial for occupational cardiology experts is, in case of a cardiovascular event, the definition of role of the operating conditions on the event and its consequences. Once more an acute cardiovascular event can occur in all circumstances, but it is difficult to define whether an event during a high-hazard work is due to this type of work or if it is aggravated by this type of work. Frequently more than one risk factor is present making a legal controversy difficult and based on undefinable events. For example, an acute cardiovascular event in a high-altitude miner in Chile who smoke and is hypertensive and possibly with high cholesterol level is due to the working condition, i.e. hypobaric hypoxia, or to the other risk factors? And what is the relative importance of hypobaric hypoxia? Honestly, we do not know. In brief, welcome to occupational cardiology, at present more questions than answers. Conflict of interest: none declared. The opinions expressed in this article are not necessarily those of the Editors of the European Journal of Preventive Cardiology or of the European Society of Cardiology.