Cardiac Enlargement in US Firefighters: Prevalence Estimates by Echocardiography, Cardiac Magnetic Resonance and Autopsies

Abstract

Background: Cardiovascular Disease (CVD) accounts for 45% of on-duty deaths in US fire service; cardiac enlargement is common among US firefighters; and plays a major role in firefighter Sudden Cardiac Death (SCD). Objective: To estimate the prevalence of cardiac enlargement in US Firefighters by autopsies, echocardiography (ECHO) and Cardiac Magnetic Resonance (CMR). Methods: In the present cross-sectional study, the prevalence of Left Ventricular Hypertrophy (LVH)/ cardiomegaly was a) estimated non-invasively among active career firefighters and b) examined by reviewing autopsies of firefighters who suffered a non-cardiac, on-duty fatality. Left ventricular mass (LVM) among active career firefighters was assessed by ECHO and CMR, and normalized (indexed) for body surface area (BSA) and height. Autopsy estimates were based on cardiac weights and other forensic parameters. Results: LVH prevalence estimates among active career firefighters presented a range from 3.3% to 32.8% among ECHO; and 0.0% to 5.3% among CMR criteria. LVH was present in 17.5% and 0.4% of the active firefighters as defined by LVM indexed to height 1.7 (by ECHO and CMR, respectively). LVM indexed to BSA as measured by CMR indicated zero prevalence of LVH. Among non-cardiac traumatic autopsies, prevalence estimates of cardiomegaly and LVH were 39.5% (95% CI 33.7-45.3) and 45.4% (95% CI 39.5-51.4) respectively, even after adjustment for age and BMI. Conclusions: The prevalence of cardiac enlargement varied widely depending on the imaging assessment, the cutoffs and the normalization techniques. For autopsy data, BMI was a major determinant of heart weight. Future CVD-outcome based studies are needed to provide evidence for the most accurate clinical cutoffs, while standardization of autopsies is needed across protocols and jurisdictions.

Bradycardia in Athletes: Does the Type of Sport Make Any Difference? – A Systematic Review

“…[2][3][4][5][6] On the other hand, the autonomic hypothesis has been refuted in some other studies, suggesting that the main adaptation responsible for athlete's bradycardia is the intrinsic reduction of the sinus node firing frequency. [7][8][9][10] Despite that, since different training models and professions may result in different forms of cardiovascular overload, and considering that physiological chronic adaptations induced by physical training are specific to the type of stimuli offered during successive training sessions, [11][12][13] it is plausible to hypothesize that the mechanisms responsible for bradycardia are dependent on the athletic modality. In fact, functional and structural differences have been reported in hearts of athletes involved in different athletic modalities.…”

Avaliação da função autonômica cardíaca e da sobrecarga cardiovascular de bombeiros militares durante turno de serviço operacional

“…Assim, no cenário acima descrito, das elevadas exigências profissionais a que bombeiros são expostos (SMITH et al, 1996;VON HEIMBURG;RASMUSSEN;MEDBO, 2006) e dos riscos cardiovasculares associados (SMITH et al, 2016a), um foco importante da pesquisa deve ser a identificação precoce de indivíduos mais suscetíveis, uma vez que o aumento de risco cardiovascular não ocorre de forma aleatória, nem quanto aos sujeitos, ao tipo de atividade desempenhada, à hora do dia ou à estação do ano (KALES et al, 2003;MBANU et al, 2007, SOTERIADES et al, 2011. Sabe-se que a maior suscetibilidade tem sido associada a atividades de efetivo combate a incêndios, a sujeitos portadores de condições clínicas diversas como obesidade, hipertensão arterial, cardiomegalia e baixa aptidão cardiorrespiratória (SOTERIADES et al, 2001;SMITH et al, 2016a;KORRE et al, 2016a;DURAND et al, 2011;BAUR et al, 2011;BAUR et al, 2012). Portanto, a identificação precoce de sujeitos mais suscetíveis pode subsidiar adaptações laborais, como mudança de…”

“…Dentro do contexto de suscetibilidade, há que se considerar, ainda, o potencial efeito da disfunção autonômica cardíaca no possível desencadeamento de arritmias graves e/ou morte súbita cardíaca (JUNQUEIRA JÚNIOR, 2012;SHEN et al, 2014;FUKUDA et al, 2015). Nesse sentido, a avaliação da FAC ganha importância, pois sua disfunção pode ser um sinal inicial de maior susceptibilidade, especialmente quando se considera o elevado percentual de cardiomegalia/hipertrofia ventricular esquerda entre bombeiros, que reconhecidamente se associa com maior risco de arritmias (KORRE et al, 2016a;KORRE et al, 2016b). A título de ilustração, foram apresentadas as Figuras 14-18 na seção de resultados.…”

“…na autópsia(GOLDBERG, et al, 2001). Estudo recente também evidenciou proporções de cardiomegalia entre bombeiros que faleceram por causas não cardíacas variando entre 33-56% entre diferentes faixas etárias ou categorias de IMC, quando se usou o ponto de corte de parede ventricular >=1,2 cm(KORRE et al, 2016a).…”