ABSTRACT
BACKGROUND: Paroxysmal atrial fibrillation (pAF) occurs sporadically and can impair athletic performance. Gold standard for diagnosis is surface electrocardiography (ECG), however, this requires AF to be sustained. Implantable loop recorders (ILRs) are routinely used for AF detection in human medicine. While ILR placement has been studied in horses, its AF detection performance is unknown. OBJECTIVES: (I) Validation of ILRs for AF detection in horses. (II) Determining pAF incidence using ILRs and estimate the positive predictive value (PPV). STUDY DESIGN: (I) Experimental study; (II) Longitudinal observational study. METHODS: (I) Implantation of ILRs in 15 horses with AF and 13 horses in sinus rhythm. Holter ECGs were recorded at: 1, 4, 8, 12 and 16 weeks of AF. The ILR ECGs were compared with surface ECGs to assess diagnostic sensitivity and specificity. (II) Eighty horses (43 Warmbloods, 37 Standardbreds) with ILRs were monitored for 367 days [IQR 208-621]. RESULTS: (I) ILRs detected AF on all recording days, in horses with AF, with a sensitivity of 66.1% (95% CI: 65.8-66.5) and a specificity of 99.99% (95% CI: 99.97-99.99). The sensitivity remained consistent across all time points. (II) The incidence of pAF was 6.3% (5/80). In horses with pAF, the PPV ranged from 8% to 87%. Increased body condition score (BCS > 6/9) was associated with an increased number of false positive episodes (p = 0.005). MAIN LIMITATIONS: (I) Horses were stabled during the ECG recordings, and AF was induced, rather than naturally occurring pAF. (II) Integrated algorithm in this ILR is optimised for AF detection in humans using remote monitors. Additionally, sensing is affected by motion artefacts. CONCLUSION: The ILR reliably detected AF in resting horses, particularly in horses with normal BCS (6/9). The ILR proved useful to detect pAF and is recommended alongside Holter monitoring for diagnostic workup of horses with suspected pAF.
ABSTRACT
BACKGROUND: Neutrophil gelatinase-associated lipocalin (NGAL) is produced in response to inflammation in horses, but it has not yet been investigated as a biomarker in horses with the abdominal disease. OBJECTIVES: To investigate NGAL in serum and peritoneal fluid in horses with the abdominal disease. STUDY DESIGN: Retrospective clinical study. METHODS: Data from medical records of 270 horses admitted with acute abdominal disease (simple obstructions [n = 43], strangulating obstructions [n = 104], inflammatory abdominal disease [n = 99], non-strangulating intestinal infarction [NSII, n = 24]) and 9 healthy control horses were reviewed, and serum and peritoneal fluid samples were retrieved from a biobank. NGAL was measured in serum and peritoneal fluid by ELISA. Differences in NGAL concentrations between groups were assessed. RESULTS: Healthy horses had low serum and peritoneal fluid concentrations of NGAL (median = 21.0 and 9.5 µg/L, respectively). Neither serum nor peritoneal fluid NGAL concentrations (median serum, peritoneal fluid) differed between healthy horses and horses with simple (28.1 µg/L, 13.0 µg/L) and strangulating intestinal obstructions (34.7 µg/L, 38.4 µg/L). Horses with NSII (308.0 µg/L, 2163.0 µg/L) and inflammatory abdominal disease (171.1 µg/L, 314.1 µg/L) had higher serum and peritoneal fluid concentrations of NGAL than the other groups (p < 0.001). Peritoneal fluid NGAL concentrations in horses with NSII were higher than in horses with inflammatory abdominal disease (p = 0.03). MAIN LIMITATIONS: Retrospective study design; small group of control horses. CONCLUSIONS: NGAL is a marker of inflammation in horses with the abdominal disease. The high peritoneal fluid concentration of NGAL in horses with NSII compared to all other groups may render NGAL useful for identifying this condition, which is otherwise difficult to differentiate from other types of peritonitis. Thereby, NGAL may potentially facilitate timely surgical intervention in this group of patients. The results of this study must be evaluated in larger, and preferably prospective, studies to obtain a more comprehensive evaluation of the diagnostic utility of NGAL.
CONTEXTO: Lipocalina associada à gelatinase de neutrófilos (NGAL) é produzida em resposta à inflamação em equinos, mas ainda não foi investigada como biomarcador de equinos com doenças abdominais. OBJETIVOS: Investigar a NGAL no soro e líquido peritoneal (LP) de equinos com doenças abdominais. DELINEAMENTO DO ESTUDO: Estudo retrospectivo. METODOLOGIA: Informação de prontuários médicos de 270 equinos com doença abdominal (obstrução simples [n = 43], obstrução estrangulante [n = 104], doença abdominal inflamatória [n = 99], lesão de infarto não estrangulante [NSII, n = 24]) e nove equinos saudáveis como controle foram revisados, e o soro e LP foram obtidos de um biobank. NGAL foi mensurado no soro e LP através de ELISA. Diferenças na concentração de NGAL entre os grupos foi avaliada. RESULTADOS: Cavalos saudáveis tiveram concentração de NGAL baixas no soro e no LP (mediana = 21.0 e 9.5 µg/L, respectivamente). A concentração de NGAL no soro e no LP não diferiram entre cavalos saudáveis e cavalos com obstrução simples (28.1,13.0) e obstrução estrangulante (34.7, 38.4). Cavalos com NSII (308.0, 2163.0) e doença abdominal inflamatória (171.1314.1) tiveram concentrações mais altas de NGAL no soro e LP quando comparados aos outros grupos (p < 0.001). A concentração de NGAL no LP em cavalos com NSII foi mais alta do que em cavalos com doença abdominal inflamatória (p = 0.03). PRINCIPAIS LIMITAÇÕES: Delineamento de estudo retrospectivo e pequeno grupo de equinos controle. CONCLUSÕES: NGAL é um marcador de inflamação em cavalos com doença abdominal. A concentração alta de NGAL no LP de cavalos com NSII comparado com os outros grupos indica que NGAL pode ser útil em identificar essa condição, o que é usualmente difícil de diferenciar de outros tipos de peritonite. Contudo, NGAL tem o potencial de facilitar a decisão rápida da necessidade de intervenção cirúrgica nesse grupo de pacientes. Os resultados deste estudo devem ser avaliados em uma população maior (e preferencialmente prospectiva) para obter uma melhor avaliação compreensiva da utilidade diagnóstica do NGAL.
