BackgroundBlood pressure is relevant to the diagnosis and management of many medical, cardiovascular and critical diseases. The accuracy of many commonly used noninvasive blood pressure (NIBP) monitors and the accuracy of NIBP measurements in hypo‐ and hypertensive standing horses has not been determined.Hypothesis/ObjectivesThe objective of this study was to investigate the accuracy of an oscillometric BP monitor in standing horses before and during pharmacologically induced hyper‐ and hypotension and to compare results in standing and anesthetized horses.AnimalsEight standing mares from a research herd (SG) and eight anesthetized horses from a hospital population (AG).MethodsProspective experimental and observational studies. Invasive blood pressure (IBP) and NIBP, corrected to heart level, were measured simultaneously. In the SG hyper‐ and hypotension were induced by administration of phenylephrine (3 μg/kg/min IV for 15 minutes) and acepromazine (0.05 mg/kg IV), respectively. In the AG NIBP and IBP were recorded during regular hospital procedures.ResultsThere was a significant correlation between mean NIBP and IBP in standing (R = 0.88, P < .001) and anesthetized horses (R = 0.81, P < .001). The mean bias (lower, upper limit of agreement) was 16.4(−16.1, 48.9) mmHg for mean BP in the SG and 0.5(−22.3, 23.2) mmHg in the AG. The NIBP device was capable of identifying the increase and decrease in BP in all horses, but in the SG significant correlation between NIBP and IBP was only detected for the normotensive phase.Conclusion and Clinical ImportanceWhile the evaluated oscillometric BP device allowed estimation of BP and adequately differentiated marked trends, the accuracy and precision were low in standing horses.

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OBJECTIVE To determine whether hypertension, high sympathetic tone, resting and exercising arrhythmias, and echocardiographic changes consistent with hypertensive cardiomyopathy were associated with equine metabolic syndrome (EMS) in ponies. DESIGN Prospective case-control study. ANIMALS 19 privately owned ponies with a diagnosis of EMS (history of laminitis, body condition score ≥ 7/9, cresty neck score ≥ 3/5, and abnormal oral sugar test result; cases) and 20 healthy control ponies. PROCEDURES Heart rate (HR), noninvasively measured arterial blood pressure (BP), markers of autonomic tone (splenic volume and HR variability), 24-hour and exercising ECGs, and echocardiograms were compared between cases and controls. RESULTS Compared with controls, cases had a higher mean ± SD HR (44.5 ± 7.5 beats/min vs 38.6 ± 6.8 beats/min) and median mean left ventricular wall thickness (2.0 cm vs 1.8 cm). No differences were identified between groups in BP, splenic volume, HR variability, and number of premature complexes in ECGs. Mean wall thickness was correlated with BP (r = 0.54), high-frequency power (r = -0.71), and ratio of low-to high-frequency power (ϕ = 0.66). Relative wall thickness was correlated with serum insulin concentration (r = 0.71). CONCLUSIONS AND CLINICAL RELEVANCE Ponies with EMS had myocardial hypertrophy that was correlated with insulin response to an oral sugar test, sympathetic and parasympathetic tone, and BP. The heterogeneity and limited sample size of this preliminary study should be considered when drawing conclusions. Cardiovascular changes associated with this syndrome deserve further attention.