Assessment of cardiovascular functioning following sport-related concussion: A physiological perspective.

There is still much uncertainty surrounding the approach to diagnosing and managing a sport-related concussion (SRC). Neurobiological recovery may extend beyond clinical recovery following SRC, highlighting the need for objective physiological parameters to guide diagnosis and management. With an increased understanding of the connection between the heart and the brain, the utility of assessing cardiovascular functioning following SRC has gained attention. As such, this review focuses on the assessment of cardiovascular parameters in the context of SRC. Although conflicting results have been reported, decreased heart rate variability, blood pressure variability, and systolic (ejection) time, in addition to increased spontaneous baroreflex sensitivity and magnitude of atrial contraction have been shown in acute SRC. We propose that these findings result from the neurometabolic cascade triggered by a concussion and represent alterations in myocardial calcium handling, autonomic dysfunction, and an exaggerated compensatory response that attempts to maintain homeostasis following a SRC. Assessment of the cardiovascular system has the potential to assist in diagnosing and managing SRC, contributing to a more comprehensive and multimodal assessment strategy.

Catheter-Induced Postextrasystolic Potentiation in the Assessment of Severity of Low-Gradient Aortic Valve Stenosis.

BACKGROUND: Deciphering which patients with low-gradient aortic valve disease have severe stenosis can be difficult. We aimed to correlate the postextrasystolic potentiation (PESP) with dobutamine stress echocardiography and multidetector computed tomography in patients with low-gradient aortic valve stenosis. METHODS: Patients with an aortic valve area ≤1 cm2 and a mean gradient <40 mm Hg were included. Aortic valve stenosis severity was assessed by a core lab with dobutamine stress echocardiography, followed by a multidetector computed tomography aortic valve score if indeterminate. A premature ventricular contraction was induced by intentional catheter contact with the myocardium within the left ventricle. PESP was calculated as a percent change of pre-to-post mean gradient. Multidetector computed tomography was used to measure the aortic valve calcification score, and subsequently, aortic valve calcification density. RESULTS: Twenty-eight patients (age, 77±10 years; 19 female) were included. Dobutamine stress echocardiography increased mean gradient from baseline of 25±7 mm Hg to 36±11 mm Hg; pre-premature ventricular contraction mean gradient was 25±7 mm Hg and increased to post-premature ventricular contraction mean gradient of 32±10 mm Hg, representing a PESP of 24±11%. A ≥20% in PESP resulted in 100% sensitivity, 77% specificity, 83% positive predictive value, and 100% negative predictive value for diagnosing severe aortic valve stenosis. There was a significant correlation between PESP and projected aortic valve area and aortic valve calcification density (R=-0.64, P=0.0003; R=0.057, P=0.014, respectively). CONCLUSIONS: In patients with low-gradient aortic valve stenosis, catheter-induced premature ventricular contractions during cardiac catheterization causing ≥20% PESP has a 100% sensitivity for severe aortic valve stenosis. Validation of this 20% cutoff in larger groups with correlation to clinical end points is required.