Impaired parasympathetic function in long-COVID postural orthostatic tachycardia syndrome – a case-control study

Abstract Purpose Eighty percent of patients infected by SARS-CoV-2 report persistence of one symptom beyond the 4-week convalescent period. Those with orthostatic tachycardia and orthostatic symptoms mimicking postural tachycardia syndrome, they are defined as Long-COVID POTS [LCP]. This case-control study investigated potential differences in autonomic cardiovascular regulation between LCP patients and healthy controls. Methods Thirteen LCP and 16 healthy controls, all female subjects, were studied without medications. Continuous blood pressure and ECG were recorded during orthostatic stress test, respiratory sinus arrhythmia, and Valsalva maneuver. Time domain and power spectral analysis of heart rate [HR] and systolic blood pressure [SBP] variability were computed characterizing cardiac autonomic control and sympathetic peripheral vasoconstriction. Results LCP had higher deltaHR (+ 40 ± 6 vs. + 21 ± 3 bpm, p = 0.004) and deltaSBP (+ 8 ± 4 vs. -1 ± 2 mmHg, p = 0.04) upon standing; 47% had impaired Valsalva maneuver ratio compared with 6.2% in controls (p = 0.01). Spectral analysis revealed that LCP had lower RMSSD (32.1 ± 4.6 vs. 48.9 ± 6.8 ms, p = 0.04) and HFRRI, both in absolute (349 ± 105 vs. 851 ± 253ms2, p = 0.03) and normalized units (32 ± 4 vs. 46 ± 4 n.u., p = 0.02). LFSBP was similar between groups. Conclusions LCP have reduced cardiovagal modulation, but normal sympathetic cardiac and vasoconstrictive functions. Impaired parasympathetic function may contribute to the pathogenesis of Long-COVID POTS syndrome

Blood Pressure Management in Afferent Baroreflex Failure JACC Review Topic of the Week

Afferent baroreflex failure is most often due to damage of the carotid sinus nerve because of neck surgery or radiation. The clinical picture is characterized by extreme blood pressure lability with severe hypertensive crises, hypotensive episodes, and orthostatic hypotension, making it the most difficult form of hypertension to manage. There is little evidence-based data to guide treatment. Recommendations rely on understanding the underlying pathophysiology, relevant clinical pharmacology, and anecdotal experience. The goal of treatment should be improving quality of life rather than normalization of blood pressure, which is rarely achievable. Long-acting central sympatholytic drugs are the mainstay of treatment, used at the lowest doses that prevent the largest hypertensive surges. Short-acting clonidine should be avoided because of rebound hypertension, but can be added to control residual hypertensive episodes, often triggered by mental stress or exertion. Hypotensive episodes can be managed with countermeasures and short-acting pressor agents if necessary. (C) 2019 by the American College of Cardiology Foundation