Surgical closure of arteriovenous fistula reduces left ventricular diameter and mass in kidney transplant recipients. Increases in blood pressure and total peripheral resistance induced by temporary fistula occlusion are the best predictors of these morphological changes.

Our results did not support the opinion that headache experienced by stage 1-2 hypertensives was generally caused by simultaneous elevation in blood pressure. The direct mechanisms of headache in hypertension, as well as the relation between increments in blood pressure above 180/110 mmHg and headache, need further investigations.

Background-Reappearance of low-frequency (LF) (Ϯ0.10 Hz) oscillations in RR interval (RR) after cardiac transplantation is indicative of sympathetic efferent reinnervation. We hypothesized that restored LF oscillations in RR in heart transplant recipients (HTRs) are linked to oscillations in muscle sympathetic nerve traffic (MSNA). Methods and Results-RR, RR variability, and MSNA were recorded 5Ϯ2 months (nϭ7, short-term HTRs) and 138Ϯ8 months (nϭ7, long-term HTRs) after heart transplantation and compared with matched hypertensive patients (nϭ7). A coherence function determined the coupling between LF oscillations in MSNA and RR. RR variance did not differ between short-term and long-term HTRs. However, LF variability was only 1Ϯ0.5 ms 2 in the short-term HTRs but was 15Ϯ8 ms 2 in the long-term HTRs (PϽ0.05). Normalized LF variability was also higher in the long-term HTRs (40Ϯ14 normalized unites) versus the short-term HTRs (6Ϯ3 normalized united, PϽ0.05) but did not differ from the LF variability of the hypertensive patients. Long-term HTRs were taking less cyclosporine (PϽ0.01) but had higher MSNA than the short-term HTRs (62Ϯ7 versus 31Ϯ7 burst/min, respectively, PϽ0.05). Coherence between LF oscillations in MSNA and RR was similar in the long-term HTRs (0.59Ϯ0.11) and the hypertensive patients (0.60Ϯ0.07) and was 3-fold greater than in the short-term HTRs (0.20Ϯ0.06, PϽ0.05). Conclusions-Cardiac reinnervation after long-term heart transplantation is characterized by a restoration of the coherence between LF oscillations in RR and MSNA. Higher MSNA in long-term than in short-term HTRs suggests that time elapsed after cardiac transplantation may be a major determinant of sympathetic excitation in heart transplant recipients.

Arterial baroreceptor activation and increased arterial baroreflex sensitivity decrease heart rate during AVF occlusion. In addition, our study is the first to demonstrate that arterial baroreflex activation decreases sympathetic nerve traffic during the Nicoladoni-Branham sign.

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