Acute RIPC of the lower limbs induced a powerful delay in/and reduction in IR induced ventricular arrhythmias, but without evoking the RISK pathway; a late protective phase of RIPC on arrhythmias did not occur.
Models of chronic intermittent hypoxia (CIH), the main feature of obstructive sleep apnoea (OSA), have demonstrated dysregulation of the cardiovascular and respiratory systems resulting in hypertension, cardiac hypertrophy and alterations in the hypoxic ventilatory response (HVR) due to changes in sympathetic and respiratory control by the carotid body. In the UK, treatment of OSA is only offered to patients with an apnoea-hypopnoea index (AHI) >15, we investigated whether mild CIH produced significant pathophysiological changes, which might inform treatment guidelines.Rats were exposed to CIH (6 h(-1), 8 h day(-1), 5 % O(2) nadir) for 2 weeks and then arterial blood pressure (ABP), heart rate (HR) and ventilation were recorded in these and normoxic control rats (N) under Alfaxan anaesthesia, at baseline and in response to Dejours test, graded hypoxia and hypercapnia. Hearts were analysed post-mortem.CIH induced significant increases in baseline ABP (142 ± 5 vs 122 ± 2 mmHg), HR (448 ± 9 vs 412 ± 5 bpm) and cardiac mass (3.5 ± 0.1 vs 2.7 ± 0.1 g kg body mass(-1)) as a result of a selective left ventricular hypertrophy (1.6 ± 0.1 vs 1.3 ± 0.08 g kg body mass(-1); FCSA 464 ± 32 μm(2) vs 314 ± 9 μm(2)). There was no significant difference between N and CIH in baseline respiration or the response to Dejours test, graded hypoxia and hypercapnia.These results demonstrate that mild CIH can induce the significant cardiovascular changes associated with OSA without overt changes in respiratory function. Given evidence that CIH changes carotid body sensory activity, a possible explanation for these results is that there is differential integration of chemoreceptor input with respiratory and cardiac sympathetic outputs.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.