RESUMO
Background: Exercise therapy for cardiovascular disease (CVD) is mainly evaluated based on the heart rate (HR) or Borg scale. However, these indices can be unreliable depending on the patient's medication or their subjective decisions; thus, alternative methods are required for easier and safer implementation of aerobic exercise. Here, we examined whether real-time analysis of HR variability (HRV) can help maintain exercise intensity at the ventilatory threshold (VT) during exercise. Methods: Twenty-eight patients with CVD treated at Keio University Hospital between August 2018 and March 2020 were enrolled. Initially, oxygen uptake (VO2) and HR at the VT were determined using the cardiopulmonary exercise test. Patients then performed aerobic exercise on a stationary bicycle for 30 min while a parameter of HRV, the high-frequency (HF) component, was monitored in real time using an electrocardiograph. The work rate during exercise was adjusted every 2 min to maintain the HF range between 5 and 10. The VO2 and HR values, recorded every 2 min during exercise, were compared with those at VT. The Bland-Altman method was used to confirm similarity. Results: VO2 and HR during exercise were closely correlated with those at VT (e.g., 19 min after exercise initiation; VO2: r = 0.647, HR: r = 0.534). The Bland-Altman plot revealed no bias between the mean values (e.g., 19 min; VO2: -0.22 mL/kg/min; HR: -0.07/min). Conclusion: Real-time HRV analysis with electrocardiograph alone during exercise can provide continuous and non-invasive exercise intensity measurements at VT, promoting safer and effective exercise strategies.
RESUMO
Periprocedural bleeding is associated with an increased risk of mortality during percutaneous coronary intervention (PCI), especially in patients with severe chronic renal insufficiency. Therefore, trans-radial intervention (TRI) should be considered in these patients; however, PCI operators usually avoid this approach because of the risk of radial artery occlusion. We aimed to investigate the associations of TRI and in-hospital complications in these patients. This study included 306 consecutive patients with severe chronic renal insufficiency and/or on dialysis who underwent PCI. Patients were prospectively enrolled and divided according to the access site into TRI group and trans-femoral intervention group. Severe renal insufficiency was defined as estimated glomerular filtration rate < 30 mL/min/1.73 m2. Radial access was limited to the opposite side of the arteriovenous fistula in patients on hemodialysis. The primary study endpoint was the composite of in-hospital bleeding complications and death. TRI benefit was evaluated by inverse probability treatment weighted analysis. TRI was performed in 112 (37.3%) patients. TRI group included older patients with significantly lower rates of diabetes mellitus, dialysis, and three-vessel disease. Crossover to the other approach occurred only in TRI group (2.6%). The primary endpoint was significantly lower in TRI group (11.5% vs. 2.6%, P = 0.006). After an inverse probability treatment weighted analysis, TRI was an independent prognostic factor for a decrease in the primary endpoint (OR 0.19; 95% CI 0.051-0.73; P = 0.015). Radial artery occlusion occurred in three patients on dialysis (9.1%). TRI may determine better in-hospital outcomes in patients with severe chronic renal insufficiency and/or on dialysis.