Delayed Anaerobic Threshold in Heart Failure Patients With Atrial Fibrillation

Abstract

In HF patients with AF, despite a similar peak (Equation is included in full-text article.)O2 compared with patients with HF and SR, (Equation is included in full-text article.)O2 AT is higher because of a higher HR and a greater HR increase during exercise. One postulated mechanism would be a greater cardiac output increase at the beginning of exercise in HF patients with AF. The delayed AT generates uncertainty about the meaning of a (Equation is included in full-text article.)O2 value at AT in HF patients with AF, because a higher AT is usually associated with better performance and a better prognosis.

Role of comorbidities in heart failure prognosis Part I: Anaemia, iron deficiency, diabetes, atrial fibrillation

“…First, permanent atrial fibrillation is associated with more compromised exercise performance at CPET, expressed by lower values of peak VO 2 , lower value of O 2 pulse and lower workload achieved at peak exercise of about 20% when compared with HFrEF patients in sinus rhythm, but higher values of VO 2 AT. 39 The postponed anaerobic threshold is likely due to different heart rate kinetics during exercise so that the increase at the regimen of exercise is higher in atrial fibrillation patients; consequently cardiac output (CO) increase is anticipated and the anaerobic threshold, which is CO dependent, postponed 40 (Figure 2). Anaerobic threshold is used to confirm the clinical value of CPET information obtained at peak exercise and it has been proposed as a strong alternative to peak VO 2 , being independent of exercise protocol and exercise duration.…”

“…In spite of a significantly lower peak oxygen uptake (VO 2 peak), the atrial fibrillation patient shows an oxygen uptake at anaerobic threshold (AT) similar to the sinus rhythm patient. Modified from Magri et al 40 Figure 3. Kaplan-Meier analysis of study endpoint (composite of cardiovascular (CV) death, urgent heart transplant (HTX) or left ventricular assist device (LVAD) implantation) according to b-blocker equivalent dose at a 10-year follow-up (p < 0.0001).…”

Subtypes and Mechanisms of Hypertrophic Cardiomyopathy Proposed by Machine Learning Algorithms

“…A higher anaerobic threshold in HF patients with AF is reported compared with HF patients with sinus rhythm [ 40 ]. Left atrial (LA) remodeling represents an important substrate for AF [ 41 ], and AF is associated with LA enlargement [ 42 ].…”

Pick Your Threshold

“…HF patients with permanent AF represent a special population since they have a lower performance (lower peak VO2) and a VO2AT that seems to be, on the average, 10% higher than that in sinus rhythm patients. AF patients shows a peculiar behavior of heart rate and cardiac output at the beginning of exercise, with the increased heart rate response likely due to an increased sympathetic drive triggered to maintain cardiac output 16,34,35 . Indeed, as shown by Magrì et al the prognostic meaning of AT in patients with HF and AF is different compared to patients in sinus rhythm 16 .…”