Thibaut Guiraud - Academia.edu (original) (raw)
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Università degli Studi di Milano - State University of Milan (Italy)
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Papers by Thibaut Guiraud
PLoS ONE, 2014
Background: The exact pathophysiology of Tako-Tsubo cardiomyopathy (TTC) remains unknown but a ro... more Background: The exact pathophysiology of Tako-Tsubo cardiomyopathy (TTC) remains unknown but a role for sympathetic hyperactivity has been suggested. Up to now, no direct evidence of sympathetic nerve hyperactivity has been established nor involvement of sympathetic baroreflex identified. The aim of our study was to determine, by direct sympathetic nerve activity (SNS) recording if sympathetic nervous system activity is increased and spontaneous baroreflex control of sympathetic activity reduced in patients with TTC.
Medicine & Science in Sports & Exercise, 2013
Purpose: Autonomic dysfunction including sympathetic activation and vagal withdrawal has been rep... more Purpose: Autonomic dysfunction including sympathetic activation and vagal withdrawal has been reported in patients with chronic heart failure (CHF). We tested the hypotheses that high-intensity interval exercise (HIIE) in CHF patients would enhance vagal modulation and thus decrease arrhythmic events. Methods: Eighteen CHF patients underwent a baseline assessment (CON) and were then randomized to a single session of HIIE and to an isocaloric moderate-intensity continuous exercise (MICE). We evaluated the HR, HR variability parameters, and arrhythmic events by 24-h Holter ECG recordings after HIIE, MICE, and CON sessions. Results: We found that HR was significantly decreased after HIIE (68 T 3 bpm, P G 0.01) when compared with CON and MICE values (71.1 T 2 and 69 T 3 bpm, respectively). HIIE led to a significant increase in normalized high-frequency power (35.95% T 2.83% vs 31.56% T 1.93% and 24.61% T 2.62% for CON and MICE, respectively, P G 0.01). Both exercise conditions were associated with an increase in VLF AQ1 power comparative to CON. After HIIE, premature ventricular contractions were significantly decreased (531 T 338 vs 1007 T 693 and 1671 T 1604 for CON and MICE, respectively, P G 0.01). An association was found between the changes in premature ventricular contraction and the changes in low-frequency/high-frequency ratio (r = 0.66, P G 0.01) in patients exposed to HIIE. Conclusion: We demonstrate that a single session of HIIE improves autonomic profile of CHF patients, leading to significant reductions of HR and arrhythmic events in a 24-h posttraining period. Cardioprotective effects of HIIE in CHF patients need to be confirmed in a larger study population and on a long-term basis.
PLoS ONE, 2014
Background: The exact pathophysiology of Tako-Tsubo cardiomyopathy (TTC) remains unknown but a ro... more Background: The exact pathophysiology of Tako-Tsubo cardiomyopathy (TTC) remains unknown but a role for sympathetic hyperactivity has been suggested. Up to now, no direct evidence of sympathetic nerve hyperactivity has been established nor involvement of sympathetic baroreflex identified. The aim of our study was to determine, by direct sympathetic nerve activity (SNS) recording if sympathetic nervous system activity is increased and spontaneous baroreflex control of sympathetic activity reduced in patients with TTC.
Medicine & Science in Sports & Exercise, 2013
Purpose: Autonomic dysfunction including sympathetic activation and vagal withdrawal has been rep... more Purpose: Autonomic dysfunction including sympathetic activation and vagal withdrawal has been reported in patients with chronic heart failure (CHF). We tested the hypotheses that high-intensity interval exercise (HIIE) in CHF patients would enhance vagal modulation and thus decrease arrhythmic events. Methods: Eighteen CHF patients underwent a baseline assessment (CON) and were then randomized to a single session of HIIE and to an isocaloric moderate-intensity continuous exercise (MICE). We evaluated the HR, HR variability parameters, and arrhythmic events by 24-h Holter ECG recordings after HIIE, MICE, and CON sessions. Results: We found that HR was significantly decreased after HIIE (68 T 3 bpm, P G 0.01) when compared with CON and MICE values (71.1 T 2 and 69 T 3 bpm, respectively). HIIE led to a significant increase in normalized high-frequency power (35.95% T 2.83% vs 31.56% T 1.93% and 24.61% T 2.62% for CON and MICE, respectively, P G 0.01). Both exercise conditions were associated with an increase in VLF AQ1 power comparative to CON. After HIIE, premature ventricular contractions were significantly decreased (531 T 338 vs 1007 T 693 and 1671 T 1604 for CON and MICE, respectively, P G 0.01). An association was found between the changes in premature ventricular contraction and the changes in low-frequency/high-frequency ratio (r = 0.66, P G 0.01) in patients exposed to HIIE. Conclusion: We demonstrate that a single session of HIIE improves autonomic profile of CHF patients, leading to significant reductions of HR and arrhythmic events in a 24-h posttraining period. Cardioprotective effects of HIIE in CHF patients need to be confirmed in a larger study population and on a long-term basis.