To verify the efficacy of transcutaneous vagus nerve stimulation (tVNS) on and autonomic balance in patients with chronic heart failure and reduced (HFrEF) or mildly reduced (HFmrEF) left ventricular ejection fraction. The study hypothesis is that tVNS increases baroreflex gain, with consequent benefits on sympathovagal balance (at short- and mid-term), and on quality of life and bio-humoral parameters (at mid-term).
Pilot phase: comparing the effects of right- (10-minute) vs. left-sided tVNS (10-minute) on BRS and heart rate variability (HRV) in a subset of patients. Short-term phase: comparing the effects of active- (10-minute) vs. sham-tVNS (10-minute) on BRS, HRV, and sympathetic nerve activity. Mid-term phase: comparing the effects of active- (4-week) vs- sham-tVNS (4-week) on BRS, HRV, biomarkers, exercise performance, and cardiac function.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
24
As for the short-term phase, the ear clip of the "Parasym" device (Parasym, London, United Kingdom), containing the stimulation electrode, will be positioned at the level of the patient's tragus, and a 10-minute stimulation will be initiated with a pulse width of 200 μs, a frequency of 30 Hz, and an intensity of one mA lower than the patient's sensitivity threshold. As fort he mid-term phase, a device will be given to the patient, which will be instructed to position the ear clip of the device at the level of the tragus and to set stimulation parameters as established in the laboratory (see above). Each patient will be asked to undergo at least one hour daily stimulation for a period of 4 weeks, reporting on a diary the timing and details of the each session.
As for the short-term phase, the ear clip of the "Parasym" device (Parasym, London, United Kingdom), containing the stimulation electrode, will be positioned at the level of the patient's tragus for 10-minute but no current will be delivered. As fort he mid-term phase, a device (configured to withhold power delivery) will be given to the patient, which will be instructed to position the ear clip of the device at the level of the tragus and to set stimulation parameters as established in the laboratory (see above). Each patient will be asked to undergo at least one hour daily stimulation for a period of 4 weeks, reporting on a diary the timing and details of the each session.
Michele Emdin
Pisa, Pi, Italy
Mean change in baroreflex gain (ms/mmHg)
Barorefex gain will be calculated calculated as the ratio between the standard deviation of RR intervals (ms) and systolic blood pressure (mmHg)
Time frame: 10 minutes (short-term effect)
Mean change in baroreflex gain (ms/mmHg)
Barorefex gain will be calculated calculated as the ratio between the standard deviation of RR intervals (ms) and systolic blood pressure (mmHg)
Time frame: 4 weeks (mid-term effect)
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