Afterload reduction after non-invasive vagus nerve stimulation in acute heart failure
Michiaki Nagai1, Keigo Dote1, Masaya Kato1
1Department of Cardiology, Hiroshima City Asa Hospital, Hiroshima, Japan.
Insights
Transcutaneous vagus nerve stimulation (tVNS) significantly reduced central blood pressure and heart rate in elderly patients with acute heart failure. This non-invasive low-level transcutaneous electrical stimulation (LLTS) offers a safe method for acute afterload reduction in heart failure patients.
Area of Science:
- Cardiology
- Neurology
- Medical Devices
Background:
- Central blood pressure (BP) is a key indicator of left ventricular (LV) afterload.
- Reducing central BP can prevent heart failure (HF) decompensation.
- Non-invasive transcutaneous vagus nerve stimulation (tVNS) has shown potential in improving cardiac function in HF patients.
Purpose of the Study:
- To investigate the relationship between active tVNS and central BP reduction in patients with acute heart failure (AHF).
- To evaluate the safety and efficacy of non-invasive low-level transcutaneous electrical stimulation (LLTS) for afterload reduction in AHF.
Main Methods:
- A randomized controlled trial involving 22 elderly AHF patients.
- Patients received daily 1-hour sessions of LLTS (20 Hz, 1 mA) for 5 days, with active tVNS applied to the tragus or sham stimulation to the earlobe.
- Central aortic systolic pressure (CASP), brachial systolic BP (SBP), diastolic BP (DBP), and heart rate (HR) were measured noninvasively before and after stimulation.
Main Results:
- Active tVNS significantly decreased CASP, SBP, DBP, and HR in the active group (p < 0.05).
- Sham stimulation led to significant increases in CASP, SBP, DBP, and HR (p < 0.05).
- Significant differences in all measured parameters were observed between the active and sham groups (p < 0.01), with no device-related side effects.
Conclusions:
- Left tragus tVNS effectively reduces acute afterload in elderly AHF patients.
- Non-invasive LLTS is a potentially useful and safe therapeutic option for reducing afterload in AHF.
Introduction:
While central blood pressure (BP) has been recognized as a major indicator of left ventricular (LV) afterload, the reduction of central pressure decreases LV afterload and may prevent heart failure (HF) decompensation. Non-invasive transcutaneous vagus nerve stimulation (tVNS) was shown to improve cardiac function in HF patients. In this study, the relationship between active tVNS and reduction of central BP was investigated in patients with acute HF (AHF).
Methods:
The 22 patients hospitalized for AHF after initial stabilization (median 80 yrs, males 60%) were randomly assigned to active or sham group. For 1 h daily over 5 days, low-level transcutaneous electrical stimulation (LLTS) (20 Hz, 1 mA) was performed after attaching an ear clip to the tragus (active group) or the earlobe (sham control group). Before and after stimulation, central aortic systolic pressure (CASP), brachial systolic BP (SBP), diastolic BP (DBP) as well as heart rate (HR) were noninvasively measured.
Results:
No significant differences in baseline characteristics were observed between the active and sham groups. In the active group, CASP, SBP, DBP, and HR each decreased significantly after stimulation (all p < 0.05), whereas in the sham group, CASP, SBP, DBP, and HR each increased significantly after stimulation (all p < 0.05). All the changes in CASP, SBP, DBP and HR before and after stimulation were also significantly different between active and sham groups (all p < 0.01). There were no device-related side effects.
Conclusion:
In this study, the left tragus tVNS resulted in an acute afterload reduction in the elderly AHF patients. Non-invasive LLTS may be useful and safe for reducing afterload in AHF.
Clinical Trial Registration:
ClinicalTrials.gov, identifier UMIN000044121.
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