The Effect of Auricular Vagus Nerve Stimulation on Heart Rate Variability

Abstract

Autonomic nervous system (ANS) is a structure which operates involuntarily and controls vital functions. Vagus Nerve Stimulation (VNS) is a novel treatment method focused on addressing ANS dysfunctions in cases of imbalance between sympathetic and parasympathetic nervous system activation. With VNS, parasympathetic activity (PA) increases while sympathetic activity (SA) decreases, affecting cardiovascular parameters. Heart rate fluctuates with each beat, reflecting the influence of PA and SA signals on the sinoatrial node. Research indicates that as individuals age, PA in the heart diminishes, while SA tone increases. When heart rate variability (HRV) and respiratory sinus arrhythmia are used to assess vagal tone, reduced PA control over the heart is revealed. This shift in autonomic balance is linked to a higher risk of developing cardiovascular disease. Therefore, it is important to consider the restoration of this balance as a therapeutic goal. Heart rate variability is the most used method for evaluating ANS functions. In this review, studies investigating the effect of auricular VNS on HRV are evaluated. It has been observed that there is a need for research investigating the short- and long-term effects of stimulations performed with different parameters from different ears on cardiovascular parameters in healthy individuals and/or individuals with various clinical conditions. Thus, a more specific and effective use of auricular VNS for different clinical situations can be achieved.

Keywords

• Auricular vagus nerve stimulation
• heart rate variability
• autonomic dysfunction

Auriküler Vagus Sinir Uyarımının Kalp Hızı Değişkenliği Üzerindeki Etkisi

Abstract

Otonom sinir sistemi (OSS), istemsiz olarak çalışan ve hayati fonksiyonları kontrol eden bir yapıdır. Vagus Sinir Uyarımı (VSU), sempatik ve parasempatik sinir sistemi aktivasyonu arasındaki dengesizlik durumlarında OSS işlev bozukluklarını ele almaya odaklanan yeni bir tedavi yöntemidir. VSU ile parasempatik aktivite (PA) artarken sempatik aktivite (SA) azalır ve bu durum kardiyovasküler parametreleri etkiler. Kalp hızı her atışta dalgalanır ve dolayısıyla PA ve SA sinyallerinin sinoatriyal düğüm üzerindeki etkisini yansıtır. Araştırmalar, bireyler yaşlandıkça kalpteki PA tonunun azaldığını, SA tonunun ise arttığını göstermektedir. Vagal tonu değerlendirmek için kalp hızı değişkenliği (KHD) ve solunum sinüs aritmisi kullanıldığında, PA'nın kalp üzerindeki kontrolünde bir düşüş gösterirler. Otonom dengedeki bu değişim, kardiyovasküler hastalık geliştirme riskinin artmasıyla bağlantılıdır. Bu nedenle, bu dengenin yeniden sağlanmasını terapötik bir hedef olarak düşünmek önemlidir. Kalp hızı değişkenliği, OSS fonksiyonlarını değerlendirmek için en çok kullanılan yöntemdir. Bu derlemede, auriküler VSU'nun HRV üzerindeki etkisini araştıran çalışmalar değerlendirilmiştir. Sağlıklı bireylerde ve/veya çeşitli klinik rahatsızlıkları olan bireylerde, farklı kulaklardan farklı parametrelerle yapılan uyarımların kardiyovasküler parametreler üzerindeki kısa ve uzun vadeli etkilerini araştıran araştırmalara ihtiyaç olduğu gözlemlenmiştir. Böylece, farklı klinik durumlar için auriküler VSU'nun daha spesifik ve etkili bir şekilde kullanılması sağlanabilir.

Keywords

• Auriküler vagus sinir uyarımı
• kalp hızı değişkenliği
• otonomik disfonksiyon

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