Swallowing-induced supraventricular arrhythmia: A different perspective to mechanismS Ozturk1, E Yetkin2
1 Department of Cardiology, Ankara Education and Research Hospital, Ankara, Turkey
2 Department of Cardiology, Faculty of Medicine, Istinye University, Liv Hospital, Istanbul, Turkey
Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/jpgm.JPGM_21_20
Source of Support: None, Conflict of Interest: None
Keywords: Antiarrhythmic therapy, atrial fibrillation, cross-talk, supraventricular arrhythmia, swallowing-induced atrial fibrillation
Atrial fibrillation (AF) is a supraventricular arrhythmia (SVA), which is characterized by uncoordinated electrical activation of the atrium and an irregular, usually rapid, ventricular response causing hemodynamic instability. It is the most common SVA worldwide. AF is associated with increased risk of stroke, heart failure, and a major cause of morbidity and mortality. Its prevalence increases with aging and cost of treatment is expensive.
Swallowing-induced supraventricular arrhythmia (SI-SVA) is an uncommon clinical entity and defined as SVAs including premature atrial contraction (PAC), paroxysmal atrial tachycardia (PAT), and paroxysmal atrial fibrillation (PAF), which occur continuously during a wet or dry swallow. Since the first case report was published in 1926 about this topic, approximately 50 cases have been published since that time., Despite several proposed mechanisms such as direct mechanical stimulation of the left atrium, parasympathetic system activation, or presence of an adrenergic reflex originating from esophagus, the true mechanism of SI-SVA remains unknown. Herein, we describe a case of a patient presenting with SI-SVA, which started 2 weeks ago and successfully treated with antiarrhythmic treatment. In addition, we discuss possible mechanisms of SI-SVA and propose an alternate pathophysiological mechanism for SI-SVA.
A 67-year-old man presented with the complaints of recurrent episodes of sensation of palpitation and short duration pressure on his chest while swallowing lasting for 2 weeks. Palpitations occurred each time the patient swallowed solids but not liquids and lasted for a few seconds. He denied syncope, chest pain, fatigue, and shortness of breath. Detailed anamnesis of the patient revealed history of coronary artery by-pass graft (CABG), well-controlled hypertension, reflux esophagitis, and familial Mediterranean fever. He denied smoking, excessive amount caffeine, alcohol or any recreational drug consumption. Otherwise, he was free of risk factors such as diabetes mellitus, obesity, and obstructive sleep apnea syndrome. He was on nebivolol, acetylsalicylic acid, irbesartan, esomeprazole, and colchicum treatment due to his preexisting diseases. Physical examination revealed S1, S2 with a regular rhythm and no murmurs, S3 or S4. His blood pressure and heart rate were within the normal range. Twelve-lead resting electrocardiography (ECG), transthoracic echocardiography, and exercise test were within normal limits. Blood tests including hepatic, renal, and thyroid function tests, and complete blood count were also normal. Ambulatory rhythm Holter monitoring was planned and patient was informed to record his symptoms and eating time during the day. Holter monitoring revealed intermittently occurring short run supraventricular tachycardia attacks indicating PAF or atrial tachycardia consistent with the patient's repasts, swallowing and symptoms [Figure 1]. Attacks were noted only during eating. Then, real-time ECG was performed during solid food swallowing in the clinic and showed short duration of supraventricular runs suggestive of AF consistent with the patient's symptoms [Figure 2]a. Therefore, nebivolol treatment was ceased due to bradycardia and amiodarone 200 mg twice daily was prescribed to the patient. One week later, swallowing-induced palpitations improved and ECG obtained in the clinic during solid swallowing was free of an arrhythmia [Figure 2]b. At the end of 3-month clinical follow-up, the patient never experienced palpitation attacks during swallowing or at any time.
There is limited data regarding the mechanisms of SI-SVA in the literature. Herein, we have added a different perspective to the pathophysiological origin of SI-SVA in the light of this case report. SI-SVA is a rare clinical syndrome and its prevalence is nine times more in men than women. Most cases occur over 35 years of age and tachyarrhythmia occurs continuously shortly after each swallow. PACs and/or PAT are the most common observed arrhythmia in this clinical condition. Although there is not a standardized treatment modality, treatment with antiarrhythmic drugs or radiofrequency catheter ablation is preferred regimens. In our case report, our patient was a 67-year-old man and PAF occurred each time the patient swallowed solids. We chose to start medical therapy instead of an invasive procedure and tachycardia attacks stooped in a week.
What needs to be discussed in the light of this case report is the pathophysiological mechanism causing SI-SVA. There have been various suggestions from different studies regarding the mechanism. Mechanical stimulation of the left atrium by esophageal distension, vasovagal stimulation of the atrial myocardium, and adrenergic reflex originating from esophagus were the postulated mechanisms although their adaptability were only limited to a few cases., However, an association between gastroesophageal reflux disease and AF development was also discussed in a previous report. Similarly, our patient had reflux esophagitis and was stable with esomeprazole treatment. Besides, we had previously published an interesting case of a SVT patient presenting with gastroesophageal reflux symptoms, which encouraged us to suggest that the relationship between gastrointestinal system and SVAs and the pathophysiological mechanism is more complicated and interesting than thought. Considering the fact that our patient had a history of CABG surgery, it is also reasonable to suggest that handling of nerves during surgery, specifically cardiac thoracic ganglia, might have facilitated the development of AF in this patient; however, further explanation is needed to clarify its relevance with swallowing.
Another possible explanation regarding SI-SVA, which was not mentioned previously in the literature, is the cross-talk during the spreading of impulse through the nervous system. Interconnection of afferent innervations in the vagus nerve might be a reasonable explanation for SI-SVA. This interconnection might be at the tissue level or during the propagation of impulse through the vagus nerve or sympathetic ganglions. However, it is difficult to explain these interconnections solely by vagus nerve mediated mechanism. On the contrary of what we have seen in our case, vagus nerve dominated mechanism would have led a decrease in heart rate either during or preceding the arrhythmia period. Since we have not documented any bradycardia period during the SVA attack, it is likely there may exist mechanisms other than vagus nerve. Cross-talk between the cardiac afferent nerves and nerves responsible for swallowing through cervical ganglia and spinal cord might have resulted in SVA during swallowing. The swallowing reflex elicited by primary afferent nerves might have been modified by cardiac afferent nerves. It is well-known that cardiac plexus nerve synapses in thoracic and cervical ganglions in which cranial nerve fibers also cross the synapses., Atypical presentations of SVA are very common in the literature and in our study group, we have described some of them such as burping and cough attacks. In those case reports, we had also speculated the plausible mechanism to be the cross-talk of impulses during their spreading through the nervous system.
In conclusion, we have postulated cross-talk of nerves during the impulse propagation as a novel pathophysiological mechanism to SI-SVA in the literature for the first time. This hypothesis should be confirmed by further case reports and studies.
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[Figure 1], [Figure 2]