doi: 10.2169/internalmedicine.9305-21
Intern Med Advance Publication
http://internmed.jp【 CASE REPORT 】

Swallowing-induced Paroxysmal Atrial Tachycardia
Causes Weight Loss and Fainting During Mealtime:
A Case Report and Literature Review
Tsugumi Hosoe, Kenzo Uzu, Kiyohiro Hyogo, Ryosuke Takahashi, Sho Tamai,Tomoyuki Nagano, Yasushi Shimokawa, Soichiro Ota, Hideaki Okubo and Hiroki Shimizu

Abstract:
Swallow or deglutition syncope is an unusual disorder. We herein report an 80-year-old man with paroxysmal atrial tachycardia induced by swallowing, causing syncope. Initially, we suspected a digestive disorderand found no significant findings. Finally, a swallowing test with monitoring of the heart rate and blood pressure helped in the diagnosis. The patient was treated with antiarrhythmic drugs and catheter ablation. The
mechanism underlying swallowing-induced tachycardia presumably involves mechanical stimulation of theesophagus and autonomic nervous system effects. However, few cases have been reported, and the exact
mechanism remains unclear.
Key words: swallowing-induced tachycardia, paroxysmal atrial tachycardia, syncope, weight loss
(Intern Med Advance Publication)(DOI: 10.2169/internalmedicine.9305-21)

dysphagia during meals seven days prior to his visit, accompanied by fainting. He visited his previous doctor because ofanorexia and weight loss of 5 kg in a single week. As he
had a history of transverse colon cancer surgery six years
earlier, a detailed examination of his digestive tract was necessary, and he was referred to our hospital.
On an initial assessment, his vital signs were stable, andno abnormalities were noted in his physical examination, except for yellowing of the conjunctiva of the eyes due tophysiological jaundice, which had been noted previously.
Laboratory results of blood tests showed elevated bilirubinlevels, a decreased renal function, dyslipidemia, and elevatedbrain natriuretic peptide levels (Table). Chest radiography
was normal, and computed tomography (CT) of the chest
and abdomen showed no findings suggestive of malignant
disease.
Since the patient had a history of vasospastic angina, heunderwent myocardial deviated enzyme measurement, anelectrocardiogram (ECG), and transthoracic echocardiography, but no significant abnormal findings were found. The
ECG showed sinus rhythms with negative T waves in the III
and aVf leads (Fig. 1). After admission to the hospital, theIntroduction
Swallowing-induced atrial tachyarrhythmias are rare andare defined as a reproducible occurrence of supraventriculartachyarrhythmias, such as premature atrial contractions, paroxysmal atrial tachycardia, and paroxysmal atrial fibrillation,
during swallowing. They occur in approximately 0.6% ofpatients with paroxysmal atrial arrhythmias (1).
We herein report a rare case of a patient presenting withan eating disorder, lightheadedness, and weight loss who
was diagnosed by a swallowing test with swallowinginduced paroxysmal atrial tachycardia and later experienced
syncope. All symptoms could be traced to swallowinginduced atrial tachyarrhythmia. He was able to eat, and hisweight loss was ameliorated following treatment with antiarrhythmic drugs and radiofrequency catheter ablation therapy.

Case Report
An 80-year-old man presented to the hospital with a chiefcomplaint of fainting during meal times. He began to have

Department of Cardiology, Konan Medical Center, Japan
Received: December 28, 2021; Accepted: April 1, 2022; Advance Publication by J-STAGE: May 14, 2022
Correspondence to Dr. Kenzo Uzu, kenzouzu@gmail.com

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patient underwent a videoendoscopic evaluation of swallowing, upper gastrointestinal endoscopy, and contrast-enhanced
thoraco-abdominal CT to examine the gastrointestinal tract
further; however, no significant abnormalities were observedin the pharynx or esophagus. Thus, we found there to be nostructural or functional abnormality of the gastrointestinal
tract that could cause weight loss and anorexia.
We decided to scrutinize the syncope further, so we tooka detailed history of the fainting spells. Symptoms appeared
within 1 min of swallowing and lasted 2-3 s, and fainting
occurred even when swallowing saliva. After awakening,

Table.

there was no confusion in consciousness. Since there werescattered supraventricular arrhythmias on monitoring duringhospitalization, we decided to record the pulse with a 24-h
Holter ECG to understand the relationship between the patient’s lightheadedness and tachycardia in more detail. Frequent paroxysmal atrial tachycardia (PAT) occurred during
mealtime, and the occurrence of PAT coincided with lightheadedness during meals (Fig. 2). Therefore, a swallowing
test was performed to investigate vital signs and ECGchanges during swallowing. After ingesting carbonatedwater, PAT appeared within 1 min of swallowing, the pulse
rate increased from 94 bpm to 180 bpm, and the blood pressure decreased from 123/80 mmHg to 80/68 mmHg (Video).
The patient complained of pre-syncope symptoms, such as
lightheadedness and a floating sensation during the bloodpressure drop. The same tachycardia and pre-syncope symptoms were observed when cold water or solid food was ingested. Therefore, we hypothesized that swallowing would
induce PAT, which would decrease blood pressure and cause
syncope in this elderly and sensitive patient.
After 50 mg of intravenous pilsicainide, the patient wasable to ingest cold water and jelly without experiencing
PAT. From the next day, 75 mg of pilsicainide was administered orally daily. Because of the efficacy of oral pilsicainide and the polymorphic P wave during PAT on the surface ECG, drug therapy was chosen over catheter ablation.
However, regardless of swallowing, spontaneous regulartachycardia with a narrow QRS occurred frequently, and a
12-lead ECG showed a pseudo-s pattern in the lower limb
leads and an rSr’ pattern in the V1 lead, indicating that themechanism of this tachycardia was atrioventricular nodal reentry tachycardia (AVNRT) (Fig. 3). In contrast to PAT,AVNRT appeared at rest, regardless of swallowing, andcaused severe symptoms of palpitations and pre-syncope. Inaddition, catheter ablation of the right atrium only was considered curative. Therefore, an electrophysiological study
and radiofrequency catheter ablation were conducted the day

Laboratory Data on Admission.

Total protein (g/dL)
Albumin (g/dL)
TB (mg/mL)
DB (mg/mL)
AST (U/L)
ALT (U/L)
ALP (U/L)γ GT(U/L)LDH (U/L)CK (U/L)
CK-MB(ng/mL)
BUN (mg/dL)
Creatinine (mg/dL)
eGFR(mL/min/1.73m2)
Sodium(mEq/L)
Potassium(mEq/L)

7.5
4.52.2
0.6332560
172246279.5
49.8
1.33
40.4
146
3.3

Chloride (mEq/L)
Calcium (mEq/L)
LDL-C (mg/dL)
HDL-C (mg/dL)
TG (mg/dL)
CRP (mg/dL)
Glucose(mg/dL)
BNP (pg/mL)
NT-proBNP (pg/mL)
WBC (/uL)
RBC (/uL)
Hb (g/dL)
Platelet (/uL)
Trop I(ng/mL)
TSH (uIU/mL)
fT4 (ng/dL)

108
9.6
152
74
86
0.33
150
222.1
1110
6,290
4.5×106
14.6
174×103
0.012
1.036
1.3

TB: total bilirubin, DB: direct bilirubin, AST: aspartate transaminase, ALT:alanine transaminase, ALP: alkaline phosphatase, γ GT : γ -glutamyl trans peptidase, LDH: lactate dehydrogenase, CK: creatine kinase, BUN: blood ureanitrogen, eGFR: estimated glomerular filtration LDL-C: low density lipoprotein cholesterol, HDL-C: high density lipoprotein cholesterol, TG: triglyceride, CRP: C-reactive protein, BNP: brain natriuretic peptide, WBC: white
Blood Cell, RBC: red blood cell, Hb: hemoglobin, Trop I: troponin I, TSH:
thyroid-stimulating Hormone, fT4: free total thyroxine

Figure 1. Electrocardiogram data on admission showing sinus rhythms with negative T wave in theIII and aVf leads.
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Figure 2. A: A 24-h Holter electrocardiogram (ECG) showing tachycardia during mealtime. The
gray area on the ECG indicates tachycardia. B: Magnification of the circled area showing tachycardia
due to paroxysmal atrial tachycardia.

after the initiation of oral pilsicainide. Atrial extrastimulation methods were able to repeatedly induce thesame tachycardia with a narrow QRS and short RP that appeared clinically. Based on electrophysiological findings, adefinite diagnosis of slow-fast type AVNRT was made.
Therefore, radiofrequency catheter ablation was performed
to modify the slow pathway below the Koch’s triangle, andAVNRT was no longer induced.
We subsequently discontinued pilsicainide administration
on a trial basis, and PAT due to swallowing did not reappear. On the 6th postoperative day, we performed a 24-h
Holter ECG to monitor the patient without prescribing antiarrhythmic drugs. It revealed 93 single atrial premature
contractions, 6 double contractions, and 1 triple or morecontraction, which was a marked improvement over his earlier condition. No relationship was observed between swallowing and premature atrial contractions. The patient wasable to eat without any further symptoms and gained 3 kg in
7 days. The patient was discharged on the 10th postoperative day, which was the 22nd day of hospitalization.

Discussion
There are two types of arrhythmias induced by swallowing: bradycardia and tachycardia. While most cases arebradycardia, very rarely, swallowing can also induce tachycardia. Most cases of swallowing-induced bradycardia arecomplicated by diseases of the heart or esophagus; in contrast, most patients with swallowing-induced tachycardia
have a normal gastrointestinal tract and heart (1, 2).
Swallowing-induced atrial tachycardia was first described by
Sakai and Mori in 1926 as Schlucktachycardie, and to date,
only about 50 cases have been reported in the literature (1).
Although the underlying mechanism is unclear, several pre3

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DOI: 10.2169/internalmedicine.9305-21

Figure 3. The patient shows frequent narrow QRS tachycardia after oral pilsicainide, regardless ofswallowing. A retrograde P wave was observed, and the electrocardiogram was suggestive of atrioventricular nodal re-entrant tachycardia.

dictive mechanisms have been suggested in previous reports.
One theory suggests mechanical stimulation of the left
atrium by the distended esophagus as the cause, as Cohen etal. reproduced atrial fibrillation by inflating a balloon in theesophagus at the level of the left atrium (1, 2). However,this theory does not apply to all patients, as the reproducibility of this method of inducing tachycardia is not consistent, regardless of the position of the balloon in the esophagus, and dry swallowing can also induce tachyarrhythmias (1). The other putative mechanism involves the influence of the autonomic nervous system. Parasympathetic
nerve stimulation generally causes bradycardia, but vagal
nerve stimulation can shorten the relative refractory periodof the atria and can induce an abnormal rhythm, resulting intachycardia (3). In addition, it has been reported that heterogeneous depolarization of atrial muscle caused by sympathetic nerve stimulation is involved in the formation of focal
re-entry (1, 2).
A diagnosis of swallowing-induced tachycardia is madeby consistently recording data at the onset of symptoms andruling out other tachyarrhythmia mechanisms. Past reports
have recommended the use of a 24-h Holter ECG. In addition, upper gastrointestinal endoscopy may also be performed to confirm the presence of esophageal disease. Since
swallowing-induced atrial tachycardia is common in patientswith normal cardiac structures, an echocardiogram is also
recommended to confirm a lack of structural heart abnormalities (1). It is not uncommon for swallow-induced tachycardia to develop suddenly in adulthood, as in the present
case (4, 5). Although the mechanism is currently unknown,
it is thought to include a decrease in esophageal peristalsis
with age, exacerbation of autonomic dysreflexia, and progressive structural and electrical remodeling of the atrial
musculature. Based on the present findings, we believe thatthe swallowing stress test, which examines vital signs and
ECG changes during swallowing, effectively detects

swallowing-induced tachycardia and may be useful when encountering patients with similar symptoms.
When treating swallowing-induced tachycardia, the firststep is to avoid ingesting stimulants, such as coffee and colddrinks. As for pharmacotherapy, in some cases, like the present case, class I antiarrhythmic drugs are used. In othercases, atropine, catecholamines, and beta-blockers, which act
directly on the autonomic nervous system, have been used
for swallowing-induced tachycardia (6, 7). Since the effectiveness of certain drugs varies from case to case, the preferred choice has not yet been determined. In addition, surgical treatment has also been used to manage swallowinginduced tachycardia, including physical separation of the left
atrium from the esophagus by repositioning the esophagus,
and circular myotomy of the esophagus, as performed by
Kalloor et al. in the past (2, 8). However, in recent years,
surgical approaches have not been considered appropriate (1). Radiofrequency catheter ablation should be considered for ectopic foci in patients with a certainty of inducibility and only one or a few arrhythmia foci, as it can provide
a complete cure (4). In the present case, the modification of
the AVN slow pathway by radiofrequency catheter ablation
completely relieved the symptoms of AVNRT. Furthermore,
despite the absence of ablation therapy for PAT, PAT did notrecur after discontinuation of pilsicainide; it is possible thatthe source of PAT was in the vicinity of the ablation site for
AVNRT, but this does not fully explain why PAT with multiform P waves was cured. Since swallowing-induced tachycardia is considered to be affected by the autonomic nervoussystem, energization to the site in question might have affected the endogenous autonomic nervous system of theheart.
The present patient came to our hospital with a chiefcomplaint of rapid weight loss, anorexia, and syncope. Although gastrointestinal diseases, such as malignant tumors,
were first suspected, the symptoms were ultimately ex4

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Surg 21: 587-590, 2002.
4. Tada H, Kaseno K, Kubota S, et al. Swallowing-induced atrial
tachyarrhythmias: prevalence, characteristics, and the results of theradiofrequency catheter ablation. Pacing Clin Electrophysiol 30:
1224-1232, 2007.
5. Suarez LD, Chiozza MA, Foye R, Mosso H, Perosio AM.
Swallowing-dependent atrial tachyarrhythmias. Their mechanism.
Journal Electrocardiol 13: 301-305, 1980.
6. Tandeter H, Kobal S, Katz A. Swallowing-induced atrial tachyarrhythmia triggered by salbutamol: case report and review of theliterature. Clin Cardiol 33: E116-E120, 2010.
7. Wilmshurst PT. Tachyarrhythmias triggered by swallowing andbelching. Heart 81: 313-315, 1999.
8. Kalloor GJ, Singh SP, Collis JL. Cardiac arrhythmias on swallowing. Am Heart J 93: 235-238, 1977.

plained in a unified manner by tachycardia caused by swallowing. A swallowing stress test with an ECG and vital signmonitoring was useful in the diagnosis of swallowinginduced tachycardia. Swallowing-induced tachycardia is indeed a very rare condition but should be kept in mind as apotential cause of syncope.
The authors state that they have no Conflict of Interest (COI).

References
1. Mathew R, Green MS, Nery PB. Swallowing-induced atrial tachycardia. CMAJ 190: E507-E509, 2018.
2. Burton JR, Sachs HJ, Keon WJ, FitzGibbon GM. Intrapleural positioning of esophagus for treatment of swallowing-induced arrhythmia. Chest 79: 367-368, 1981.
3. Gordon J, Saleem SM, Ngaage DL, Thorpe JA. Swallow syncope
associated with paroxysmal atrial fibrillation. Eur J Cardiothorac

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