Intermittent complete heart block associated with swallowing as a complication of acute myocardial infarction

Deglutition Syncope Due to Exaggerated Vagal Reflex

Swallow or deglutition syncope is an uncommon cause of syncope associated with bradyarrhythmia and hypotension during food swallowing. Early recognition of this condition is imperative but challenging. We report a case of a 60-year-old female who presented with a complaint of intermittent lightheadedness after swallowing food. An episode of presyncope was observed and a reduced pulse rate from baseline was noted when she was instructed to eat a candy bar in the clinic. Further workup revealed normal in-office electrocardiogram, bilateral carotid ultrasound, transthoracic echocardiogram, and videofluoroscopic swallow study. Our goal in presenting this case is to raise awareness of the condition in medical literature and provide a good understanding of its clinical manifestation to prevent life-threatening events.

Swallow syncope: a case report and review of literature

Background

Swallow or deglutition syncope is an unusual type of neurally-mediated syncope associated with life-threatening bradyarrhythmia and hypotension. It is a difficult condition to diagnose with commonly delayed diagnosis and management. There is lack of review articles that elucidate the basic demographics, clinical characteristics and management of this rare condition. This publication systematically reviews the 101 case reports published since 1793 on swallow syncope.

Case presentation

A 59-year-old man presented with the complaint of recurrent dizziness associated with meals. A 24-h ambulatory ECG recording confirmed an episode of p-wave asystole at the time of food intake. Oesophagogastroduodenoscopy with balloon inflation in the mid to lower oesophagus resulted in a 5.6 s sinus pause. The patient’s symptoms resolved completely following insertion of a permanent dual chamber pacemaker.

Conclusions

Swallow syncope is extremely rare, but still needs to be considered during diagnostic workup. It is commonly associated with gastro-intestinal disease. Permanent pacemaker implantation is the first line treatment.

Deglutition Syncope: Two Case Reports Attributed to Vagal Hyperactivity

Deglutition syncope is a relatively rare cause of syncope that belongs to the category of neurally mediated reflex syncopal syndromes. The phenomenon is related to vagal reflex in context to deglutition causing atrioventricular block and acute reduction in cardiac output leading to dizziness or syncope. We present case series of two cases of deglutition syncope, of which first was managed medically and second with pacemaker implantation.

An uncommon case of right-sided throat pain and swallow syncope

A 63-year-old man presented with recurrent syncopal attacks associated with swallowing and right-sided throat pain. Immediately after admission, he presented a 16-s asystolia. The patient's clinical history was unremarkable except for previous postimplant periodontitis. Several episodes of severe bradycardia and sinus pauses, always associated with painful deglutition, were recorded subsequently. X-ray orthopanthomography and magnetic resonance imaging of the neck confirmed several areas of periodontitis around the previous dental implants and right mastoid inflammation. A barium swallow and fibre-optic endoscopy also revealed a small sliding hiatus hernia and distal chronic oesophageal inflammation. Despite complete dental curettage, antibiotics and antigastro-oesophageal reflux therapy, only partial relief of the pain and incomplete resolution of the arrhythmic disorder were obtained after 3 weeks, and the patient underwent pacemaker implantation. At 1-month follow-up, however, he reported the complete relief of the throat pain; subsequent Holter monitoring showed normal sinus rhythm, without pacemaker-induced electrical activity.

Swallow Syncope, a Case Report and Review of the Literature

Swallow syncope is a relatively rare syndrome that is treatable when diagnosed. A 66-year-old woman was referred to the department of cardiology because she had been suffering from recurrent syncopal attacks associated with swallowing. An ambulatory electrocardiogram revealed atrial and ventricular asystoles immediately after swallowing soup or tea that were reproducible (max. RR 3.5 s). An electrophysiological study did not detect sinus nodal or atrioventricular nodal dysfunction. The patient had no underlying esophageal disease or cardiac disorder. The patient's symptoms resolved after permanent pacemaker implantation. This report reviews the diagnosis, mechanism and management of swallow syncope.

A case of swallowing-induced atrioventricular block after myocardial infarction

We report a patient with transient atrioventricular (AV) block induced by swallowing. He complained of recurrent dizziness during meals and had suffered from inferior myocardial infarction 1 year before the onset of these symptoms. Radiologic examination showed no apparent esophageal abnormalities. Swallowing a piece of solid food or hot liquid repeatedly provoked advanced AV block. Administration of intravenous atropine sulfate prevented AV block. An electrophysiologic study revealed that this swallowing-induced AV block was an intranodal (A-H) block. We did not implant a cardiac pacemaker because his symptoms were not very serious and could be prevented by eating carefully. The patient has been symptom-free for the past 12 months. The previous myocardial infarction may be related to the appearance of this vagal-related AV block.

Diagnostic evaluation of syncope

Syncope is a common medical problem and is caused by a wide variety of diseases ranging from physiologic derangements with few consequences to conditions that may be immediately life-threatening. Because of the large differential diagnosis, many diagnostic tests are available for its evaluation. However, a cause of syncope is not established in 38% to 47% of patients despite these tests. In those patients in whom a diagnosis can be assigned, the history and physical examination identify a potential cause in 49% to 85%. Furthermore, in 8% of additional patients, history and physical examination are suggestive of causes that need confirmation by specific tests. Routine blood tests rarely yield diagnostically helpful information. In those patients in whom a potential cause for syncope is identified, arrhythmias are diagnosed by electrocardiogram in 2% to 11% of patients, cardiac monitoring in 3% to 27% (telemetry or Holter), stress test in less than 1%, carotid massage in less than 1%, and electrophysiologic studies in less than 3%. Diagnosis of arrhythmias as a cause of syncope is problematic because symptomatic correlation during electrocardiographic monitoring is rarely found (approximately 4%), and as a result, there is no uniform agreement on diagnostic criteria for abnormalities. Similar problems exist in the use of electrophysiologic studies. Upright tilt testing and psychiatric examination may be useful in evaluation of recurrent syncope of unknown cause in patients without organic heart disease. Based on the results of recent studies, strategies for evaluation of patients with syncope are possible that utilize selective and goal-directed diagnostic testing.

Swallow syncope after aneurysmectomy of the thoracic aorta

A case of swallow syncope is presented and 30 previously reported cases from the literature in English are reviewed. A 67-year-old male developed syncope on swallowing 3 months after the resection of an aneurysm of the descending thoracic aorta. Electrocardiographic monitoring during eating demonstrated sinus bradycardia and sinus arrest with loss of consciousness. Neither Valsalva's maneuver nor carotid massage could produce bradycardia or syncope. Intravenous administration of edrophonium produced sinus bradycardia and the drinking of water by the patient after edrophonium administration brought about sinus bradycardia and sinus arrest with loss of consciousness. Sinoatrial node and atrioventricular node functions, evaluated by an atropine test, overdrive suppression test, and His bundle electrocardiogram were normal. No pathological changes were observed following a barium swallow. The patient was treated with a permanent pacemaker.

Swallowing syncope: observations in the absence of conduction system or esophageal disease

A patient is described with the clinical syndrome of "swallowing syncope" who reproducibly demonstrated sinus bradycardia, A-H prolongation, and intranodal atrioventricular block in response to swallowing during electrophysiologic study. Baseline electrophysiologic and esophageal manometric results were normal, as was his response to other vagal maneuvers. Demand ventricular pacing alleviated his symptoms. These findings suggest that "swallowing syncope" is mediated via an esophageocardiac reflex and can occur in the absence of cardiac conduction system or esophageal disease.

Paroxysmal supraventricular tachycardia initiated by a swallowing-induced premature atrial beat

We report a unique patient in whom electrophysiologic studies elucidated the mechanism of a rare form of swallowing-induced atrioventricular reentrant tachycardia, and for whom successful surgical ablation of an accessory pathway abolished intractable episodes of palpitation. A 64-year-old man was incapacitated by frequent attacks of palpitation following swallowing. Electrocardiograms documented paroxysmal supraventricular tachycardias initiated by a premature atrial beat or beats following swallowing. During electrophysiologic studies swallowing consistently induced premature atrial beats which in turn initiated a sustained atrioventricular reentrant tachycardia incorporating a retrogradely conducting left-sided concealed accessory pathway. The atrial activation sequence related to the premature atrial beats and the morphology of the premature P waves suggested that premature atrial beats originated in the right atrium. The mechanism of induction of premature atrial beats following swallowing remains obscure in our patient. Antiarrythmic drugs failed to prevent induction of sustained tachycardias during sequential electrophysiologic studies. The patient underwent successful surgical ablation of the accessory pathway and is free from palpitation 15 months after the surgery.

A morphologic study on human conduction system of heart considering influences of some disorders of individuals

The authors have investigated the aging changes of the human AV node, AV bundle, and bundle branches considering the influences of various disorders of individuals upon these conduction tissues. These conduction tissues began to develop gradually from the infant stage and the development was completed by young adult stage. Aging changes of the conduction tissues were fat infiltration, fibrosis and elastosis, disappearance of muscle fiber, and general atrophy of the conduction tissues. They were thought to occur not only by aging but also by the influences of various disorders particularly of long-standing chronic diseases. Changes of the conduction tissues seem to be related with thickening and luminal narrowing of the AV nodal artery and superior ventricular septal arteries. Marked elastosis or atrophy was noted in the cases suffering from some long-standing disorder regardless of the sort of disorders. In the cases which were diagnosed as complete heart block clinically, destruction of the conduction tissues was extremely severe including those of the SA node.

Swallowing-dependent atrial tachyarrhythmias. Their mechanism

We describe here the case of one patient who exhibited several types of atrial tachyarrhythmias induced by swallowing. There was no evidence of other cardiac or gastroesophagic abnormalities. The electrophysiologic study demonstrated a second degree A-V block due to block within the atria. Our findings suggest that the mechanism operative may be an intra-atrial micro-reentry induced by an increased vagovagal reflex triggered by the normal esophageal peristalsis.

Clinical and electrophysiologic findings in patients with paroxysmal slowing of the sinus rate and apparent Mobitz type II atrioventricular block

Over five years, 13 patients with episodic apparent type II atrioventricular (AV) block associated with sinus slowing were seen. This phenomenon occurred only transiently during an acute illness in eight patients (group I) but recurred chronically in five (groupII). For the group as a whole, the mean spontaneous cycle length was 42% longer during the period of AV block compared with periods of 1:1 AV conduction (800 +/- 116 msec to 1138 +/- 489 msec) (P less than 0.05). Electrophysiologic studies in four group I patients showed no abnormalities, whereas abnormalities in AV nodal conduction and refractoriness or provocation of intranodal Mobitz type II AV block (during carotid massage) were observed in three patients in group II and were totally abolished by atropine. In group I patients, apparent type II AV block was self-limited. In the chronic group, recurrent symptoms required insertion of permanent pacemakers in two patients. Simultaneous type II block and sinus slowing appeared to be related to the effects of increased vagal tone on both nodal structures. Intracardiac pacing is not indicated for patients with transient episodes associated with an acute illness, but may be required for symptomatic patients with recurrent episodes.

Mobitz type II block without bundle-branch block

His bundle (H) electrograms were recorded in three patients with Mobitz type II block and narrow QRS. Block was secondary to digitalis intoxication in one patient. In the second patient, who had first-degree A-V block, type II block occurred with atrial pacing at a slightly increased heart rate. In the third patient, who had corrected transposition of the great vessels, type II block occurred spontaneously. In two additional patients, block simulating type II block was noted. In one, block of single P waves occurred with carotid massage. In the other, Wenckebach periods with small increments in P-R (and P-H) intervals resembled episodes of type II block. In all five patients, block was proximal to H, suggesting the A-V node as the site of block. The conduction defects in these patients were not progressive; none of the patients needed a pacemaker.

Although these mechanisms were identified in patients with narrow QRS complexes, they could occur with bundle-branch block suggesting an erroneous diagnosis of bilateral bundle-branch disease. It is concluded that His bundle recording is helpful in delineating these benign forms of block. The site of block may be a more important determinant of prognosis than the type of block.