A case of swallowing-induced atrioventricular block after myocardial infarction

Swallow syncope associated with complete atrioventricular block in an adolescent

We describe a 16-year-old female with a history of swallowing-induced syncope. The physical examination, ECG, echocardiography, barium swallow test, and thyroid function tests were within normal limits. The ambulatory ECG revealed intermittent complete atrioventricular block only associated with swallowing. There was also intermittent first-degree atrioventricular block not related to eating. An electrophysiologic study was performed during the implantation of a single-chamber transvenous ventricular pacemaker. There was mild atrioventricular nodal conduction disturbance with a His-ventricular interval of 70 msec and Wenckebach cycle length of 420 msec. During 1 year follow-up, the patient remained asymptomatic.

Paroxysmal atrioventricular block: clinical experience with 20 patients

BACKGROUND

Paroxysmal atrioventricular (AV) block is an ill-defined entity, previously described in sporadic cases in association with vasovagal reaction, coronary angiography and distal conduction disease.

METHODS

We describe 20 patients (10 women) aged 26 to 80 years with symptomatic paroxysmal AV block.

RESULTS

Eight patients had ischemic heart disease-three with dilated cardiomyopathy, and two with co-existing carotid sinus hypersensitivity. Eight were taking chronic AV blockers. In five patients, the paroxysmal AV block occurred during a vagal reaction, in one during migranotic headaches, in one following aortic valve replacement and in one while recovering from acute myocardial infarction. The events lasted between 2.2 and 36 s. In 10 patients, the QRS configuration on the electrocardiogram was wide. Immediate treatment consisted of intravenous atropine and fluid supplements in two patients, discontinuation of the AV blocking agents in four, and the insertion of a temporary pacemaker in eight. Seventeen patients required a permanent pacemaker.

CONCLUSIONS

Paroxysmal AV block is an underestimated clinical entity related to vagal reaction, AV blocking drugs and distal conduction disease. Most of our patients eventually required implantation of a permanent pacemaker.

Paroxysmal atrioventricular block induced during head-up tilt testing in an apparently healthy man

INTRODUCTION

Prolonged asystole during head-up tilt testing has been reported, but the occurrence of paroxysmal AV block appears to be rare.

METHODS AND RESULTS

A 25-year-old man with no history of syncope underwent head-up tilt testing. After 11 minutes of 80 degrees tilting, he developed syncope with paroxysmal AV block and asystole lasting 10.5 seconds. However, this response was not reproduced during a subsequent tilt test 4 weeks later. Treadmill exercise testing and Holter monitoring showed no abnormalities. Power spectral analysis of heart rate variability revealed a marked increase in sympathetic activity several minutes before the induction of paroxysmal AV block.

CONCLUSION

We report a case of paroxysmal AV block that occurred during head-up tilt testing but did not recur on a subsequent test in an apparently healthy young man.