BACKGROUND: Sinus node dysfunction (SND) is caused not only by intrinsic sinus node disease, but also by the extrinsic factors. Among the extrinsic factors, autonomic imbalance is most common. Symptomatic SND usually requires permanent pacemaker therapy. However, the clinical characteristics and patient response to medical therapy for hypervagotonic SND have not been properly clarified. MATERIALS AND METHODS: Thirty two patients (14 men, 18 women, 51 +/- 14 years) with hypervagotonic SND were included in this study, but those patients who had taken calcium antagonists, beta-blockers or other antiarrhythmic drugs were excluded. Hypervagotonic SND was diagnosed if the abnormal electrophysiologic properties of the sinus node were normalized after the administration of atropine (0.04 mg/kg). RESULTS: The presenting arrhythmias were 16 cases of sinus bradycardia (50.0%), 12 of sinus pause (37.5%), 3 of sinoatrial block (9.4%) and 1 of tachy-bradycardia (3.1%). Nine (28.1%) patients had hypertension, 7 (21.9%) smoked, 2 (6.3%) had diabetes mellitus, and 1 (3.1%) had hypercholesterolemia. Among the patients, 3 had no remarkable symptoms, 13 had dizziness, 7 had syncope, 3 had weakness and 6 had shortness of breath. Twenty five (78.1%) patients were treated with theophylline, 1 patient with tachy-bradycardia syndrome was treated with digoxin and propafenone, and 6 (18.8%) were treated with no medication. During the 43 +/- 28 month follow-up, 25 patients remained asymptomatic, but 6 who took no medication developed mild dizziness. One patient needed permanent pacemaker implantation owing to recurrent syncope despite of theophylline treatment. CONCLUSION: These results show that hypervagotonic SND has a benign course and most of the patients can be managed safely without implanting a pacemaker. (Ed note: I like the abstract. It is short and direct, as it should be.)
Dizziness/etiology ; Dyspnea/etiology ; Female ; Humans ; Male ; Middle Aged ; Muscle Weakness/etiology ; Sick Sinus Syndrome/*complications/drug therapy ; Syncope/etiology ; Theophylline/therapeutic use ; Vasodilator Agents/therapeutic use

Recurrent syncope as a complication of recurrent neck malignancy is an uncommon but well documented association. The syncope is presumed to occur when a tumor mass invades the baroreceptor within the carotid sinus or when it disrupts the afferent nerve fibers of the glossopharyngeal nerve. A 59-year-old man presented with recurrent syncope and headache. He had a wide local excision including tonsillectomy and modified left radical neck dissection for tonsilar cancer 4 years ago. A computed tomography scan revealed ill-defined lesions in left parapharyngeal, carotid space and right upper jugular region. After clinical evaluation, cardiac pacemaker was placed, but he still suffered from the syncope. Then, he received the chemotherapy with docetaxel and cisplatin. The last hypotension event occurred on day 10 of the chemotherapy. Six months after 3 cycles of chemotherapy, he remained in complete remission and resolution of syncope. We report a case in which syncope was associated with a recurrence of tonsilar cancer and successfully treated with chemotherapy.
Antineoplastic Combined Chemotherapy Protocols/*therapeutic use ; Carcinoma, Squamous Cell/*complications/drug therapy/radiography ; Cisplatin/*therapeutic use ; Head and Neck Neoplasms/*complications/drug therapy/radiography ; Humans ; Male ; Middle Aged ; Neoplasm Recurrence, Local/*complications/drug therapy ; *Pacemaker, Artificial ; Syncope/*drug therapy/etiology ; Taxoids/*therapeutic use ; Tonsillar Neoplasms/*complications/drug therapy/radiography