Short QT syndrome

To the Editor:

Long QT syndromes can be congenital or acquired. Acquired cases have been described in association with severe bradycardia, hypokalemia, and with the use of antiarrhythmic drugs of class IA, IC, and III; antihistaminic agents; cisapride; and pentamidine, among others. A proposed pathogenic mechanism for this syndrome is a disproportionate activity of the left cervical sympathetic ganglions. In fact, pharmacologic blockade of the left stellate ganglion[1] or left cervical sympathectomy[2] have been successfully used in patients not responding to [Beta]-blockers. Moreover, prolongation of the QT interval has been noted in various studies of patients with extensive surgical neck dissection[3] or thoracic surgery.[4] In these cases, no association with ventricular malignant arrhythmias has been described.

We report a case of a 79-year-old man admitted to our hospital in October 1998 because of a sudden loss of consciousness with sphincter relaxation, while cycling, and no other accompanying symptoms. The patient had been a heavy smoker (60 cigarettes per day) until 3 years before. He was taking no medication. He had felt healthy until 2 months before admission, when he noticed a painless nodule in the right area of the tongue base and a progressively enlarging mass in the right submandibular and cervical area, with dysphagia for solid food and weight loss (6 kg).

Physical examination was unremarkable except for the cervical mass affecting the tongue base as well as the right submandibular and cervical area (which was hard, uneven, and painless), and an arrhythmic pulse. The blood cell count, biochemical parameters, and urine test results were normal, An ECG recorded on admission showed sinus rhythm with ventricular premature complexes and a long QT interval (0.52 s). The QTc was 0.54 s (QTc = QT/[square root of R-R]). A 24-h ECG monitoring disclosed frequent ventricular and atrial premature complexes, short episodes of supraventricular and ventricular tachycardia, some of them with torsade de pointes appearance. A CT scan of the neck showed a nonuniform mass in the right cervical area, affecting the internal jugular lymph nodes and the internal jugular vein, reaching the parotid gland and the fight mandibular branch, together with swelling of right oropharynx and tongue base. A biopsy specimen of the mass was indicative of squamous carcinoma.

The patient was treated with magnesium, 2 g by the day (IV at first and orally thereafter), with normalization of the QT interval and disappearance of arrhythmias. Radiotherapy (cobalt) was given in the right cervical area, which produced clinical improvement and disappearance of the tumoral mass and the lymph nodes. Oral magnesium was discontinued once radiotherapy had concluded. Neither prolongation of the QT interval nor arrhythmias occurred, and the patient did not present any further syncope. Six months later, the tumor regrew in the tongue base and right tonsil, but the right cervical area was not affected, and the ECG was normal. The patient died due to bronchopneumonia in January 2000. In summary, our patient presented syncope with a long QT interval and torsade de pointes ventricular tachycardia, and a squamous carcinoma of the tongue, infiltrating adjacent neck structures and affecting the right lateral cervical sympathetic ganglions.

We are not aware of reported cases of sympathetic cervical ganglion infiltration by a tumor with long QT interval and ventricular arrhythmias. In our patient, the tumor affected the area surrounding the right jugular vein and probably some of the right sympathetic cervical ganglions. This could have caused a disbalanced sympathetic enervation of the heart, the exact opposite effect of left sympathectomy,[5] thereby originating prolongation of the QT interval. Treatment with IV magnesium during ventricular tachycardia episodes has proved effective,[6] although there are no reported references of chronic treatment with oral magnesium. Our patient was treated with oral magnesium until radiotherapy was finished, with disappearance of the tumoral mass affecting the right sympathetic cervical ganglions. The QT interval was normal thereafter, and there was no occurrence of arrhythmias and syncopes during this period.

Oscar Aramburu-Bodas, MD Antonio Cayon-Blanco, MD Juan Carlos Garcia-Rubira, MD Ramon Perez-Cano, MD Virgen Macarena University Hospital Seville, Spain

Correspondence to: Oscar Aramburu-Bodas, MD, C/Espinosa y Carcel, n [degrees] 57, 10 [degrees]-A, 41005-Sevilla, Spain; e-mail: oaramburub@ nexo.es

REFERENCES

[1] Hoepp HW, Eggeling T, Hombach V. Pharmacologic blockade of the left stellate ganglion using a drug-reservoir-pump system. Chest 1990; 97:250-251

[2] Coyer BH, Pryor R, Kirsch WM, et al. Left stellectomy in the long QT syndrome. Chest 1978; 74:584-586

[3] Acquadro MA, Nghiem TX, Beach TP, et al. Acquired QT interval changes and neck dissections. J Clin Anesth 1995; 7:54-57

[4] Dorian P, Newman D, Hughes W, et al. Torsade de pointes ventricular tachycardia following right pneumonectomy: insights into the relation between right cardiac sympathetic nerve damage, QT intervals, and arrhythmias. Int J Cardiol 1994; 46:292-296

[5] Schwartz PJ, Locati EH, Moss AJ, et al. Left cardiac sympathetic denervation in the therapy of congenital long QT syndrome: a worldwide report. Circulation 1991; 84:503-511

[6] Perticone F, Adinolfi L, Bonaduce D. Efficacy of magnesium sulfate in the treatment of torsade de pointes. Am Heart J 1986; 112:847-849

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