Q-T Interval Syndrome

Lipp, Pitt, Anderson and Zimmet, The Medical Journal of Australia (1970),2223 describe a twenty-year-old male with recurrent syncopal episodes as well as two documented episodes of ventricular fibrillation associated with prolongation of Q-T interval. After the patient was stabilized following a severe episode of fibrillation, he was placed on oral PHT and had no further arrhythmias. He remained free of syncope during the eighteen-month follow-up period. The authors conclude that PHT is probably the most effective drug for the management of this syndrome since it suppresses myocardial irritability as well as reducing paroxysmal autonomic discharge.

2223. Lipp, H., Pitt, A., Anderson, S.T. and Zimmett, R., Recurrent ventricular tachyarrhythmias in a patient with a prolonged Q-T interval, Med. J. Aust., 1296-9, 1970.

Cochran, Linnebur, Wright and Matsumoto, Clinical Research (1977),1776 did electrophysiologic studies of three patients with hereditary long Q-T interval syndrome. When admitted to the hospital these patients had ventricular tachyarrhythmias unresponsive to maximum doses of intravenous lidocaine. At this point DC counter-shock was used to terminate ventricular tachycardia in two patients. In the third patient, intravenous PHT promptly terminated the tachyarrhythmia. Intravenous PHT shortened the QT interval in all three patients.

1776. Cochran, P. T., Linnebur, A. C., Wright, W. and Matsumoto, S., Electrophysiologic studies in patients with long Q-T syndrome, Clin. Res., 25(2): 88A, Feb. 1977.

Schneider, Bahler, Pincus, Stimmel, Chest (1977),2069 describe a forty-five-year-old patient with congenital prolongation of the Q-T interval and recurrent ventricular arrhythmias. After numerous efforts to stabilize the patient, a transvenous pacemaker was inserted to suppress ectopic activity. Attempts to decrease the pacemaker rate below 150 per minute resulted in recurrence of ventricular arrhythmias and the Q-T interval remained prolonged. The patient was placed on oral PHT (200 mg t.i.d.), the Q-T interval decreased and her ECG returned to normal. She had no further episodes of premature ventricular systoles or syncope, and was subsequently discharged on 200 mg PHT twice daily.

2069. Schneider, R. R., Bahler, A., Pincus, J. and Stimmel, B., Asymptomatic idiopathic syndrome of prolonged Q-T interval in a 45-year-old woman, Chest, 71: 210-3, 1977.

Brown, Liberthson, Ali and Lowenstein, Anesthesiology (1981),2361 report a post-operative patient with prolonged Q-T interval and episodes of ventricular ectopic beats progressing to ventricular tachycardia. Oral PHT was started after numerous medications had been unsuccessful over a thirty-hour period. With PHT, no further ectopic beats were observed, even after discontinuation of lidocaine. Maintained on PHT and examined four weeks later, she had normal sinus rhythm and no ectopic activity. See also Refs. 1972, 2071, 2094, 2223, 2328, 2370, 2376, 2462, 2558, 2695, 2807, 2837, 2895, 2951, 2957, 3066.

2361. Brown, M., Liberthson, R. R., Ali, H. H., Lowenstein, E., Perioperative anesthetic management of a patient with long Q-T syndrome (LQTS), Anesthesiology, 55: 586-9, 1981.
1972. Mathews, E. C., Blount, A. W. and Townsend, Q-T prolongation and ventricular arrhythmias, with and without deafness, in the same family, Am. J. Cardiol., 29:702-11, 1972.
2071. Schwartz, P. J., Periti, M. and Malliani, A., The long Q-T syndrome, Am. Heart J., 89(3): 378-90, 1975.
2094. Suratt, P. M., Crampton, R. S. and Carpenter, M. A., Benign familial biventricular dysrhythmias with syncope limited to late childhood, adolescence and early youth, Circulation, 48 (Suppl. IV): 222, 1973.
2223. Lipp, H., Pitt, A., Anderson, S.T. and Zimmett, R., Recurrent ventricular tachyarrhythmias in a patient with a prolonged Q-T interval, Med. J. Aust., 1296-9, 1970.
2328. Bhandari, A. K., Shapiro, W. A., Morady, F. S., Shen, E. N., Mason, J., Scheinman, M. M., Electrophysiologic testing in patients with the long QT syndrome, Circulation, 71(t): 6371, 1985.
2370. Butt, H., QT-syndrome includes two symptom complexes, Med. Klin., 76 (6) 38-41, 1981.
2376. Campbell, J. W., Frisse, M., Manual of Medical Therapeutics, 24th Edition, Little, Brown & Co., Boston, 79 passim 422, 1983.
2462. Dreifus, L. S., Soffer, J., Drug-induced ventricular arrhythmias: prolonged QT interval, Ann. Emerg. Med., 11(10): 597-8, 1982.
2558. Griggs, R. C., Davis, B. J., Anderson, D. C., Dove, J. T., Cardiac conduction in myotonic dystrophy, Am. J. Med., 59: 37-42, 1975.
2695. Lazzara, R., Anomalous atrioventricular conduction and the pre-excitation syndromes, Bellet's Essentials of Cardiac Arrhythmias, Helfant, R. H., Ed., W. B. Saunders Co., Philadelphia, 182-96, 1980.
2807. Moss, A. J., Schwarz, P. J., Delayed repolarization (QT or QTU prolongation) and malignant ventricular arrhythmias, Mod. Concepts Cardiovase. Dis., 5 1: 85-90, 1982.
2837. O’Callaghan, A. C., Nonnandale, J. P., Morgan, M., The prolonged Q-T syndrome. A review with anaesthetic irnplications and a report of two cases, Anaesth. Intensive Care, 10: 50-5, 1982.
2895. Ratshin, B. A., Hunt, D., Russel, R. O., Rackley, C. E., QT-interval prolongation, paroxysmal ventricular arrhythmias, and convulsive syncope, Ann. Intern. Med., 75: 919-24, 1971.
2951. Shrivastava, S., Tandon, R., The long QT interval: clinical significance and therapeutic implications, Indian J. Chest Dis. Allied Sci., 25: 60-8, 1983.
2957. Singer, P. A., Crarnpton, R. S., Bass, N. H., Familial Q-T prolongation syndrome, Arch Neurol., 31: 64-6, 1974.
3066. Wellens, H. J., Brugada, P., Abdollah, H., Drug therapy of patients with arrhythmias associated with bypass tracts, Clinical Pharmacology of Cardiac Antiarrhythmic Agents: Classical and Current Concepts Reevaluated, Garfein, O. B., Ed., Ann. New York Academy of Science, 432: 272-8, 1984.

Advisory