SYNDROME OF PROLONGED Q-T INTERVAL IN PATIENTS WITH CHRONIC GLOMERULONEPHRITIS: POSSIBLE CAUSES OF THE DEVELOPMENT, CORRECTION

THE AIM of the investigation was to elucidate the frequency of the development and to determine the potential causes of the development of the syndrome of prolonged QT interval (SPQTI) in patients with chronic glomerulonephritis (CGN) and to substantiate the possibilities to use betaadrenoblockers of metaprolol (corvitol) and its effectiveness for the correction of QT interval. PATIENTS AND METHODS. The investigation included 70 patients with CGN having the acquired SPQTI (mean age of the patients 38.5±0.9 years, and average duration of the disease 10.4±0.3 years). In 57 of them (81.4%) there were signs of decreased function of the kidneys: 14 patients had I stage CRF, 15 II stage, 28 III stage. The function of the kidney was not impaired in 13 (18.6%) patients. In all the patients ECG in rest was made with the apparatus «Fukuda Densi CardimaxJX 326» (Japan) in 12 standard leads with the registration rate 50 mm/sec. Dispersion of the QT interval (QU) was determined as the disparity between the maximum and minimum intervals Q-T (QU) by the formula: dispersion of the interval QT=QT max Q-T min (ms). RESULTS. It was shown that the average length of the Q-T interval and its dispersion in chronic glomerulonephritis patients increased with progressing renal failure. The potential causes of the development of prolonged QT interval syndrome are: hypertrophy of the left ventricle, clinically significant and asymptomatic dysfunction of the myocardium, dilatation of the left parts of the heart. Metaprolol used in patients with normal function of the kidneys and in the compensated stage of the renal failure promotes a decrease of the average length of the QT interval and its dispersion. CONCLUSION. The average length of the Q-T interval and its dispersion in CGN patients increases with progressing renal failure. Metoprolol (corvitol) decreases the average length and dispersion of the Q-T interval in patents with the saved function of the kidneys and in the initial stage of renal failure.

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