[Increased QRS voltage during dehydrating].

AIM

To assess QRS voltage changes with lower total amount of biological fluids under ultrafiltration during hemodialysis.

MATERIALS AND METHODS

The study included 14 patients with chronic renal failure. An average of 2.5 +/- 0.24 liters of fluid were removed during a session. 12-lead standard ECG was continuously recorded by means of a computer-aided cardiac recorder throughout the session of hemodialysis. Changes in the amplitude of QRS waves were analyzed in each lead.

RESULTS

Elevated QRS voltage was most pronounced in the anterior chest leads (v1-v4). Moreover, the potentials corresponding to the propagation of a predominant excitation front over the cardiac surface facing both the anterior chest wall--QRS+ (R wave) and the posterior chest wall--ORS-(S or Q waves) increased in most cases. Voltage changes in these leads were observed in 90% of patients, the amplitude of the waves being increased by more than 0.5 mV.

CONCLUSION

During dehydration, lower chest tissue electroconductivity may cause a considerable increase in QRS voltage. This should be kept in mind while analyzing ECG data during both a session of hemodialysis and antihypertensive therapy resulting in some fluid loss, as well as in the treatment of cardiac and renal failure, leading to diminished concomitant edemas.