Electrical Rhythms Revealed by Harmonic Analysis of a High-Resolution Cardiogram.

The front-end low-noise electronic amplifiers and high-throughput computing systems made it possible to record ECG with a high resolution in the low-frequency range including the respiration and Mayer frequencies and to analyze ECG with digital filtering technique and harmonic analysis. These tools yielded ECG spectra of narcotized rats, which contained the characteristic pulsatile triplets and pentaplets with splitting constant equal to respiration rate, as well as the peaks at respiration and Mayer frequencies. The harmonic analysis of ECG determined the frequency parameters employed to tune the software bandpass filters, which revealed the respiratory (R) and Mayer (M) waves in the time domain with the amplitudes of 20-30 µV amounting to 5% ECG amplitude. The depolarizing myorelaxant succinylcholine chloride capable to trigger various types of arrhythmias, transiently increased R-wave, inhibited M-wave, and provoked a negative U-wave within a heartbeat ECG cycle synchronously with inspiration. It is hypothesized that M-, R-, and U-waves in ECG reflect cardiotropic activity of autonomic nervous system. The respective spectral peaks in ECG can be employed to assess intensity of sympathetic and parasympathetic cardiotropic influences, their balance, and the risk of arrhythmias.

[Hydrodynamic method for diagnosing impaired patency of the lacrimal tract].

A hydrodynamic method has been developed, which is based on measurement of the pressure of a certain amount of the fluid passing through the patient's lacrimal tract for a given period. Pressures were determined in 194 healthy volunteers (338 eyes). Three hundred and seventy-six patients (752 eyes) with impaired lacrimation were examined. The examinations have shown that the method provides a way of objectively defining the degree of dacryostenosis, which makes it possible to further use adequate therapy and to monitor its efficiency.