Analysis of Hemodynamic Related Changes in High Frequency Content of QRS Complex in Working Isolated Rabbit Heart

Abstract

Aim: High frequency content of QRS complex (HF-QRS) is thought to be related to local conduction velocity (CV). There also exists the evidence suggesting the coupling between CV and mechanical stretch via socalled mechano-electric feedback. The aim of this study was to investigate possible relationship between left ventricular (LV) load and the most common HF-QRS parameters. Methods: Six isolated rabbit hearts in working mode underwent an experimental protocol consisting of upward and downward steps in preload (8-11 cmH 2 O). Eight unipolar pseudo-ECGs, left atrial pressure, and flow rate were recorded at f s =10 kHz and 16-bit resolution. QRS complexes from hemodynamically stable experiment phase were clustered, aligned, and decomposed into 3 HF-QRS bands followed by the assessment of power envelope RMS, the tallest peak value and its position. Results: No statistically significant changes associated with LV load alteration were observed in HF-QRS parameter. Conclusion: No evidence of load dependent changes in conduction velocity was found in the study. However, HF signal may represent a complex spatial depolarization behavior. Low sensitivity of used metrics should also be taken into consideration.

Golden Standard or Obsolete Method? Review of ECG Applications in Clinical and Experimental Context

“… Novotna et al (2017) investigated the usefulness of simply derived and robust features based on high-frequency components of QRS complexes (the maximal peak of QRS envelope, distance from QRS envelope maxima to R peak, and root mean square of the QRS area) to evaluate the conduction velocity in the working isolated rabbit heart under induced hemodynamic changes.…”