[Effects of myocardial stretching on excitation frequencies determined by spectral analysis during ventricular fibrillation].
OBJECTIVE
The aim of this study was to analyze the effects of myocardial stretching on excitation frequencies, as determined by spectral analysis, during ventricular fibrillation.


METHODS
In 12 isolated rabbit heart preparations, ventricular activation during ventricular fibrillation was recorded with multiple electrodes. Recordings were obtained before, during and after ventricular dilatation produced with an intraventricular balloon. The dominant frequency of the signals obtained with each of the electrodes was determined by spectral analysis.


RESULTS
During the control phase, the mean, minimum and maximum dominant frequencies were, respectively, 14.3 1.7, 12.5 1.7, and 16.2 1.4 Hz, and the average difference between the maximum and minimum frequencies was 3.6 2.1 Hz. This difference was over 4 Hz in four cases, and in no case did it exceed 8 Hz. During ventricular stretching, the mean dominant frequency increased significantly (21.1 6.1 Hz; p < 0.0001), as did the minimum values (14 2.6 Hz; p < 0.05) and especially the maximum values (26.6 7.7 Hz; p < 0.0001). The difference between the maximum and minimum frequencies (12.6 6.4 Hz; p < 0.001) was over 4 Hz in all cases except one, and over 8 Hz in 9 cases. The maximum values were distributed heterogeneously during ventricular stretching. Upon suppressing ventricular stretching, the dominant frequency did not differ from controls.


CONCLUSIONS
Myocardial frequency maps during ventricular fibrillation show limited variations in the dominant frequency of the signals recorded in the lateral wall of the left ventricle. During stretching, the patterns were heterogeneous, due mainly to the marked increase in the maximum dominant frequency. In the experimental model used, the effects of stretching remitted after suppressing ventricular dilatation.
Chorro
Francisco J
FJ
Servicio de Cardiología del Hospital Clínico Universitario de Valencia. España. francisco.j.chorro@uv.es
Millet
José
J
Ferrero
Angel
A
Cebrián
Antonio
A
Cánoves
Joaquín
J
Martínez
Alvaro
A
Mainar
Luis
L
Porres
Juan Carlos
JC
Sanchis
Juan
J
López Merino
Vicente
V
Such
Luis
L
D000818:Animals; D004594:Electrophysiology; D006321:Heart / Q000503:physiopathology*; D066298:In Vitro Techniques; D009206:Myocardium; D011817:Rabbits; D014693:Ventricular Fibrillation / Q000503:physiopathology*