Left ventricular geometry immediately following defibrillation

Shock-induced relaxation

Amy Curry, Vijaya Ramanathan, Brent K. Hoffmeister, Robert A. Malkin

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

A previous two-dimensional (2D) ultrasound study suggested that there is relaxation of the myocardium after defibrillation. The 2D study could not measure activity occurring within the first 33 ms after the shock, a period that may be critical for discriminating between shock- and excitation-induced relaxation. The objective of our study was to determine the left ventricular (LV) geometry during the first 33 ms after defibrillation. Biphasic defibrillation shocks were delivered 5-50 s after the induction of ventricular fibrillation in each of the seven dogs. One-dimensional, short-axis ultrasound images of the LV cavity were acquired at a rate of 250 samples/s. The LV cavity diameter was computed from 32 ms before to 32 ms after the shock. Preshock and postshock percent changes in LV diameter were analyzed as a function of time with the use of regression analysis. The normalized mean pre- and postshock slopes (0.2 ± 2.2 and 3.3 ± 7.9% per 10 ms) were significantly different (P < 0.01). The postshock slope was positive (P < 0.005). Our results confirm that the bulk of the myocardium is relaxing immediately after defibrillation.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume284
Issue number3 53-3
StatePublished - Mar 1 2003

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Shock
Myocardium
Ventricular Fibrillation
Regression Analysis
Dogs

All Science Journal Classification (ASJC) codes

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

Cite this

Left ventricular geometry immediately following defibrillation : Shock-induced relaxation. / Curry, Amy; Ramanathan, Vijaya; Hoffmeister, Brent K.; Malkin, Robert A.

In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 284, No. 3 53-3, 01.03.2003.

Research output: Contribution to journalArticle

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