Spontaneous atrial fibrillation initiated by tyramine in canine atria with increased sympathetic nerve sprouting.

ABSTRACT:

Background

Chronic left ventricular myocardial infarction (LVMI) promotes atrial and pulmonary veins (PV) sympathetic nerve sprouting.

Objectives

To test the hypothesis that sympathetic stimulation with tyramine initiates atrial fibrillation (AF) by early after depolarization (EAD)-mediated triggered activity at the left atrial PV (LAPV) junction.

Methods

LVMI was created in 6 dogs and 6 dogs served as controls. Six to 8 weeks later the activation pattern of the isolated LAPV was optically mapped using dual voltage and intracellular Ca(+2) (Ca(i) (2+) )-sensitive epifluorescent dyes before and after tyramine (5 μM) perfusion.

Results

Tyramine initiated spontaneous AF in 5 of 6 atria but none in the control group (P < 0.01). The AF was initiated by late phase 3

SUBMITTER: Numata A 

PROVIDER: S-EPMC4364657 | biostudies-literature | 2012 Apr

REPOSITORIES: biostudies-literature