ABSTRACT
Background: Neurogenic stunned myocardium (NSM) is a devastating complication of subarachnoid hemorrhage (SAH). The most widely accepted mechanism in the pathogenesis
of NSM and takotsubo cardiomyopathy is catecholamine-mediated direct myocardial injury. The aim of this study is to examine if there is any effect of sym- pathetic overactivity of the stellate ganglions on myocar- dial tissues, secondary to vagal complex degeneration in SAH-induced NSM.
Materials and methods: This study was conducted on 25 New Zealand female rabbits. After the examination, all animals were assigned into 3 groups randomly: a control group (n=5), a sham group (n=5), and a study group (n=15) that was subjected to experimental SAH with double injection of blood into the cisterna magna. After 7 animals exhibited NSM, all animals were killed. Their brains, vagal complexes, stellate ganglions, and hearts were extracted and examined by histopathologic methods. Degenerated nodose ganglion neurons and stellate gan- glion neuron densities were compared with degenerated myocardial tissue/normal myocardial tissue ratios, and the results were analyzed with the Mann-Whitney U test.
Results: Three rabbits in the study group died imme- diately after the second injection of blood. NSM developed in 7 animals after 1 to 5 days, which was diagnosed with transthoracic echocardiography. Interestingly, the animals that developed NSM had more stellate ganglia neurons and more degenerated neuron densities of nodose ganglia
(P < 0.001).
Conclusions: NSM and takotsubo cardiomyopathy may be induced by vagal complex degeneration and sympathetic overactivity, which originated from more neurons, including stellate ganglia and more degenerated neuron densities of nodose ganglia.