The severity of ventricular arrhythmia correlates with the extent of myocardial sympathetic denervation, but not with myocardial fibrosis extent in chronic Chagas cardiomyopathy

To investigate the correlation between the extent of myocardial sympathetic denervation and fibrosis and the presence of degrees of severity of ventricular arrhythmias in chronic chagas cardiomyopathy (ccc). forty-three ccc patients with left ventricular ejection fraction (lvef) ≥ 35% were divided into three groups: svt group—presenting sustained ventricular tachycardia (svt) (n = 15), nsvt group—exhibiting episodes of non-svt (nsvt) on 24-h holter monitoring (n = 11), and control group—exhibiting neither svt nor episodes of nsvt (n = 17). the patients underwent spect imaging for myocardial sympathetic innervation with 123iodine-mibg (mibg) and myocardial perfusion with 99mtc-sestamibi (mibi) for the evaluation of regional myocardial fibrosis. the summed rest perfusion scores were similar in the three groups. the summed difference score between mibg and mpi images, which evaluated the extent of denervated but viable myocardium, was significantly higher in svt group (20.0 ± 8.0) as compared with the control group (2.0 ± 5.0, p < .0001) and with the nsvt group (11.0 ± 8.0, p < .05). the occurrence of ventricular arrhythmias of different degrees of severity correlates quantitatively with the extent of cardiac sympathetic denervation, but not with the extent of fibrosis, suggesting that myocardial sympathetic denervation plays a major role in triggering ventricular arrhythmia in ccc.