Abstract 12396: Elevated Myocardial Oxidative Stress Induced by Catecholamines Related to Transient Left Ventricular Dysfunction in Patients With Takotsubo Cardiomyopathy
Background: The pathophysiology of takotsubo cardiomyopathy (TC) remains elusive. Here, we investigated how myocardial oxidative stress influenced myocardial dysfunction in patients with TC compared with acute anteroseptal myocardial infarction (AMI).
Methods and Results: In 14 patients with TC and 10 patients with AMI, who admitted to our hospital (Killip 3 and 4), ECG, echocardiography, cardiac catheterization, serial measurements of plasma catecholamines, urinary (U) 8-hydroxy-2’-deoxyguanosine (8-OHdG) as a marker of oxidative DNA damage and CPK were performed for two weeks from onset. In all cases of TC, dual scintigraphy of 201Tl and 123I-meta-iodobenzylguanidine (MIBG) was performed at 7th hospital day, to examine the damage of the sympathetic nervous system of heart and the myocardial perfusion. The plasma norepinephrine (NE) level (pg/ml) on admission (1st day) were 2-times higher in TC than in AMI (TC; 1714±556 vs. AMI; 886±445, p<0.05), although the max CPK value in TC was significantly lower than that in AMI. The NE level was decreased to nearly normal range in AMI at 7rd, while it was still 2-times elevated in TC for a week. Blood sampling from coronary sinus (CS) and aorta (Ao) showed that serum 8-OHdG level in CS was significantly higher than that in Ao, indicating that 8-OHdG was produced from cardiac tissue. The U-8OHdG level (ng/mg Cr; normal range:<10.0) was significantly decreased to almost normal range after percutaneous coronary intervention for left anterior descending artery in AMI (1st day: 27.5±7.6 vs. 7th day: 10.4±3.5, p<0.01), while the elevation of U-8OHdG was sustained in parallel with the profile of plasma NE level (1st day: 49.5±12.6 vs. 7th day: 22.5±5.8, p<0.01). Dual scintigraphy findings showed that sympathetic nervous injury of heart was much larger than myocardial perfusion damage in TC. Interestingly, echocardiography findings revealed that LV dysfunction in TC was improved in parallel with a decrease of U-8OHdG within 2 weeks.
Conclusion: These findings suggest that the sustained myocardial oxidative stress induced by catecholamines may relate to transient LV dysfunction. Urinary 8-OHdG level, therefore, may provide relevant functional and tissue information that might resolve the pathophysiology of TC.
- © 2012 by American Heart Association, Inc.