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Published on: December 11, 2017
Effect of left ventricular dyssynchrony on cardiac sympathetic activity in heart failure patients with wide QRS
Hidekazu Tanaka1, Kazuhiro Tatsumi, Sei Fujiwara
1Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Japan. tanakah@med.kobe-u.ac.jp
Insights
Cardiac dyssynchrony is linked to reduced cardiac sympathetic activity. (123)I-metaiodobenzylguanidine ((123)I-MIBG) scintigraphy may predict heart failure patients
Area of Science:
- Cardiology
- Nuclear Cardiology
- Heart Failure Management
Background:
- Cardiac dyssynchrony negatively impacts cardiac function.
- The relationship between dyssynchrony and cardiac sympathetic activity requires further elucidation.
Purpose of the Study:
- To investigate the association between cardiac dyssynchrony and cardiac sympathetic activity in heart failure patients.
- To evaluate the predictive value of (123)I-metaiodobenzylguanidine ((123)I-MIBG) scintigraphy for cardiac resynchronization therapy (CRT) response.
Main Methods:
- Fifty heart failure patients undergoing CRT were studied.
- Cardiac sympathetic activity assessed via (123)I-MIBG scintigraphy (delayed heart-to-mediastinum ratio).
- Dyssynchrony measured by radial strain time difference; CRT response defined by end-systolic volume reduction.
Main Results:
- Patients with dyssynchrony exhibited lower (123)I-MIBG H/M ratios compared to those without (1.62 ± 0.31 vs. 1.82 ± 0.36, P<0.05).
- Dyssynchronous patients with H/M ratio ≥1.6 showed high CRT response (94%) and favorable long-term outcomes.
- Non-dyssynchronous patients with H/M ratio <1.6 had poor CRT response (0%) and unfavorable outcomes.
Conclusions:
- Cardiac dyssynchrony is associated with altered cardiac sympathetic activity.
- (123)I-MIBG scintigraphy can potentially predict CRT response in heart failure.
Background:
Dyssynchrony has various detrimental effects on cardiac function, but its effect on cardiac sympathetic activity is not fully understood.
Methods And Results:
We studied 50 heart failure patients who underwent cardiac resynchronization therapy (CRT). Cardiac sympathetic activity was assessed by (123)I-metaiodobenzylguanidine ((123)I-MIBG) scintigraphy as the delayed heart-to-mediastinum ratio (H/M ratio). Echocardiography was performed before and 7 months after CRT, and response was defined as a ≥15% decrease in end-systolic volume. Dyssynchrony was determined by the time difference between the anteroseptal-to-posterior wall using speckle-tracking radial strain (≥130 ms predefined as significant). H/M ratio in patients with dyssynchrony was less than that in patients without dyssynchrony (1.62 ± 0.31 vs. 1.82 ± 0.36, P<0.05), even though ejection fraction was not significantly different (24 ± 6% vs. 25 ± 7%). Patients with dyssynchrony and H/M ratio ≥1.6 had a higher frequency of response to CRT (94%) and favorable long-term outcome over 3.0 years. In contrast, patients without dyssynchrony and H/M ratio <1.6 were more likely to show a lower frequency of response to CRT (0%) and unfavorable long-term outcome after CRT.
Conclusions:
Dyssynchrony is associated with cardiac sympathetic activity, and (123)I-MIBG scintigraphy may be valuable for predicting the response to CRT.
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