Key result
Congenital long-QT syndrome was associated with a selective reduction in sympathetic drive to muscle blood vessels, including a lower muscle sympathetic nerve activity burst rate (P=0.008).
Why the study?
Does congenital long-QT syndrome alter sympathetic nerve activity compared to healthy controls?
Case-Control (n=24)
Does congenital long-QT syndrome alter sympathetic nerve activity compared to healthy controls?
p-value: p=0.008
Congenital LQTS is associated with a selective reduction in sympathetic drive to muscle blood vessels and potentially the heart, suggesting altered autonomic regulation.
Supports hypothesis of autonomic dysregulation in congenital LQTS; leaves open its role in arrhythmia risk and therapeutic targeting.
BACKGROUND: Patients with congenital long-QT syndrome (LQTS) are susceptible to life-threatening arrhythmias. The sympathetic nervous system may have an important triggering role for cardiovascular events in LQTS. We therefore examined measurements of sympathetic neural traffic in patients with LQTS and matched control subjects. METHODS AND RESULTS: Twelve patients with congenital LQTS and 12 healthy volunteers matched for age, sex, and body mass index were studied. Heart rate, respiration, blood pressure, and sympathetic nerve activity to the skeletal muscle blood vessels (muscle sympathetic nerve activity) and to the skin (skin sympathetic nerve activity) were monitored and recorded continuously. Resting heart rate (P=0.03), muscle sympathetic nerve activity burst rate (P=0.008), and burst incidence (P=0.02) were lower in patients with LQTS than in control subjects. However, skin sympathetic nerve activity was very similar in patients with LQTS and control subjects. Spectral analysis of RR variability showed a decreased low-frequency component, an increased high-frequency component, and a decrease in the ratio of the low-frequency component to the high-frequency component in patients with LQTS (P=0.01). CONCLUSIONS: LQTS is associated with a selective reduction in sympathetic drive to muscle blood vessels and perhaps also to the heart.
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Shamsuzzaman et al. (2003) conducted a case-control in Congenital long-QT syndrome (n=24). Congenital long-QT syndrome vs. Healthy volunteers was evaluated on Muscle sympathetic nerve activity burst rate (p=0.008). Congenital long-QT syndrome was associated with a selective reduction in sympathetic drive to muscle blood vessels, including a lower muscle sympathetic nerve activity burst rate (P=0.008).
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