Myocardial tissue velocity reduction is correlated with clinical neurologic severity in myotonic dystrophy

Area of Science:

• Cardiology
• Neurology
• Genetics

Background:

• Myotonic dystrophy (MD) is associated with a 15% mortality rate from ventricular arrhythmias.
• Left ventricular (LV) dysfunction and heart failure are infrequently documented in MD patients.
• Subclinical cardiac impairment in MD warrants investigation.

Purpose of the Study:

• To prospectively assess subclinical left ventricular (LV) contractility impairment in MD patients without known heart failure.
• To evaluate LV function using echocardiography and tissue Doppler imaging.
• To correlate cardiac abnormalities with neurologic severity and CTG trinucleotide repeat length.

Main Methods:

• Prospective evaluation of 22 MD patients without known heart failure and 22 age-matched healthy controls.
• Conventional 2-dimensional echocardiography and tissue Doppler imaging were employed.
• Analysis included LV ejection fraction, peak systolic velocities, and mean LV velocities.

Main Results:

• No significant difference in LV ejection fraction between MD patients and controls (p = 0.86).
• Significantly lower peak systolic velocities in MD patients compared to controls in basal lateral, basal septal, and mitral annulus-lateral segments (p < 0.005).
• Reduced mean LV velocities observed in MD patients (p < 0.002).
• Peak systolic velocities inversely correlated with neurologic severity (r = -0.51, p = 0.014) but not trinucleotide repeat length.

Conclusions:

• MD patients without known heart failure exhibit reduced myocardial tissue velocities.
• The degree of myocardial velocity reduction is associated with neurologic severity in MD.
• Tissue Doppler imaging can detect subclinical cardiac impairment in MD.