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

About 15% of patients with myotonic dystrophy (MD) die of ventricular arrhythmias, but few have documented left ventricular (LV) dysfunction and heart failure. This study prospectively evaluated a group of patients with MD without known heart failure to assess whether there is subclinical impairment of LV contractility using conventional 2-dimensional echocardiography and tissue Doppler imaging, and to correlate any abnormalities found with the degree of neurologic severity and cytosine-thymine-guanine trinucleotide repeat length. Twenty-two patients with MD without known heart failure were evaluated and compared with 22 healthy, age-matched controls. The patients with MD and control subjects did not differ with respect to LV ejection fraction (60 ± 5% vs 60 ± 4%, respectively, p = 0.86). However, peak systolic velocities were significantly lower in subjects with MD compared with controls in the basal lateral (6.1 ± 2.6 vs 8.2 ± 2.0 cm/s, p <0.005), basal septal (5.0 ± 1.1 vs 6.3 ± 1.1 cm/s, p <0.0003), and mitral annulus-lateral segments (7.6 ± 1.9 vs 9.2 ± 1.9 cm/s, p = 0.007). Mean LV velocities were also lower in subjects with MD (6.2 ± 1.3 vs 7.5 ± 1.1 cm/s, p <0.002). In subjects with MD, the peak systolic velocities correlated inversely with neurologic severity (r = −0.51, p = 0.014) but not with trinucleotide repeat length. In conclusion, patients with MD without known heart failure were found to have reduced myocardial tissue velocities; the degree of velocity reduction correlated with their neurologic severity.