Rinsho Shinkeigaku (Clinical Neurology)

Symposium 3

Management of atrioventricular conduction abnormalities in myotonic dystrophy

Takuhisa Tamura

Department of Neurology, National Hospital Organization Higashisaitama Hospital

Sudden death is a serious problem in patients with myotonic dystrophy. Atrioventricular blocks (AVBs) and tachyarrhythmias are regarded as a cause of the cardiac sudden death. The increase of QRS width and the deviation of electrical axis are rather important because the main lesion of AVB is located in His-Purkinje system, while the prolongation of PR interval attracts our attention for AVB. The measurement of His-ventricle (HV) interval is indispensable to cardiac electrophysiological testing for the detection of His-Purkinje abnormalities. We measured "HV interval" (BHV) noninvasively, using His bundle potential recorded from the body surface by signal-averaged electrocardiogram. As a result, BHV correlated with QRS width and electrical axis (r=0.769, p<0.0001; r=-0.713, p=0.0004, respectively). Pacemaker implantation (PMI) is performed for the treatment of bradyarrhythmias based on the guideline of each country. Some reports revealed that prophylactic PMI did not improve the prognosis of asymptomatic case with severe muscle involvement, even if HV interval was over 70ms. It is important to assess PMI indication in each case, deliberating the extra-cardiac complications and prognosis.
Full Text of this Article in Japanese PDF (170K)

(CLINICA NEUROL, 52: 1261|1263, 2012)
key words: myotonic dystrophy, atrioventricular block, HV interval, signal-averaged electrocardiogram, pacemaker implantation

(Received: 25-May-12)