32
Table 5. Clinical scenarios for the management of arrhythmias
in EDMD and LGMD1B
Clinical scenario
LGMD1B
4. A 42-year-old woman is admitted after a transient episode of sudden loss of
consciousness. She has a history of ankle contractures since adolescence. Over
the past 5 years, she has developed progressive muscle weakness with difficulty
climbing stairs. She had an older sister with similar muscular disease and heart
disease who died at age 38 years after complications of a stroke. Genetic testing
revealed a missense mutation in LMNA. Her ECG revealed sinus tachycardia with
a PR interval of 300 ms, incomplete RBBB, and left axis deviation. Transthoracic
echocardiogram revealed left ventricle dilation with reduced function and an
estimated LVEF of 40%. Ambulatory ECG recording revealed atrial tachycardia
with 3:1 and 4:1 conduction.
5. A 35-year-old man with LGMD1B presents to the clinic to discuss the possibility
of pacemaker placement. He was suspected to have LGMD1B when he was
15 years old, after developing proximal muscle weakness, in the absence of
contractures. Genetic testing confirmed an LMNA mutation (1q11-21 locus).
Since that time, he has had progressive lightheadedness. His 12-lead ECG and
recent Holter monitoring are normal, and transthoracic echocardiography was
unremarkable.
(cont'd)
Emery-Dreifuss and Limb-girdle Type 1B
Muscular Dystrophy
