Endomyocardial biopsy was taken, H+E examination revealed non-specific findings. Electrophysiologic study excluded the presence of accessory pathways. Following mild doses of beta-blocker treatment, conduction disease was unmasked showing bradycardia and second degree a-v block (Wenckebach type) and episodes of atrial fibrillation with slow ventricular response. The patient received DDD pacemaker. Within 4 years the patient developed progressive decrease of exercise tolerance, signs of heart failure; his LVEF dropped to <20%. Following poor response to full conventional medical therapy, the patient received heart transplant.
Following HTX, the patient came asking for genetic studies for his family, especially for his offspring. Cardiac examination including ecg and echocardiography showed no significant abnormality. A nonsense mutation Y481Stop was found in the LMNA in the proband and in three of his children. Following the genetic diagnosis, Holter 24h ecg monitoring was performed in all mutation carriers. The examination revealed two VE triplets in an 18-year-old girl, episodes of advanced II degree a-v block in a13- year-old girl and nsVT (a burst of 10 VE beats) in an 11-year-old boy. All three children were asymptomatic, feeling healthy.
Pedigree of the family
Dilated cardiomyopathy (DCM) is defined by the presence of left ventricular dilatation and left ventricular systolic dysfunction in the absence of abnormal loading conditions (hypertension, valve disease) or coronary artery disease sufficient to cause global systolic impairment . With the new European classification, we are prompted to think about familial vs nonfamilial disease; in this particular family the familial background is unlikely, the proband’s father died of heart attack at the age of 68 years and his mother is treated because of hypertension.
The course of the disease in the proband is typical of laminopathy. First symptoms: episodes of supraventricular arrhythmia, associated with a-v block were followed by steadily decreasing LV contractility, requiring heart transplantation [2, 3]. Mildly dilated left ventricle with severely depressed LV contractility, representing mildly dilated congestive cardiomyopathy, not present in the proband, is also a common presentation of laminopathy. Subclinical skeletal muscle involvement with elevated sCPK level may be present. DCM patients with laminopathy have poor prognosis. Heart involvement may belong to the spectrum of overlapping laminopathies characterized by the coexistence of several tissue involvements such as striated muscles with partial lipodystrophy [4, 5] and striated muscle with peripheral nerves and leuconychia . Besides, other isolated cardiac conditions, such as apical left ventricular aneurysm without atrio-ventricular block , early atrial fibrillation  and left ventricular noncompaction are also linked to LMNA gene mutations .
A second question is much more difficult to answer. Accumulating evidence shows that LMNA mutation carriers are at increased risk of sudden death despite pacemaker implantation [10, 11]. Consequently, all mutation carriers should be considered as candidates for ICD implantation. The decision, however, is very difficult to make in teenagers, especially feeling healthy. The risk of death increases with age, little is known, however, about sudden death at young age in this subgroup. In this family, the eldest mutation carrier, following second Holter monitoring (showing 2 VE triplets and several episodes of sinus pauses during daily activities) received ICD. The mutation carrier with episodes of advanced II degree a-v block received a DDD pacemaker, and is considered for replacement with ICD. The youngest boy remains asymptomatic, receives a small dose of beta-blocker and undergoes regular follow-up with Holter ecg monitoring.
By Dr Zofia Bilinska. 1st Dept. Coronary Artery Disease and Outpatient Clinic, Institute of Cardiology, Warsaw, Poland
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