13
Table 7. Examples of Factors Implicating Possible Genetic
Cardiomyopathy
Phenotypic Category
Patient or Family
Member Phenotypic
Finding*
Ask Specifically About
Family Members* With
Cardiac morpholog y Marked LV hypertrophy Any mention of
cardiomyopathy, enlarged
or weak heart, HF.
Document even if
attributed to other
causes, such as
alcohol or peripartum
cardiomyopathy
LV noncompaction
Ventricular thinning or
fatty replacement on
imaging or biopsy
Findings on 12-lead ECG Abnormal high or low
voltage or conduction, and
repolarization, altered RV
forces
Recurrent syncope, long
QT or Brugada syndrome
Dysrhythmias Frequent NSVT or very
frequent PVCs
ICD
Sudden death attributed
to "massive heart attack"
without known CAD
Unexplained fatal event
such as drowning or single-
vehicle crash
Sustained ventricular
tachycardia or fibrillation
Early onset AF "Lone" AF before age 65
years
Early onset conduction
disease
Pacemaker before age 65
years
Extracardiac features • Skeletal myopathy
• Neuropathy
• Cutaneous stigmata
• Other possible
manifestations of
systemic syndromes
Any known skeletal muscle
disease, including mention
of Duchenne and Becker's,
Emory-Dreifuss limb-
girdle dystrophy
Systemic syndromes:
• Dysmorphic features
• Mental retardation
• Congenital deafness
• Neurofibromatosis
• Renal failure with
neuropathy
* Note that genetic cause is more likely when the person is younger at the onset of events.
However, the cardiac morpholog y and peripheral manifestations of hereditary amyloidosis
may present in later life, unlike most other inherited cardiomyopathies
