The AHA Guidelines and Scientific Statements Handbook

Chapter 14 Cardiomyopathies

performance, which may be mechanical (e.g., dia-
stolic or systolic dysfunction) or as a primary electri-
cal disease prone to life-threatening arrhythmias.
Indeed, the ion channelopathies have been included
within the present contemporary classifi cation of
primary cardiomyopathies based on the scientifi c
assertion that ion channel mutations alter biophysi-
cal properties and protein structure, thereby creat-
ing structurally abnormal ion channel interfaces and
architecture.

Classifi cation

See Fig. 14.1.
Cardiomyopathies are divided into two major
groups based on predominant organ involvement:
Primary cardiomyopathies (genetic, nongenetic,
acquired) are those solely or predominantly con-
fi ned to heart muscle, and are relatively few in
number. Secondary cardiomyopathies show patho-
logic myocardial involvement as part of a large
number and variety of generalized systemic (multi-
organ) disorders. These systemic diseases associated

with secondary forms of cardiomyopathies have

previously been referred to as “specifi c cardiomy-

opathies” or “specifi c heart muscle diseases” in prior

classifi cations, but that nomenclature has been

abandoned here. The frequency and degree of sec-

ondary myocardial involvement varies considerably

among these diseases, some of which are exceedingly

uncommon, and the evidence of myocardial pathol-

ogy may be sparse and reported in only a few

patients. Since many cardiomyopathies predomi-

nantly involve the heart, but are not necessarily

confi ned to that organ, some of the distinctions

between primary and secondary cardiomyopathy

are necessarily arbitrary, and inevitably rely on judg-

ment concerning the clinical importance and con-

sequences of the myocardial process.

Primary cardiomyopathies

Genetic

Hypertrophic cardiomyopathy (HCM)

HCM is a clinically heterogeneous but relatively

common form of genetic heart disease transmitted

as an autosomal dominant trait (1 : 500 of the general

PRIMARY CARDIOMYOPATHIES

(predominantly involving the heart)

Genetic Mixed* Acquired

DCM

Restrictive

(non-hypertrophied

and non-dilated)

Inflammatory (myocarditis)

Stress-provoked

(“tako-tsubo”)

Peripartum

Tachycardia-induced

Infants of insulin-dependent

diabetic mothers

HCM

ARVC / D

LVNC

Storage

Diseases

PRKAG2

Danon

Conduction Defects

Mitochondrial myopathies

Ion Channel Disorders

LQTS Brugada SQTS CVPT Asian

SUNDS

Fig. 14.1 Primary cardiomyopathies in which the clinically relevant disease processes are solely or predominantly confi ned to the working
myocardium. The conditions have been segregated according to their known genetic or non-genetic etiologies. *At present, familial disease
with a genetic etiology reported in a minority of cases.