The AHA Guidelines and Scientific Statements Handbook

The AHA Guidelines and Scientifi c Statements Handbook

Myocarditis typically evolves through active,
healing and healed stages, characterized progres-
sively by infl ammatory cell infi ltrates leading to
interstitial edema and focal myocyte necrosis and
ultimately replacement fi brosis. These pathologic
processes create an electrically unstable substrate
potentially predisposing to the development of ven-
tricular tachyarrhythmias and even sudden death. In
some instances, an episode of viral myocarditis (fre-
quently subclinical) can trigger an autoimmune
reaction that causes immunologic damage to the
myocardium or cytoskeletal disruption, culminating
in DCM with LV dysfunction.

Stress (“tako-tsubo”) cardiomyopathy
Stress cardiomyopathy, fi rst reported in Japan as
“tako-tsubo,” is a recently described clinical entity
characterized by acute, but rapidly reversible LV sys-
tolic dysfunction in the absence of atherosclerotic
coronary artery disease, and triggered by profound
psychological stress. This distinctive form of ven-
tricular stunning typically affects older women and
preferentially involves the distal portion of the
LV chamber (“apical ballooning”), with basal
hypercontractility. Although presentation often
mimics ST-segment elevation myocardial infarc-
tion, outcome is favorable with appropriate medical
therapy.

Secondary cardiomyopathies
The most important secondary cardiomyopathies
are provided in Table 14.1. This list is not, however,

intended to represent an exhaustive and complete

tabulation of the vast number of systemic conditions

reported to involve the myocardium, but rather is

limited to the most common of these diseases fre-

quently associated with a cardiomyopathy.

Recent ESC classifi cation of

cardiomyopathies

Another classifi cation of cardiomyopathies has

recently been promoted under the auspices of the

European Society of Cardiomyopathy and European

Society of Cardiology (ESC) Working Group on

Myocardial and Pericardial Diseases, apparently in

response to the AHA classifi cation [2] (Fig. 14.2).

The ESC document is designed based on the premise

that contemporary understanding of the cardiomy-

opathies is only confused by genetic diagnostic

“labels.” The ESC working group segregates diseases

based on “specifi c morphological and functional

phenotypes,” in effect expanding the 1995 World

Health Organization Classifi cation scheme [3],

while abandoning the distinction between primary

and secondary cardiomyopathies used by

AHA.

Consequently, the ESC classifi cation is advanced

by the authors as (in some undefi ned way) more

effective for routine clinical practice. In contrast, the

AHA document is criticized by ESC as most suited

for research purposes. However, this latter charac-

terization would not seem to be justifi ed, given the

similarities of the two documents with respect to

clinical diagnostic defi nitions, and even the classifi -

Idiopathic

Cardiomyopathies

HCM DCM ARVC RCM Unclassified

Familial/Genetic Non-familial/Non-genetic

Unidentified Disease sub-type* Disease sub-type*

gene defect

Fig. 14.2 Summary of proposed ESC cardiomyopathy classifi cation system. ARVC, arrhythmogenic right ventricular cardiomyopathy; DCM,
dilated cardiomyopathy; HCM, hypertrophic cardiomyopathy; RCM, restrictive cardiomyopathy.