MARON
AND MCKENNA et al., ACC/ESC Expert Consensus Document on Hypertrophic
Cardiomyopathy
JACC 2003; 42:
000-000
American
College of Cardiology/European Society of Cardiology Clinical
Expert Consensus Document on Hypertrophic Cardiomyopathy
A
Report of the American College of Cardiology Foundation Task
Force on Clinical Expert Consensus Documents and the European
Society of Cardiology Committee for Practice Guidelines
Nomenclature,
Definitions, and Clinical Diagnosis
The
clinical diagnosis of HCM is established most easily and reliably
with two-dimensional echocardiography by demonstrating left
ventricular hypertrophy (LVH) (typically asymmetric in distribution,
and showing virtually any diffuse or segmental pattern of
left ventricular [LV] wall thickening) 36. Left ventricular
wall thickening is associated with a nondilated and hyperdynamic
chamber (often with systolic cavity obliteration) in the absence
of another cardiac or systemic disease (e.g., hypertension
or aortic stenosis) capable of producing the magnitude of
hypertrophy evident, and independent of whether or not LV
outflow obstruction is present 1,5,7,36. Although the usual
clinical diagnostic criteria for HCM is a maximal LV wall
thickness greater than or equal to 15 mm, genotype-phenotype
correlations have shown that virtually any wall thickness
(including those within normal range) are compatible with
the presence of a HCM mutant gene 6,17,19,63-65. Mildly
increased LV wall thicknesses of 13 to 14 mm potentially due
to HCM should be distinguished from certain extreme expressions
of the physiologically-based athlete’s heart 66-68.
The advent of contemporary magnetic resonance imaging that
provides high-resolution tomographic images of the entire
LV may represent an additional diagnostic modality 69 particularly
in the presence of technically suboptimal echocardiographic
studies or when segmental hypertrophy is confined to unusual
locations within the LV wall. Since the modern description
by Teare in 1958 12, HCM has been known by a confusing array
of names that largely reflect its clinical heterogeneity,
relatively uncommon occurrence in cardiologic practice, and
the skewed experience of early investigators. This problem
in nomenclature has been an obstacle to general recognition
of the disease within the medical and non-medical community.
Hypertrophic cardiomyopathy (or HCM) is now widely accepted
as the preferred term 7 because it describes the overall
disease spectrum without introducing misleading inferences
that LV outflow tract obstruction is an invariable feature
of the disease, such as is the case with hypertrophic obstructive
cardiomyopathy , muscular subaortic stenosis 71, or
idiopathic hypertrophic subaortic stenosis 72. Indeed, most
patients with HCM do not demonstrate outflow obstruction under
resting (basal) conditions, although many may develop dynamic
subaortic gradients of varying magnitude with provocative
maneuvers or agents 7,13,41,72-77. Of note, even though
the absence of obstruction (at rest) is common, both in patients
with and without symptoms, most treatment modalities have
targeted those symptomatic HCM patients with outflow obstruction
41,43-49,78-108.
©
2003 by the American College of Cardiology and the European
Society of Cardiology |
