Hypertrophic cardiomyopathy differential diagnosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Soroush Seifirad, M.D.[2]

Overview

Hypertrophic cardiomyopathy must be differentiated from other diseases that cause [clinical feature 1], [clinical feature 2], and [clinical feature 3], such as [differential dx1], [differential dx2], and [differential dx3].

OR

Hypertrophic cardiomyopathy must be differentiated from [[differential dx1], [differential dx2], and [differential dx3].

Differentiating Hypertrophic cardiomyopathy from other Diseases

Hypertrophic cardiomyopathy must be differentiated from other diseases that cause [clinical feature 1], [clinical feature 2], and [clinical feature 3], such as [differential dx1], [differential dx2], and [differential dx3].

OR

Hypertrophic cardiomyopathy must be differentiated from [differential dx1], [differential dx2], and [differential dx3].

OR

As Hypertrophic cardiomyopathy manifests in a variety of clinical forms, differentiation must be established in accordance with the particular subtype. [Subtype name 1] must be differentiated from other diseases that cause [clinical feature 1], such as [differential dx1] and [differential dx2]. In contrast, [subtype name 2] must be differentiated from other diseases that cause [clinical feature 2], such as [differential dx3] and [differential dx4].

Differentiating Hypertrophic cardiomyopathy from other diseases on the basis of [symptom 1], [symptom 2], and [symptom 3]

On the basis [symptom 1], [symptom 2], and [symptom 3], Hypertrophic cardiomyopathy must be differentiated from [disease 1], [disease 2], [disease 3], [disease 4], [disease 5], and [disease 6].

Cardiomyopathy must be differentiated from athlete heart (which is often confused with HCM on echocardiography), hypertrophy due to hypertension or aortic stenosis; as these have common clinical features, including thickened myocardium on imaging and high QRS voltage on EKGs.

Diseases	Clinical manifestations						Para-clinical findings							Gold standard	Additional findings
	Symptoms			Physical examination
							Lab Findings			Imaging			Histopathology
	Symptom 1	Symptom 2	Symptom 3	Physical exam 1	Physical exam 2	Physical exam 3	Lab 1	Lab 2	Lab 3	Imaging 1	Imaging 2	Imaging 3
Differential Diagnosis 1
Differential Diagnosis 2
Differential Diagnosis 3
Diseases	Symptom 1	Symptom 2	Symptom 3	Physical exam 1	Physical exam 2	Physical exam 3	Lab 1	Lab 2	Lab 3	Imaging 1	Imaging 2	Imaging 3	Histopathology	Gold standard	Additional findings
Differential Diagnosis 4
Differential Diagnosis 5
Differential Diagnosis 6

Overview

The diagnostic imaging modality of choice is echocardiography. There are multiple echocardiographic features that distinguish hypertrophic cardiomyopathy from other conditions that lead to myocardial hypertrophy. In hypertrophic cardiomyopathy, the left ventricle is not dilated, and there is no other condition that would account for the magnitude of hypertrophy. The hypertrophy is often asymmetric.

Differential Diagnosis

HCM must be distinguished from the following disorders:

Athlete's heart

Quite often, HCM can be mistaken for a condition known as athlete’s heart. Both involve growth of the myocardium, however the latter generally is not correlated with incidences of SCD. While HCM can be linked to family history, athlete’s heart arises purely as a function of intense exercise (usually at least an hour a day, everyday. Since the body is operating at high training levels, the heart adapts and grows in order to pump blood more efficiently. Stoppage of exercise for three months generally leads to a decrease in wall/septum thickness in those with athlete’s heart, whereas those with HCM exhibit no decline.

People with athlete’s heart do not exhibit an abnormally enlarged septum, and the growth of heart muscle at the septum and free ventricular wall is symmetrical. The asymmetrical growth seen in HCM results in a less-dilated left ventricle. This in turn leads to a smaller volume of blood leaving the heart with each beat.

	Athlete's Heart	HCM
Septum thickness	<15 mm	>15 mm
Symmetry	Yes (for septum and LV wall)	No (septum much thicker
Family history	None	Possibly
Deconditioning	Reduction within 3 months	None

Several criteria can be used to distinguish these two entities:

The degree of left ventricular wall thickness

• In athlete's heart the LVH is symmetric and less than or equal to 12 mm
• Rarely the LV thickness can be 14-16 mm and this makes it difficult to distinguish from HOCM. Athletes who engage in strength training may develop this pattern, ahtletes who engage in endurance training do not.
• If the degree of thickening is out of proportion to the type and intensity of exercise, this suggests HOCM

The pattern of left ventricular wall thickness

• Athleste's heart is symmetric
• HOCM is more often asymmetric, but may in some cases be symmetric

The left ventricular cavity size

• HOCM has smaller LV cavitary dimensions

Anderson-Fabry disease

(X-linked deficiency of the lysosomal enzyme alphagalactosidase)

Noonan's syndrome

Differentiating hypertrophic cardiomyopathy and valvular aortic stenosis

	Aortic stenosis	Hypertrophic cardiomyopathy
Echocardiography
Aortic valve calcification	Common	No
Dilated ascending aorta	Common	Rare
Ventricular hypertrophy	Concentric LVH	Asymmetric, often involving the septum
Physical examination
Murmur of AI	Common	No
Pulse pressure after PVC	Increased	Decreased
Valsalva maneuver	Decreased intensity of murmur	Increased intensity of murmur
Carotid pulsation	Normal or tardus et parvus	Brisk, jerky, or bisferiens pulse (a collapse of the pulse followed by a secondary rise)