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Essentials of Diagnosis
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May present with dyspnea, chest pain, syncope
Though left ventricular (LV) outflow gradient is classic, symptoms are primarily related to diastolic dysfunction
Echocardiogram is diagnostic; any area of LV wall thickness > 1.5 cm defines the disease
Increased risk of sudden death
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General Considerations
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Hypertrophic cardiomyopathy (HCM) is noted when there is LV hypertrophy (LVH) unrelated to any pressure or volume overload
The LV is usually more involved than the right ventricle (RV), and the atria are frequently significantly enlarged
Increased wall thickness
Reduces LV systolic stress
Increases the ejection fraction (EF)
Can result in an "empty ventricle" at end-systole
The consequence of the hypertrophy is elevated LV diastolic pressures rather than systolic dysfunction
The interventricular septum may be disproportionately involved (asymmetric septal hypertrophy)
However, in some cases, the hypertrophy is localized to the mid-ventricle or to the apex
LV outflow obstruction is worsened by
Increased myocardial contractility (sympathetic stimulation, digoxin, and postextrasystolic beat)
Decreased LV filling (Valsalva maneuver, peripheral vasodilators)
LV outflow obstruction, however, may not be present
Patients usually present in early adulthood
HCM in older adults
Elite athletes may demonstrate hypertrophy that can be confused with HCM, but generally diastolic dysfunction is not present in the athlete and this finding helps separate pathologic disease from athletic hypertrophy
Pregnancy results in an increased risk in patients with symptoms or outflow tract gradients of > 50 mm Hg
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Dyspnea
Chest pain
Syncope, typically postexertional
Arrhythmias
Features on physical examination include
The jugular venous pressure may reveal a prominent a wave due to reduced RV compliance
In cases with LV outflow obstruction, a loud systolic murmur is present along the left sternal border that increases with upright posture or Valsalva maneuver and decreases with squatting; these maneuvers help differentiate HCM from aortic stenosis
In HCM, reducing the LV volume increases the outflow obstruction and the murmur intensity
In valvular aortic stenosis, reducing the stroke volume across the valve decreases the murmur
Mitral regurgitation is frequently present
HCM in older adults
Mitral annular calcification is often present
Mitral regurgitation is variable and often dynamic, depending on the degree of outflow tract obstruction
The LV is usually more involved than the RV
The atria are frequently significantly enlarged
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