Signs

 The obstructive form of hypertrophic cardiomyopathy (HOCM) is associated with a midsystolic murmur that is usually loudest along the left sternal border or between the left lower sternal border and the apex. The murmur is produced by both dynamic left ventricular outflow tract obstruction and MR, and thus, its configuration is a hybrid between ejection and regurgitant phenomena. The intensity of the murmur may vary from beat to beat and after provocative maneuvers but usually does not exceed grade 3. The murmur classically will increase in intensity with maneuvers that result in increasing degrees of outflow tract obstruction, such as a reduction in preload or afterload (Valsalva, standing, vasodilators) or with an augmentation of contractility (inotropic stimulation such as milrinone). However, augmentation of contractility will also increase the intensity of the murmur of aortic stenosis and thus is not useful for differentiation. Augmentation of afterload (hand grip) is associated with diminished murmur intensity in both aortic stenosis and obstructive hypertrophic cardiomyopathy. Maneuvers that increase preload (squatting, passive leg raising, volume administration) or afterload (squatting, vasopressors) or agents that reduce contractility (β-adrenoceptor blockers) decrease the intensity of the murmur of hypertrophic cardiomyopathy. In contrast to AS, the carotid upstroke is rapid and of normal volume. Rarely, it is bisferiens or bifid in contour due to midsystolic closure of the aortic valve.

 

 

 

 

 

Hypertrophic cardiomyopathy is characterized by a stiff noncompliant left ventricle, diastolic dysfunction, and outflow tract obstruction.

 

 

 

 

It is the most common cause of sudden cardiac death in young adults, but the disorder may be first recognized in those >60 years old.11

 

Complications of Injecting Drug Use

  • Local problems—Abscess (Figures 240-2 
    Image not available.

    A 32-year-old woman with type 1 diabetes developed large abscesses all over her body secondary to injection of cocaine and heroin. Her back shows the large scars remaining after the healing of these abscesses. (Courtesy of ­Richard P. Usatine, MD.)

    and 240-3; Abscess), cellulitis, septic thrombophlebitis, local induration, necrotizing fasciitis, gas gangrene, pyomyositis, mycotic aneurysm, compartmental syndromes, and foreign bodies (e.g., broken needle parts) in local areas.2
    • IDUs are at higher risk of getting methicillin-resistant Staphylococcus aureus(MRSA) skin infections that the patient may think are spider bites (Figure 240-4).
    • Some IDUs give up trying to inject into their veins and put the cocaine directly into the skin. This causes local skin necrosis that produces round atrophic scars (Figure 240-5).
  • IDUs are at risk for contracting systemic infections, including HIV and hepatitis B or hepatitis C.
    • Injecting drug users are at risk of endocarditis, osteomyelitis (Figures 240-6and 240-7), and an abscess of the epidural region. These infections can lead to long hospitalizations for intravenous antibiotics. The endocarditis that occurs in IDUs involves the right-sided heart valves (see Chapter 50, Bacterial Endocarditis).2 They are also at risk of septic emboli to the lungs, group A β-hemolytic streptococcal septicemia, septic arthritis, and candidal and other fungal infections.

 

Content 3

Content 13

Content 11

Mr. Abraham is a 62-year-old former sea urchin collector with a history of right total knee replacement 10 years ago and prior tobacco abuse. He presents to your office complaining of chest pain with moderate exertion and some mild dyspnea with walking up hills. On examination, you note a mid-systolic murmur. After careful listening, you are unsure whether this is the murmur of aortic stenosis or of the obstructive form of hypertrophic cardiomyopathy. Which maneuver is appropriately matched to the clinical finding that would suggest that this murmur is due to obstructive hypertrophic cardiomyopathy as opposed to aortic valvular stenosis?

The answer is E.  The obstructive form of hypertrophic cardiomyopathy (HOCM) is associated with a midsystolic murmur that is usually loudest along the left sternal border or between the left lower sternal border and the apex. The murmur is produced by both dynamic left ventricular outflow tract obstruction and MR, and thus, its configuration is a hybrid between ejection and regurgitant phenomena. The intensity of the murmur may vary from beat to beat and after provocative maneuvers but usually does not exceed grade 3. The murmur classically will increase in intensity with maneuvers that result in increasing degrees of outflow tract obstruction, such as a reduction in preload or afterload (Valsalva, standing, vasodilators) or with an augmentation of contractility (inotropic stimulation such as milrinone). However, augmentation of contractility will also increase the intensity of the murmur of aortic stenosis and thus is not useful for differentiation. Augmentation of afterload (hand grip) is associated with diminished murmur intensity in both aortic stenosis and obstructive hypertrophic cardiomyopathy. Maneuvers that increase preload (squatting, passive leg raising, volume administration) or afterload (squatting, vasopressors) or agents that reduce contractility (β-adrenoceptor blockers) decrease the intensity of the murmur of hypertrophic cardiomyopathy. In contrast to AS, the carotid upstroke is rapid and of normal volume. Rarely, it is bisferiens or bifid in contour due to midsystolic closure of the aortic valve.

 

A 22-year-old high school athlete presents to your clinic after passing out during a football game. He is in excellent health, however notes that his athletic older brother died suddenly when he was 23 years old. Sudden deaths are reported to have occurred in other close family members as well. An ECG is done in clinic and is normal. On examination, a crescendo-decrescendo murmur is heard along the left sternal border, which increases with a Valsalva maneuver, and does not radiate to the carotid arteries. What test will provide further evidence to make your diagnosis?

The correct answer is B.

The patient has a history suggestive of hypertrophic cardiomyopathy, and an echocardiogram would help demonstrate structural heart disease, including thickening of the intraventricular septum with resultant dynamic LV outflow obstruction, to support this diagnosis. It is typically inherited in an autosomal dominant fashion with variable penetrance, which is suggested by the family history. The murmur heard on the patient's examination is also consistent, and the decrease in systemic venous return caused by the Valsalva maneuver exacerbates the dynamic outflow obstruction, and its associated murmur.

 

Content 3

 

USMLE Reviewer (Subscription Required)