Pocket Medicine: The Massachusetts General Hospital Handbook of Internal Medicine (12 page)

mitral leaflets and papillary muscles (pansystolic, ant.-directed regurg. jet)

• Diastolic dysfunction: ↑ chamber stiffness + impaired relaxation

• Ischemia: small vessel dis., perforating artery compression (bridging), ↓ coronary perfusion • Syncope: Δs in load-dependent CO, arrhythmias

Clinical manifestations (70% are asymptomatic at dx)

•
Dyspnea
(90%): due to ↑ LVEDP, MR, and diastolic dysfunction •
Angina
(25%) even w/o epicardial CAD; microvasc. dysfxn (
NEJM
2003;349:1027) •
Arrhythmias
(AF in 20–25%; VT/VF) → palpitations, syncope, sudden cardiac death
Physical exam

• Sustained PMI, S
₂
paradoxically split if severe outflow obstruction,
S
₄
(occ. palpable) •
Systolic murmur
: crescendo-decrescendo; LLSB; ↑
w/ Valsalva
& standing (↓ preload) • ± mid-to-late or holosystolic murmur of MR at apex

• Bifid carotid pulse (brisk rise, decline, then 2nd rise); JVP w/ prominent
a
wave • Contrast to AS, which has murmur that ↓ w/ Valsalva and ↓ carotid pulses
Diagnostic studies

• CXR: cardiomegaly (LV and LA)

• ECG: LVH, anterolateral and inferior pseudo-Qw, ± apical giant TWI (apical variant) •
Echo
: no absolute cutoffs for degree of LVH but septum/post. wall ≥1.3 suggestive,

as is septum >15 mm; other findings include dynamic outflow obstruction, SAM, MR

• MRI: hypertrophy + patchy delayed enhancement (useful for dx & prog) ( 
JACC CV Imag
2012;2:370) • Cardiac cath: subaortic pressure ∇;
Brockenbrough sign
= ↓ pulse pressure post-PVC (in contrast to AS, in which pulse pressure ↑ post-PVC) • ? Genotyping for family screening, but pathogenic mutation ID’d in <½ (
Circ
2011;124:2761)
Treatment (
Circ
2011;124:e783 & 2012;125:1432;
Lancet
2013;381:242)

• Heart failure

inotropes/chronotropes
: b-blockers, CCB (verapamil), disopyramide

Careful use of diuretics, as may further ↓ preload. Vasodilators only if systolic dysfxn. Avoid digoxin.

If sx refractory to drug Rx +
obstructive
physiology (∇ >50 mmHg):

(a) Surgical myectomy: long-term ↓ symptoms in 90% (
Circ
2005;112:482)

(b) Alcohol septal ablation (
Circ
CV Interv
2011;4;256;
JACC
2011;58:2322): gradient ↓ by ~80%, only 5–20% remain w/ NYHA III–IV sx; 14% require repeat ablation or myectomy. Good alternative for older Pts, multiple comorbidities. Complic: transient (& occ. delayed) 3° AVB w/ 10–20% req. PPM; VT due to scar formation.

No clear benefit of dual-chamber pacing ( 
JACC
1997;29:435;
Circ
1999;99:2927)

If refractory to drug therapy and there is
nonobstructive
pathophysiology: transplant

• Acute HF: can be precip. by dehydration or tachycardia; Rx w/ fluids, bB, phenylephrine • AF: rate control with bB, maintain SR with disopyramide, amiodarone

• SCD: ICD ( 
JACC
2003;42:1687). Risk factors: h/o VT/VF,
FHx SCD, unexplained syncope, NSVT, ↓ SBP or rel HoTN (↑ SBP <20 mmHg) w/ exercise, LV wall ≥30 mm, extensive MRI delayed enhancement. EPS
not
useful. Risk 4%/y if high-risk (
JAMA
2007;298:405).

• Counsel to avoid dehydration, extreme exertion

• Endocarditis prophylaxis not recommended (
Circ
2007;16:1736) • First-degree relatives: periodic screening w/ echo, ECG (as timing of HCMP onset variable). Genetic testing if known mutation.

RESTRICTIVE CARDIOMYOPATHY (RCMP)

Definition (
Circ
2006;113:1807)

• Impaired ventricular filling with ↓ complicance in nonhypertrophied, nondilated ventricles; normal or ↓ diastolic volumes, normal or near-normal EF; must r/o pericardial disease
Etiology ( 
JACC
2010;55:1769)

•
Myocardial processes

Autoimmune (scleroderma, polymyositis-dermatomyositis)

Infiltrative diseases (see primary entries for extracardiac manifestations, Dx, Rx)

Amyloidosis
(
CIrc
2011;124:1079): age at presentation ~60 y;
:
= 3:2 AL (MM, light-chain, MGUS, WM); familial (transthyretin, TTR); AA/senile (TTR, ANP) ECG: ↓ QRS amplitude (50%), pseudoinfarction pattern (Qw), AVB (10–20%),  hemiblock (20%), BBB (5–20%)

Echo: biventricular wall thickening (
yet w/ low voltage on ECG
), granular sparkling texture (30%), biatrial enlargement (40%), thickened atrial septum, valve thickening (65%), diastolic dysfxn, small effusions

Normal voltage & normal septal thickness has NPV ~90%

MRI: distinct late gadolinium enhancement pattern ( 
JACC
2008;51:1022)

Sarcoidosis
: age at present. ~30 y; more common in blacks, N. Europeans, women

5% of those w/ sarcoid have overt cardiac involvement; cardiac w/o systemic in 10%

ECG: AVB (75%), RBBB (20–60%), VT; PET: ↑ FDG uptake in affected area

Echo: regional WMA (particularly basal septum) with thinning or mild hypertrophy

Nuclear imaging: gallium uptake in areas of sestaMIBI perfusion defects; cardiac MR

Hemochromatosis
: in middle-aged men (esp. N. European); 15% p/w cardiac sx

Storage diseases: Gaucher’s, Fabry, Hurler’s, glycogen storage diseases

Diabetes mellitus

•
Endomyocardial processes

Chronic eosinophilic: Löffler’s endocarditis (temperate climates; ↑ eos; mural thrombi that embolize); endomyocardial fibrosis (tropical climates; var. eos; mural thrombi)

Toxins: radiation (also p/w constrictive pericarditis, valvular dis, ostial CAD), anthracyclines

Serotonin: carcinoid, serotonin agonists, ergot alkaloids

Metastatic cancer

Pathology & pathophysiology

• Path: normal or ↑ wall thickness ± infiltration or abnormal deposition • ↓ myocardial compliance → nl EDV but ↑ EDP → ↑ systemic & pulm. venous pressures • ↓ ventricular cavity size → ↓ SV and ↓ CO

Clinical manifestations (
Circ
2000;101:2490)

•
Right-sided
>
left-sided heart failure
with peripheral edema > pulmonary edema •
Diuretic “refractoriness”

•
Thromboembolic events
• Poorly tolerated tachyarrhythmias; VT → syncope/sudden cardiac death
Physical exam

• ↑ JVP, ± Kussmaul’s sign ( JVP ↑ w/ inspiration, classically seen in
constrictive pericarditis
) • Cardiac: ± S
₃
and S
₄
, ± murmurs of MR and TR