Ver el código de «Hypertrophic cardiomyopathy»

==Background==
[[File:Hypertrophic_cardiomyopathy.png|thumb|HOCM]]
*Genetically-linked (AD) hypertrophy of cardiac muscle - can but does not always cause outflow obstruction
*Up to 30% of patients will have no family history<ref>Gersh BJ, Maron BJ, Bonow RO, Dearani JA, Fifer MA, Link MS, Naidu SS, Nishimura RA, Ommen SR, Rakowski H, Seidman CE, Towbin JA, Udelson JE, Yancy CW. 2011 ACCF/AHA Guideline for the Diagnosis and Treatment of Hypertrophic Cardiomyopathy: Executive Summary. A report of the American College of Cardiology Foundation/American Heart Association Task Force of Practice.</ref>
*Average age of diagnosis between 30-40 years of age
*Diastolic [[heart failure]]
**Abnormal LV function due to decreased compliance
*Historically, obstructive forms known as:
**Idiopathic hypertrophic subaortic stenosis (IHSS)
**Asymmetric septal hypertrophy (ASH)
**Hypertrophic obstructive cardiomyopathy (HOCM)
*Yamaguchi syndrome, an atypical HCOM, in which only 1% are non-Japanese

{{Cardiomyopathy DDX}}

==Clinical Features==
===History===
*[[Syncope]], [[chest pain]], [[dyspnea]], dizziness
*Symptoms made worse by exertion
**Increasing ventricular contractility further narrows outflow as volume is lost

===Physical===
*Harsh midsystolic crescendo-decrescendo [[murmur]]
**Increases in intensity with valsalva and standing up
***Due to decreased blood return to the heart
**Decreases with squatting and Trendelenburg
***Due to increased peripheral resistance increases aorta and reduces obstruction

==Differential Diagnosis==
{{DDX syncope peds}}
{{Chest Pain DDX}}

==Evaluation==
[[File:Needle-like q-waves.JPG|thumbnail|Needle-like Q-waves]]
[[File:HOCM Subramaniam.gif|thumbnail|HOCM<ref>http://www.thepocusatlas.com/pediatrics/</ref>]]

===Work-Up===
*[[ECG]] abnormalities in ~90%, but mostly nonspecific
**High voltage ECG (which may produce abnormal T-waves)
**[[LVH]]
**[[Left atrial enlargement]]
**Tall R-wave in V1, mimicking posterior MI
**"Needle-like" Q waves, especially in lateral leads, mimicking infarction Q waves
*[[CXR]] may be normal as LV is non-dilated
*Echo<ref>Mitevksa IP. Focus on echocardiography in hypertrophic cardiomyopathy - fourth in series. ESC Council for Cardiology Practice. Vol.13,N°20 - 14 Apr 2015.</ref>
**Unexplained wall thickness > 15 mm in any myocardial segment
**Septal/posterior wall thickness ratio:
***>1.3 in normotensive pts
***>1.5 in hypertensive pts
**Systolic anterior motion by M mode in PSL window, worsened by Valsalva
**[[Mitral regurgitation]]
**EF may be preserved until acute decompensation
**Formal echo should include tissue Doppler imaging

===Diagnosis===
*Typically via echo

==Management==
*Avoid exertion
*ICD +/- pacer for [[ventricular dysrhythmias]]
*Definitive treatment is myomectomy

===Decompensated===
*Consider primary insult, which usually is preload issue (fluid depletion, bleed, etc.)
*If decompensated presents as [[cardiogenic shock|hypotensive CHF]]
**Preserve preload
***Careful hydration
***Avoid high airway pressure if intubate
**Limit tachycardia
***[[Beta blockers]]
**Avoid vasodilators (''no'' nitrates)
**Maintain sinus rhythm (i.e. cardiovert A. fib)
**Increase afterload (hypotensive only)
***[[Phenylephrine]], max dose range depending on source
****Start at 100 mcg/min (~1.5 mcg/kg/min for average adult)
****Range usually 0.5 - 6.0 mcg/kg/min, with efficacy minimal beyond 6 mcg/kg/min)<ref>Global RPH in reference to Micromedex. 12/2014. http://www.globalrph.com/phenylephrine_dilution.htm</ref>
****Max phenylephrine infusion before other pressors
****Fix acid-base disorder as acidosis may prevent pressor efficacy
****Consider maxing [[vasopressin]] next
*****Pressor effects more preserved in hypoxia and acidosis<ref>Overgaard CB and Dzavik V. Contemporary Reviews in Cardiovascular Medicine: Inotropes and Vasopressors - Review of Physiology and Clinical Use in Cardiovascular Disease. Circulation. 2008; 118: 1047-1056.</ref>
*****Preferred over pressors with beta agonism
***Push dose pressor while waiting for IV drip:
****Place 1mL of 10mg/mL phenylephrine in 100mL NS
****Final concentration 100mcg/mL
****Use 1-2mL q2-5min (100-200mcg) in 10mL syringe
****Onset 1min; duration 20min

===Pharmacologic Management===
*Per Amer Coll of Cardiology 2011 recommendations<ref>American College of Cardiology. 2011. http://content.onlinejacc.org/article.aspx?articleid=1147838</ref>
*Class I
**[[beta-blockers]] for angina or dyspnea in adults in HCM regardless of obstructive physiology - use with caution in sinus brady or conduction abnormality
**Titrate BB dose to symptoms, may increase BB dose to resting HR to 60 bpm
**[[Verapamil]] PO titrated up to 480mg/d if patient unresponsive or cannot tolerate beta-blockers - caution in advanced HF, hypotension, sinus brady, high LVOT gradients
**'''IV [[phenylephrine]]''' for acute hypotension unresponsive to fluids
*Class IIa
**Reasonable to add disopyramide with BB or verapamil if unresponsive to BB or CCB alone in obstructive HCM
**Reasonable to add oral [[diuretics]] in nonobstructive HCM when symptoms persist despite BB or CCB
*Class III (harm)
**''Avoid'' [[nifedipine]] and other dihydropyridine CCB
**''Avoid'' [[digoxin]]
**''Avoid'' disopyramide alone with out BB or CCB
**'''Avoid positive inotropic vasopressors''' (dopamine, dobutamine, norepinephrine, epi)

==Disposition==
*Admit for echo and cardiology evaluation
*If unable to admit, home on β-blocker, instructions for no exertion, follow up echo and cardiology outpatient

==See Also==
*[[Cardiomyopathy]]
*[https://www.youtube.com/watch?v=RsNkhr4lhhU Amal Mattu July 30, 2012 case]

==References==
<references/>

[[Category:Cardiology]]