Hypertrophic cardiomyopathy in special clinical scenarios

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [mailto:mgibson@perfuse.org];

Management of HCM in presence of hypotension and cardiovascular collapse
The first patient I (C. Michael Gibson, M.D.) treated as a medical student was an 18 year old woman who had HOCM. She had just entered college and had partied throughout the night. She was vomiting, developed new atrial fibrillation at a rate of 180 beats per minute. She had a syncopal episode and had a systolic blood pressure of 60 mm Hg. This young lady had sustained hemodynamic collapse as a result of volume depletion and tachycardia.

Precipitants of Hemodynamic Collapse

 * Volume depletion or dehydration which can be due to:
 * Vomiting
 * Diuretics
 * Hemorrhage


 * Reduced pre-load which can be due to:
 * Sepsis
 * Venodilators such as nitrates
 * Following epidural blockade


 * Tachycardia
 * Withdrawal of beta-blockers or calcium channel blockers
 * Decreased afterload due to:
 * Vasodilator therapy
 * Sepsis

Physical examination Findings in Hemodynamic Collapse
A rapid, weak pulse is present in the patient who is hypotensive. The JVP is flat. A systolic murmur is present.

Echocardiographic Findings in Hemodynamic Collapse

 * A small hypercontractile left ventricle is present


 * Prolonged systolic anterior motion of the mitral valve is present


 * Mitral regurgitation with a posterior directed jet

Treatment of Hemodynamic Collapse
Initial treatment includes the following:
 * Avoid nitrates even though it appears the patient is in heart failure!
 * Avoid vasodilators again even though it appears the patient is in heart failure! Both these agents could cause further hemodynamic compromise.
 * Administer beta-blockers to slow the heart rate and fluids to raise the left ventricular filling pressures.
 * Elevate the legs to increase venous return and raise the preload

If the patient does not respond to these measures, then the following can also be administered:
 * Intravenous phenylephrine at a rate of 100 to 180 µg/min, which is then reduced to 2 to 3 mL/min (40 to 60 drops/min).
 * How to mix the phenylephrine: Make a solution that contains 10 mg (1 mL of 1 percent phenylephrine) of phenylephrine diluted in 500 mL of D5W. Administer at a rate of 5 to 9 mL/min (i.e. 100 to 180 drops/min assuming there are 20 drops/mL). This solution provides a phenylephrine drip of 100 to 180 µg/min.


 * Outside of the US, intravenous disopyramide at a dose of 50 mg over one to five minutes can be administered.

2011 ACCF/AHA Guideline Recommendations: Asymptomatic Patients
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Class I
1. For patients with HCM, it is recommended that comorbidities that may contribute to cardiovascular disease (e.g., hypertension, diabetes, hyperlipidemia, obesity) be treated in compliance with relevant existing guidelines. (Level of Evidence: C)

Class IIa
1. Low-intensity aerobic exercise is reasonable as part of a healthy lifestyle for patients with HCM. (Level of Evidence: C)

Class IIb
1. The usefulness of beta blockade and calcium channel blockers to alter clinical outcome is not well established for the management of asymptomatic patients with HCM with or without obstruction. (Level of Evidence: C)

Class III (Harm)
1. Septal reduction therapy should not be performed for asymptomatic adult and pediatric patients with HCM with normal effort tolerance regardless of the severity of obstruction. (Level of Evidence: C)

2. In patients with HCM with resting or provocable outﬂow tract obstruction, regardless of symptom status, pure vasodilators and high-dose diuretics are potentially harmful. (Level of Evidence: C)}}

2011 ACCF/AHA Guideline Recommendations: Patients With LV Systolic Dysfunction
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Class I
1. Patients with non-obstructive HCM who develop systolic dysfunction with an EF less than or equal to 50% should be treated according to evidence-based medical therapy for adults with other forms of heart failure with reduced EF, including angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, beta blockers, and other indicated drugs.(39,378) (Level of Evidence: B)

2. Other concomitant causes of systolic dysfunction (such as CAD) should be considered as potential contributors to systolic dysfunction in patients with HCM. (Level of Evidence: C)

Class IIb
1. ICD therapy may be considered in adult patients with advanced (as deﬁned by NYHA functional class III or IV heart failure) non-obstructive HCM, on maximal medical therapy, and EF less than or equal to 50%, who do not otherwise have an indication for an ICD.(39) (Level of Evidence: C)

2. For patients with HCM who develop systolic dysfunction, it may be reasonable to reassess the use of negative inotropic agents previously indicated, for example, verapamil, diltiazem, or disopyramide, and to consider discontinuing those therapies.(Level of Evidence: C)}}

Guideline Resources
2011 ACCF/AHA Guideline for the Diagnosis and Treatment of Hypertrophic Cardiomyopathy