Hypertrophic cardiomyopathy ventricular pacing

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [mailto:mgibson@perfuse.org]; Cafer Zorkun, M.D. [mailto:zorkun@perfuse.org]; Caitlin J. Harrigan [mailto:charrigan@perfuse.org]; Martin S. Maron, M.D.; Barry J. Maron, M.D.;

Overview
The use of a pacemaker has been advocated in a subset of individuals, in order to cause asynchronous contraction of the left ventricle. Since the pacemaker activates the interventricular septum before the left ventricular free wall, the gradient across the left ventricular outflow tract may decrease. The AV interval must be shortened to do this, but not at the expense of diastolic filling. This form of treatment has been shown to provide less relief of symptoms and less of a reduction in the left ventricular outflow tract gradient when compared to surgical myectomy . Dual chamber pacing does not decrease the risk of sudden cardiac death in these patients.

==2011 ACCF/AHA Guideline Recommendations: Pacing ==

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Class IIa
1. In patients with HCM who have had a dual-chamber device implanted for non-HCM indications, it is reasonable to consider a trial of dual-chamber atrial-ventricular pacing (from the right ventricular apex) for the relief of symptoms attributable to LVOT obstruction.(292,294,295,366) (Level of Evidence: B)

Class IIb
1. Permanent pacing may be considered in medically refractory symptomatic patients with obstructive HCM who are suboptimal candidates for septal reduction therapy.(283,292,294,295,366) (Level of Evidence: B)

Class III (No Benefit)
1. Permanent pacemaker implantation for the purpose of reducing gradient should not be performed in patients with HCM who are asymptomatic or whose symptoms are medically controlled.(283,284,367) (Level of Evidence: C)

2. Permanent pacemaker implantation should not be performed as a ﬁrst-line therapy to relieve symptoms in medically refractory symptomatic patients with HCM and LVOT obstruction who are candidates for septal reduction.(283,284,367) (Level of Evidence: B)}}

==2007 ESC Guidelines- Cardiac Pacing in HCM ==

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Class IIa
1. Symptomatic bradycardia due to beta-blockade when alternative therapies are unacceptable. (Level of Evidence: C)

Class IIb
1. Patients with drug refractory hypertrophic cardiomyopathy with signiﬁcant resting or provoked LVOT gradient  and contraindications for septal ablation or myectomy. (Level of Evidence: A)

Class III
1. Asymptomatic patients. (Level of Evidence: C)

2. Symptomatic patients who do not have LVOT obstruction. (Level of Evidence: C)}}

Guideline Resources

 * ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities


 * The Task Force for Cardiac Pacing and Cardiac Resynchronization Therapy of the European Society of Cardiology. Developed in Collaboration with the European Heart Rhythm Association


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