Permanent Pacing for Drug-refractory Symptomatic Patients With Obstructive Hypertrophic Cardiomyopathy.

Study Overview
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Brief Summary
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The present trial is undertaken as a pilot study on selected patients, to evaluate the ability of acute hemodynamic testing to optimize pacing therapy and to predict the response of Obstructive Hypertrophic Cardiomyopathy (OHCM) to pacing, in terms of reduction of Left Ventricular Outflow Tract (LVOT) pressure gradient and functional capacity improvement. The Primary Objective is to demonstrate a long-term reduction in LVOT obstruction at rest and/or after Valsalva/Exercise > 30% in patients responding to acute stimulation test

Official Title
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Permanent Pacing as a Treatment for Drug-refractory Symptomatic Patients With Obstructive Hypertrophic Cardiomyopathy.

Conditions
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Obstructive Hypertrophic Cardiomyopathy

Intervention / Treatment
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* Procedure: pace maker implant guided by acute hemodynamic testing


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: unequivocal diagnosis of HCM, on the basis of 2-dimensional echocardiographic demonstration of a hypertrophied (wall thickness >15 mm or > 13 mm in familial HOCM) and non dilated LV in the absence of another cardiac or systemic disease capable of producing the same magnitude of hypertrophy; patients in whom coronary disease has been excluded; presence of severe refractory symptoms (NYHA class II-IV), as evidenced by moderate-to-severe functional disability resulting from exertional dyspnea or chest pain sufficient to support a desire for alternative treatment modalities, following administration (in standard dosages) of beta-blocker and either disopyramide or verapamil, independently or in association; peak instantaneous LV outflow tract gradient > 50 mm Hg (resting or provoked), estimated by continuous wave Doppler; Exclusion Criteria: end-stage phase of HCM (unless CRT therapy is considered); ejection fraction <50% (unless CRT therapy is considered); severe mitral valve disease (+++) not related to systolic anterior movement and/or papillary muscle abnormalities; age below 18 years.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: HCM patients with LVOT obstruction<br>Patients with obstructive HCM are considered for this study if 1) symptomatic, 2) refractory to optimized medical therapy and 3) not or poorly* eligible for septal myectomy or with an indication to implant a pacing device (pacemaker or ICD) independent on the ventricular obstruction. | Procedure: pace maker implant guided by acute hemodynamic testing<br>* To evaluate the ability of acute hemodynamic testing to optimize pacing therapy and to predict the response of HOCM to pacing<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Reduction of LVOT pressure gradient | Long-term reduction in LVOT obstruction at rest and/or after Valsalva/Exercise > 30% in patients responding to acute stimulation test | 3 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Clinical improvement: change in NYHA class | Improvement of NYHA class | 6-12 months | 
| Clinical improvement: change in exercise capacity | 6-minutes walking test | 6-12 months | 
| Clinical improvement: change in peak VO2 | Improvement in peak VO2 | 6-12 months | 
| Clinical improvement: change in NT-proBNP concentration | Reduction in NT-proBNP concentration | 6-12 months |