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Changes in left ventricular filling and left atrial function six months after nonsurgical septal reduction therapy
S F Nagueh1, N M Lakkis, K J Middleton
1Department of Medicine, Baylor College of Medicine, Houston, Texas 77030, USA. sherifn@bcm.tmc.edu
Insights
Nonsurgical septal reduction therapy (NSRT) improves left ventricular (LV) filling and reduces left atrial (LA) size and function in patients with hypertrophic obstructive cardiomyopathy (HOCM). This treatment enhances exercise capacity and reduces obstruction, offering significant benefits for HOCM patients.
Area of Science:
- Cardiology
- Cardiac Imaging
- Interventional Cardiology
Background:
- Hypertrophic obstructive cardiomyopathy (HOCM) is often associated with enlarged left atria (LA), increasing atrial fibrillation risk.
- Nonsurgical septal reduction therapy (NSRT) effectively reduces left ventricular outflow tract (LVOT) obstruction and improves symptoms in HOCM.
- The impact of NSRT on left ventricular (LV) passive filling, LA volumes, and function remains incompletely understood.
Purpose of the Study:
- To evaluate changes in LV filling, LA volumes, and LA function six months post-NSRT in HOCM patients.
- To assess the noninvasive hemodynamic and functional effects of NSRT on the left heart.
Main Methods:
- Thirty HOCM patients underwent comprehensive echocardiography and treadmill exercise testing before and six months after NSRT.
- Key parameters assessed included LVOT gradient, mitral regurgitant (MR) volume, LV filling pressures, and LA volumes.
- LA ejection force and kinetic energy (KE) were calculated noninvasively and compared to healthy controls.
Main Results:
- NSRT significantly improved New York Heart Association (NYHA) class and exercise duration (p < 0.05).
- LVOT gradient, MR volume, and LV filling pressures were substantially reduced post-NSRT.
- LV passive filling volume increased significantly (p < 0.01), while LA volumes, ejection force, and KE decreased (p < 0.01).
Conclusions:
- Nonsurgical septal reduction therapy effectively increases LV passive filling volume in HOCM patients.
- NSRT leads to a significant reduction in LA size, ejection force, and kinetic energy.
- These findings highlight NSRT's positive impact on LV diastolic function and LA remodeling.
Objectives:
The purpose of this study was to evaluate changes in left ventricular (LV) filling, left atrial (LA) volumes and function six months after nonsurgical septal reduction therapy (NSRT) for hypertrophic obstructive cardiomyopathy (HOCM).
Background:
Patients with HOCM frequently have enlarged left atria, which predisposes them to atrial fibrillation. Nonsurgical septal reduction therapy results in significant reduction in left ventricular outflow tract (LVOT) obstruction and symptomatic improvement. However, its effect on LV passive filling volume, LA volumes and function is not yet known.
Methods:
Thirty patients with HOCM underwent treadmill exercise testing as well as 2-dimensional and Doppler echocardiography before and six months after NSRT. Data included clinical status, exercise duration, LVOT gradient, mitral regurgitant (MR) volume, LV pre-A pressure and LA volumes. Left atrial ejection force and kinetic energy (KE) were computed noninvasively and were compared with 12 age-matched, normal subjects.
Results:
New York Heart Association (NYHA) class was lower and exercise duration was longer (p < 0.05) six months after NSRT. The LVOT gradient, MR volume and LV pre-A pressure were all significantly reduced. HOCM patients had larger atria, which had a higher ejection force and KE, compared with normal subjects (p < 0.01). After NSRT, LV passive filling volume increased (p < 0.01), whereas LA volumes, ejection force and KE decreased (p < 0.01). Reduction in LA maximal volume was positively related to changes in LV pre-A pressure (r = 0.8, p < 0.05) and MR volume (0.4, p < 0.05). Changes in LA ejection force were positively related to changes in LA pre-A volume (r = 0.7, p < 0.01) and KE (r = 0.81, p < 0.01). The increase in exercise duration paralleled the increase in LV passive filling volume (r = 0.85, p < 0.05).
Conclusions:
Nonsurgical septal reduction therapy results in an increase in LV passive filling volume and a reduction in LA size, ejection force and KE.