Dataset Information

Evaluation of left ventricular outflow tract gradient during treadmill exercise and in recovery period in orthostatic position, in patients with hypertrophic cardiomyopathy.

ABSTRACT:

Background

Left ventricular outflow tract obstruction is an independent predictor of adverse outcome in hypertrophic cardiomyopathy (HCM). The classical quantification of intraventricular obstruction is performed in resting conditions in supine position, but this assessment does not reflect what happens in HCM patients (pts) in their daily activities, neither during effort nor during orthostatic recovery.

Aim

To assess intraventricular gradients with echocardiography during treadmill exercise and in the recovery period in upright position, in HCM pts.

Methods

We studied 17 HCM pts (9 males, mean age 53 +/- 16 years, 11 with obstructive HCM). Each pt had 2 echocardiographic evaluations at rest (left lateral decubitus (LLD) and orthostatic position). The pts then underwent a treadmill exercise test and intraventricular gradients were measured at peak exercise and during recovery in orthostatic position.

Results

3 pts with non-obstructive HCM at rest developed intraventricular gradients during exercise. 1 pt developed this gradient only during orthostatic recovery. The mean intraventricular gradient in LLD was 49 +/- 24 mmHg; in orthostatic position was 62 +/- 29 mmHg (p < 0.001 versus in LLD); at peak exercise was 83 +/- 35 mmHg (p < 0.001 versus supine rest); during recovery it was 96 +/- 35 mmHg (p < 0.001 versus peak exercise)

Conclusion

In HCM pts the intraventricular gradient increases in orthostatic position, increases significantly during treadmill exercise and continues increasing in the recovery period in orthostatic position. This type of evaluation can help us to better understand the physiopathology, the symptoms and the efficacy of different therapeutic modalities in this disease and should be routinely used in the assessment of HCM pts.

SUBMITTER: Miranda R

PROVIDER: S-EPMC2413212 | biostudies-literature | 2008 May

REPOSITORIES: biostudies-literature

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Publications

Evaluation of left ventricular outflow tract gradient during treadmill exercise and in recovery period in orthostatic position, in patients with hypertrophic cardiomyopathy.

Miranda Rita R Cotrim Carlos C Cotrim Carlos C Cardim Nuno N Almeida Sofia S Lopes Luís L Loureiro Maria José MJ Simões Otília O Cordeiro Pedro P Fazendas Paula P João Isabel I Carrageta Manuel M

Cardiovascular ultrasound 20080515

<h4>Background</h4>Left ventricular outflow tract obstruction is an independent predictor of adverse outcome in hypertrophic cardiomyopathy (HCM). The classical quantification of intraventricular obstruction is performed in resting conditions in supine position, but this assessment does not reflect what happens in HCM patients (pts) in their daily activities, neither during effort nor during orthostatic recovery.<h4>Aim</h4>To assess intraventricular gradients with echocardiography during treadm ...[more]

PMID: 18482456

Similar Datasets

Project description:Hypertrophic cardiomyopathy (HCM) is an inherited disease of the heart muscle characterized by otherwise unexplained thickening of the left ventricle. Left ventricular outflow tract (LVOT) obstruction is present in approximately two-thirds of patients and substantially increases the risk of disease complications. Invasive treatment with septal myectomy or alcohol septal ablation can improve symptoms and functional status, but currently available drugs for reducing obstruction have pleiotropic effects and variable therapeutic responses. New medical treatments with more targeted pharmacology are needed, but the lack of preclinical animal models for HCM with LVOT obstruction has limited their development. HCM is a common cause of heart failure in cats, and a subset exhibit systolic anterior motion of the mitral valve leading to LVOT obstruction. MYK-461 is a recently-described, mechanistically novel small molecule that acts at the sarcomere to specifically inhibit contractility that has been proposed as a treatment for HCM. Here, we use MYK-461 to test whether direct reduction in contractility is sufficient to relieve LVOT obstruction in feline HCM. We evaluated mixed-breed cats in a research colony derived from a Maine Coon/mixed-breed founder with naturally-occurring HCM. By echocardiography, we identified five cats that developed systolic anterior motion of the mitral valve and LVOT obstruction both at rest and under anesthesia when provoked with an adrenergic agonist. An IV MYK-461 infusion and echocardiography protocol was developed to serially assess contractility and LVOT gradient at multiple MYK-461 concentrations. Treatment with MYK-461 reduced contractility, eliminated systolic anterior motion of the mitral valve and relieved LVOT pressure gradients in an exposure-dependent manner. Our findings provide proof of principle that acute reduction in contractility with MYK-461 is sufficient to relieve LVOT obstruction. Further, these studies suggest that feline HCM will be a valuable translational model for the study of disease pathology, particularly LVOT obstruction.

Project description:BackgroundData on the outcomes of hypertrophic cardiomyopathy (HCM) with biventricular obstruction are limited.ObjectiveOur aim is to compare mid-term outcomes of biventricular outflow tract obstruction (BVOTO) HCM, left ventricular outflow tract obstruction (LVOTO) HCM and nonobstructive hypertrophic cardiomyopathy (NO-HCM) in children and adolescents who were treated with standard medication or surgical resection.MethodsThis retrospective study identified 21 BVOTO patients and recruited 27 LVOTO and 24 NO-HCM patients younger than 18 years presenting at our institution. The primary endpoint was all-cause death, and secondary endpoints were cardiovascular events.ResultsMore BVOTO patients (61.9%) than LVOTO (19.2%) and NO-HCM patients (25%) exhibited New York Heart Association (NYHA) III/IV status (p < 0.01). Fourteen BVOTO and 16 LVOTO patients obtained a significant reduction of outflow tract pressure gradients after surgery (vs. preoperative baseline, p < 0.001). One of the 14 BVOTO patients died, whereas no deaths occurred among LVOTO patients. Three of 14 BVOTO surgery patients had complete heart block (CHB) and 4 had new right bundle branch block (RBBB), while no CHB or RBBB occurred in the LVOTO surgery patients. The BVOTO patients had a longer duration of aortic cross-clamping and postoperative hospital days than the LVOTO patients (p < 0.05). During a median 42-month follow-up, no deaths occurred among the remaining patients. The primary and secondary endpoint-free survival rates of the BVOTO group were comparable to those of the LVOTO and NO-HCM groups.ConclusionsIn children and adolescents, BVOTO patients were associated with more severe symptoms than LVOTO and NO-HCM patients; however, good mid-term outcomes similar to those of the LVOTO and NO-HCM groups can be achieved with the application of contemporary cardiovascular treatment strategies. Notably, BVOTO surgery was associated with an increased risk of CHB and RBBB compared to LVOTO surgery.

Dataset Information

Evaluation of left ventricular outflow tract gradient during treadmill exercise and in recovery period in orthostatic position, in patients with hypertrophic cardiomyopathy.

Background

Aim

Methods

Results

Conclusion

Publications

Evaluation of left ventricular outflow tract gradient during treadmill exercise and in recovery period in orthostatic position, in patients with hypertrophic cardiomyopathy.

Similar Datasets

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