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Journal of Thoracic Disease Jun 2022The prevalence of hypertrophic cardiomyopathy (HCM) is estimated to be 1 in 200 to 500 individuals, with systolic anterior motion (SAM) of the mitral valve (MV) and left... (Review)
Review
BACKGROUND AND OBJECTIVE
The prevalence of hypertrophic cardiomyopathy (HCM) is estimated to be 1 in 200 to 500 individuals, with systolic anterior motion (SAM) of the mitral valve (MV) and left ventricular outflow tract (LVOT) obstruction present in 60% to 70%. In this narrative review, we aim to elucidate the pathophysiology of SAM-septal contact and LVOT obstruction in HCM by presenting a detailed review on the anatomy of the MV apparatus in HCM, examining the various existing theories pertaining to the SAM phenomenon as supported by cardiac imaging, and providing a critical assessment of management strategies for SAM in HCM.
METHODS
A literature review was performed using PubMed, EMBASE, Ovid, and the Cochrane Library, of all scientific articles published through December 2021. A focus was placed on descriptive studies, reports correlating echocardiographic findings with pathologic diagnosis, and outcomes studies.
KEY CONTENT AND FINDINGS
The pathophysiology of SAM involves the complex interplay between HCM morphology, MV apparatus anatomic abnormalities, and labile hemodynamic derangements. Echocardiography and cardiac magnetic resonance (CMR) vector flow mapping have identified drag forces, as opposed to the "Venturi effect", as the main hydraulic forces responsible for SAM. The degree of mitral regurgitation with SAM is variable, and its severity is correlated with degree of LVOT obstruction and outcomes. First line therapy for the amelioration of SAM and LVOT obstruction is medical therapy with beta-blockers, non-dihydropyridine calcium-channel blockers, and disopyramide, in conjunction with lifestyle modifications. In refractory cases septal reduction therapy is performed, which may be combined with a 'resect-plicate-release' procedure, anterior mitral leaflet extension, surgical edge-to-edge MV repair, anterior mitral leaflet retention plasty, or secondary chordal cutting.
CONCLUSIONS
Recent scientific advances in the field of HCM have allowed for a maturation of our understanding of the SAM phenomenon. Cardiac imaging plays a critical role in its diagnosis, treatment, and surveillance, and in our ability to apply the appropriate therapeutic regimens. The increasing prevalence of HCM places an emphasis on continued basic and clinical research to further improve outcomes for this challenging population.
PubMed: 35813751
DOI: 10.21037/jtd-22-182 -
Expert Review of Cardiovascular Therapy Jan 2023Hypertrophic cardiomyopathy (HCM) is a genetic cardiac disorder leading to hypertrophy of the left ventricle excluding other etiologies. Patients can experience... (Review)
Review
INTRODUCTION
Hypertrophic cardiomyopathy (HCM) is a genetic cardiac disorder leading to hypertrophy of the left ventricle excluding other etiologies. Patients can experience exertional chest pain, dyspnea, syncope or even sudden cardiac death (SCD). Traditional medical management consists of beta blockers (BB), nondihydropyridine calcium channel blockers and disopyramide. Mavacamten, a novel cardiac myosin inhibitor, has recently been shown to improve both quantitative and qualitative measures of obstructive HCM allowing some patients to defer septal reduction therapy.
AREAS COVERED
This review delves into the pharmacotherapy of mavacamten, the evidence behind this first-in-class drug for HCM, guidance for clinical usage, and possible future uses for cardiac myosin inhibitors.
EXPERT OPINION
Mavacamten should be incorporated into the standard armamentarium of medications used to treat obstructive HCM. PIONEER-HCM, EXPLORER-HCM and VALOR-HCM demonstrated improvements in peak LVOT gradient both at rest and post-exercise, cardiac biomarkers, New York Heart Association (NYHA) functional class and Kansas City Cardiomyopathy Questionnaire (KCCQ) scores. Unlike other medications utilized for treatment, mavacamten can delay or even obviate the need for septal reduction therapy.
Topics: Humans; Adult; Cardiomyopathy, Hypertrophic; Heart; Benzylamines; Cardiac Myosins
PubMed: 36522857
DOI: 10.1080/14779072.2023.2159811 -
Journal of Clinical Medicine Apr 2023Although disopyramide has been widely used to reduce left ventricular outflow obstruction (LVOTO) and to improve symptoms in patients with obstructive hypertrophic...
Although disopyramide has been widely used to reduce left ventricular outflow obstruction (LVOTO) and to improve symptoms in patients with obstructive hypertrophic cardiomyopathy (oHCM), its use in real world as well as patient characteristics associated with a positive treatment response are still unclear. From 1980 to 2021, 1527 patients with HCM were evaluated and 372 (23%) had a LVOTO with active follow-up. The efficacy and safety of disopyramide were assessed systematically during 12 months (2-, 6-, and 12-month visits). Responders were patients with a final NYHA = I and a LVOTO < 30 mmHg; incomplete responders were those patients with NYHA > I and a LVOTO < 30 mmHg; and non-responders were symptomatic patients with no change in functional class NYHA and a LVOT gradient > 30 mmHg. Two-hundred-fifty-four (66%) patients were in functional class NYHA I/II and 118 (34%) in NYHA III/IV. A total of 118/372 (32%, 55 ± 16 years) underwent disopyramide therapy. Twenty-eight (24%) patients responded to therapy, 39 (33%) were incomplete responders, and 51 (43%) did not respond. Responder were mainly patients in functional NYHA class I/II (24/28, 86%), whereas incomplete responders and non-responders were more often in functional NYHA class III/IV (50/54 (93%)). An independent predictor of response to disopyramide treatment was the presence of NYHA I/II at the initiation of therapy (HR 1.5 (95% CI 1.1-4.5), = 0.03). No major life-threatening arrhythmic events or syncope occurred, despite 19 (16%) patients showing reduced QTc from baseline, 19 (16%) having no difference, while 80 (69%) patients had prolonged QTc interval. Thirty-one (26%) patients experienced side effects, in particular, 29 of the anticholinergic type. Disopyramide was underused in oHCM but effective in reducing LVOTO gradients and symptoms in slightly symptomatic patients with less severe disease phenotype with a safe pro-arrhythmic profile.
PubMed: 37048808
DOI: 10.3390/jcm12072725 -
The Annals of Pharmacotherapy Apr 2023To assess mavacamten's role in hypertrophic cardiomyopathy treatment. (Review)
Review
OBJECTIVE
To assess mavacamten's role in hypertrophic cardiomyopathy treatment.
DATA SOURCES
In addition to clinical guidelines, package inserts, and general reviews, we searched PubMed using the term mavacamten from inception to June 11, 2022.
STUDY SELECTION AND DATA EXTRACTION
English language studies describing mavacamten's mechanism of action, pharmacokinetics, drug interactions, clinical and economic outcomes, and adverse events.
DATA SYNTHESIS
Mavacamten reduces left ventricular outflow obstruction and New York Heart Association functional class while improving Kansas City Cardiomyopathy Questionnaire-Clinical Summary Scores in patients with obstructive hypertrophic cardiomyopathy. With an acquisition cost of $245.20 per capsule, it would cost $1.2 million for every additional quality-adjusted life year. In those with unobstructive hypertrophic cardiomyopathy, there were improvements in -terminal probrain natriuretic peptide and high-sensitivity cardiac troponin biochemical markers. Mavacamten is a substrate for CYP2C19 and CYP3A4, and a CYP enzyme inducer.
RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE
Patients with obstructive hypertrophic cardiomyopathy and an ejection fraction ≥55% have a new option if they remain symptomatic despite maximally tolerated β-blocker or non-dihydropyridine calcium channel blocker therapy. It is an alternative to disopyramide therapy, which has poor patient tolerance, or septal reduction therapies, which are invasive. However, mavacamten is not cost-effective and its role in nonobstructive hypertrophic cardiomyopathy is not well established.
CONCLUSIONS
Mavacamten is a new option for patients with refractory obstructive hypertrophic cardiomyopathy and an ejection fraction ≥55% but its pricing makes therapy not cost-effective. Final health outcomes are not fully elucidated and additional studies are needed to determine long-term effects.
Topics: Humans; Benzylamines; Cardiomyopathy, Hypertrophic; Cytochrome P-450 CYP3A; Drug Tolerance
PubMed: 35950315
DOI: 10.1177/10600280221117812 -
Journal of Cardiac Failure Nov 2023
Topics: Humans; Disopyramide; Sequoia; Heart Failure; Anti-Arrhythmia Agents; Cardiomyopathy, Hypertrophic
PubMed: 37473912
DOI: 10.1016/j.cardfail.2023.07.003 -
International Journal of Cardiology Dec 2019Significant left-ventricular outflow tract obstruction (LVOTO) in hypertrophic cardiomyopathy (HCM) may result in symptoms and is associated with adverse outcomes....
BACKGROUND
Significant left-ventricular outflow tract obstruction (LVOTO) in hypertrophic cardiomyopathy (HCM) may result in symptoms and is associated with adverse outcomes. Although disopyramide can reduce resting gradients, nearly 30% of HCM patients do not respond. We sought to study the clinical and echocardiographic variables associated with disopyramide-induced LVOT-gradient reduction.
METHODS
Forty-one disopyramide-treated HCM patients (average daily-dose 305 mg) were subdivided into two groups: (1) nineteen responders, with a reduction of LVOT-gradients of at least 30% from baseline, and (2) twenty-two non-responders, in whom LVOT-gradients did not change or increased following treatment. All patients had a thorough clinical and echocardiographic assessment pre- and post-treatment initiation.
RESULTS
Patients who responded to disopyramide had better pretreatment left ventricular (LV) systolic function (LV ejection fraction of 67.9 ± 5.6% vs. 59.7 ± 5.8%, p = 0.0001), better LV global longitudinal strain (-17.9 ± 2.3% vs. -16.1 ± 2.5%, p = 0.048), less mitral regurgitation, smaller LV size (indexed LV end-systolic volume of 16.2 ± 5.1 ml/m vs. 23.2 ± 6.8 ml/m, p = 0.001), and lower LV maximal wall thickness (17.2±3 mm vs.19.2 ± 3.4 mm, p = 0.046). Baseline left atrial (LA) volumes were significantly lower in the responders, with higher indices of LA ejection fraction (62 ± 11.2% vs. 50.5 ± 12.2%, p = 0.005), systolic LA strain (34 ± 12.4% vs. 25.8 ± 10.6%, p = 0.04), and LA strain-rate (1.34 ± 0.49%/sec vs. 0.99 ± 0.24%/sec, p = 0.012). In multivariable analysis, the presence of reduced LV systolic function and systolic LA strain-rate remained independently associated with poor response to disopyramide.
CONCLUSIONS
Obstructive HCM patients with more severe disease at baseline tend to respond less to disopyramide treatment. In those patients, early referral for alcohol septal ablation or myectomy surgery should be considered.
Topics: Aged; Atrial Function; Cardiomyopathy, Hypertrophic; Cohort Studies; Disopyramide; Echocardiography; Female; Humans; Male; Middle Aged; Stroke Volume; Treatment Outcome; Ventricular Function, Left; Ventricular Outflow Obstruction; Voltage-Gated Sodium Channel Blockers
PubMed: 31615649
DOI: 10.1016/j.ijcard.2019.09.066 -
Pharmaceutics Feb 2023Cardiomyopathy is associated with structural and functional abnormalities of the ventricular myocardium and can be classified in two major groups: hypertrophic (HCM) and...
Cardiomyopathy is associated with structural and functional abnormalities of the ventricular myocardium and can be classified in two major groups: hypertrophic (HCM) and dilated (DCM) cardiomyopathy. Computational modeling and drug design approaches can speed up the drug discovery and significantly reduce expenses aiming to improve the treatment of cardiomyopathy. In the SILICOFCM project, a multiscale platform is developed using coupled macro- and microsimulation through finite element (FE) modeling of fluid-structure interactions (FSI) and molecular drug interactions with the cardiac cells. FSI was used for modeling the left ventricle (LV) with a nonlinear material model of the heart wall. Simulations of the drugs' influence on the electro-mechanics LV coupling were separated in two scenarios, defined by the principal action of specific drugs. We examined the effects of Disopyramide and Dygoxin which modulate Ca transients (first scenario), and Mavacamten and 2-deoxy adenosine triphosphate (dATP) which affect changes of kinetic parameters (second scenario). Changes of pressures, displacements, and velocity distributions, as well as pressure-volume (P-V) loops in the LV models of HCM and DCM patients were presented. Additionally, the results obtained from the SILICOFCM Risk Stratification Tool and PAK software for high-risk HCM patients closely followed the clinical observations. This approach can give much more information on risk prediction of cardiac disease to specific patients and better insight into estimated effects of drug therapy, leading to improved patient monitoring and treatment.
PubMed: 36986654
DOI: 10.3390/pharmaceutics15030793 -
Cardiology and Therapy Jun 2022There is limited evidence on therapies for obstructive hypertrophic cardiomyopathy (HCM), and data regarding treatment patterns and cost are scarce. This study assessed...
INTRODUCTION
There is limited evidence on therapies for obstructive hypertrophic cardiomyopathy (HCM), and data regarding treatment patterns and cost are scarce. This study assessed treatment patterns and economic outcomes in patients with symptomatic obstructive HCM.
METHODS
Adults with symptomatic obstructive HCM as per study design and treated with pharmacotherapies [beta blockers (BBs), calcium channel blockers (CCBs), BB + CCB, or disopyramide] or procedures (septal reduction therapy, heart transplantation, implantable cardioverter-defibrillator, and pacemaker implantation) were identified from the IBM® MarketScan® Commercial and Medicare Supplemental database (January 2009-March 2019). Patients had 12-month continuous eligibility before and after (study period) treatment initiation (index treatment). Healthcare resource utilization (HRU), costs, and treatment changes were assessed.
RESULTS
Of the 4883 patients included in the analysis, 85% received pharmacotherapies (BB 52.5%; CCB 11.7%; BB + CCB 17.7%; disopyramide 2.4%) and 15.7% underwent procedures. During the study period, 38, 34, and 100% of all patients had ≥ 1 inpatient stay, emergency room (ER) visit, and outpatient visit, respectively; mean total healthcare costs were US$53,053. Patients undergoing procedures had the highest HRU and costs across groups. Among patients receiving pharmacotherapies, HRU was lowest with BBs and highest with disopyramide. Treatment changes were observed in 43.8% of patients receiving pharmacotherapies.
CONCLUSIONS
Patients experienced high rates of treatment changes, and the economic burden associated with symptomatic obstructive HCM increased as therapy escalated. More effective therapies are needed to stabilize or decrease the economic burden of obstructive HCM.
PubMed: 35230625
DOI: 10.1007/s40119-022-00257-7 -
Giornale Italiano Di Cardiologia (2006) Oct 2023Hypertrophic cardiomyopathy is the most common genetic cardiomyopathy. Main complications include the development of arrhythmias and heart failure, and the latter may be... (Review)
Review
Hypertrophic cardiomyopathy is the most common genetic cardiomyopathy. Main complications include the development of arrhythmias and heart failure, and the latter may be triggered by left ventricular outflow tract obstruction. The treatment of left ventricular outflow tract obstruction includes pharmacological therapies (beta-blockers, calcium channel blockers, disopyramide) and septal reduction therapies (alcohol septal ablation, surgical myectomy). Myosin inhibitors represent a new therapeutic opportunity and in recent clinical trials proved effective in symptom relief, improvement of functional capacity and quality of life in patients with obstructive hypertrophic cardiomyopathy. In this narrative review we will summarize the available and under development therapeutic approaches for hypertrophic cardiomyopathy.
Topics: Humans; Quality of Life; Cardiomyopathy, Hypertrophic; Heart Failure; Ventricular Outflow Obstruction, Left
PubMed: 37767831
DOI: 10.1714/4100.40979 -
Molecular Pharmaceutics Jun 2024α-Acid glycoprotein (AGP) is a primary binding protein for many basic drugs in plasma. The number of drugs that bind to AGP, such as molecular target anticancer drugs,...
α-Acid glycoprotein (AGP) is a primary binding protein for many basic drugs in plasma. The number of drugs that bind to AGP, such as molecular target anticancer drugs, has been continuously increasing. Since the plasma level of AGP fluctuates under various pathological conditions such as inflammation, it is important to evaluate the contribution of AGP to drug pharmacokinetics. Here, we generated conventional AGP-knockout (AGP-KO) mice and used them to evaluate the contribution of AGP. The pharmacokinetics of drugs that bind to two AGP variants (F1*S or A variants) or albumin were evaluated. Imatinib (a F1*S-binding drug) and disopyramide (an A-binding drug) or ibuprofen (an albumin-binding drug) were administered to wild-type (WT) and AGP-KO. The plasma level of imatinib and disopyramide decreased rapidly in AGP-KO as compared to WT. In AGP-KO, AUC and were decreased, then C was increased. Compared with disopyramide, imatinib pharmacokinetics showed more marked changes in AGP-KO as compared to WT. The results seemed to be due to the difference in plasma level of each AGP variant (F1*S:A = 2-3:1). No differences were observed in ibuprofen pharmacokinetics between the WT and AGP-KO mice. In vitro experiments using plasma from WT and AGP-KO showed that unbound fractions of imatinib and disopyramide were higher in AGP-KO. These results suggest that the rapid elimination of imatinib and disopyramide in AGP-KO could be due to decreased protein binding to AGP. Taken together, the AGP-KO mouse could be a potential animal model for evaluating the contribution of AGP to the pharmacokinetics of various drugs.
PubMed: 38862418
DOI: 10.1021/acs.molpharmaceut.3c00866