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Rouskas P, Zegkos T, Ntelios D, Gossios T, Parcharidou D, Papanastasiou CA, Karamitsos T, Vassilikos V, Kouskouras K, Efthimiadis GK. Prevalence, characteristics, and natural history of apical phenotype in a large cohort of patients with hypertrophic cardiomyopathy. Hellenic J Cardiol 2023; 73:8-15. [PMID: 36775018 DOI: 10.1016/j.hjc.2023.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 02/02/2023] [Accepted: 02/08/2023] [Indexed: 02/13/2023] Open
Abstract
BACKGROUND Apical hypertrophic cardiomyopathy (ApHCM) is a variant of hypertrophic cardiomyopathy (HCM) with distinct imaging and clinical characteristics. Data on the prognosis of this HCM subgroup appear conflicting. Our study aims to clarify the natural history of ApHCM and identify predictors of outcomes. MATERIALS AND METHODS A total of 856 patients with HCM were retrospectively examined. ApHCM was defined as asymmetric left ventricular hypertrophy confined predominantly at the apex, either isolated (pure ApHCM type) or with co-existent hypertrophy of the interventricular septum (mixed ApHCM). Echocardiographic, clinical, and survival data were compared between individuals with ApHCM and non-ApHCM. RESULTS A total of 143 (16.7%) patients were diagnosed with ApHCM. Compared with non-ApHCM, subjects with apical HCM were diagnosed at an older age and had better echocardiographic indices and more comorbidities at baseline. Apical aneurysms were more prevalent among the ApHCM phenotype (6.3% vs. 1.7%, p = 0.003). During a mean follow-up of 6 ± 3 years, ApHCM was characterized by lower all-cause, cardiovascular, heart failure-related mortality, and ventricular arrhythmic events compared with non-ApHCM. Multivariate analysis identified atrial fibrillation and HCM risk-sudden cardiac death (SCD) as independent predictors of the composite outcome of overall mortality and hospitalizations for cardiovascular reasons (hazard ratio [HR] 4.3, 95% confidence interval [CI] 1.9-9.5 for atrial fibrillation and HR 1.2, 95% CI 1.02-1.3 for HCM risk-SCD) in ApHCM. CONCLUSIONS ApHCM exhibited a lower rate of all-cause mortality and arrhythmic events in the middle-aged population of patients with HCM. Atrial fibrillation and HCM risk-sudden cardiac death were independent predictors of a composite of overall mortality and cardiovascular hospitalizations among those with ApHCM.
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Affiliation(s)
- Pavlos Rouskas
- First Cardiology Department, AHEPA University Hospital, Thessaloniki, Greece
| | - Thomas Zegkos
- First Cardiology Department, AHEPA University Hospital, Thessaloniki, Greece.
| | - Dimitris Ntelios
- First Cardiology Department, AHEPA University Hospital, Thessaloniki, Greece
| | - Thomas Gossios
- First Cardiology Department, AHEPA University Hospital, Thessaloniki, Greece
| | | | | | | | - Vassilis Vassilikos
- Third Cardiology Department, HIPPOKRATION University Hospital, Thessaloniki, Greece
| | - Kostantinos Kouskouras
- Department of Radiology, University General Hospital of Thessaloniki AHEPA, Thessaloniki, Greece
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Santoro F, Mango F, Mallardi A, D'Alessandro D, Casavecchia G, Gravina M, Correale M, Brunetti ND. Arrhythmic Risk Stratification among Patients with Hypertrophic Cardiomyopathy. J Clin Med 2023; 12:jcm12103397. [PMID: 37240503 DOI: 10.3390/jcm12103397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 05/07/2023] [Accepted: 05/09/2023] [Indexed: 05/28/2023] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is a cardiac muscle disorder characterized by generally asymmetric abnormal hypertrophy of the left ventricle without abnormal loading conditions (such as hypertension or valvular heart disease) accounting for the left ventricular wall thickness or mass. The incidence of sudden cardiac death (SCD) in HCM patients is about 1% yearly in adults, but it is far higher in adolescence. HCM is the most frequent cause of death in athletes in the Unites States of America. HCM is an autosomal-dominant genetic cardiomyopathy, and mutations in the genes encoding sarcomeric proteins are identified in 30-60% of cases. The presence of this genetic mutation carries more than 2-fold increased risk for all outcomes, including ventricular arrhythmias. Genetic and myocardial substrate, including fibrosis and intraventricular dispersion of conduction, ventricular hypertrophy and microvascular ischemia, increased myofilament calcium sensitivity and abnormal calcium handling, all play a role as arrhythmogenic determinants. Cardiac imaging studies provide important information for risk stratification. Transthoracic echocardiography can be helpful to evaluate left ventricular (LV) wall thickness, LV outflow-tract gradient and left atrial size. Additionally, cardiac magnetic resonance can evaluate the prevalence of late gadolinium enhancement, which when higher than 15% of LV mass is a prognostic maker of SCD. Age, family history of SCD, syncope and non-sustained ventricular tachycardia at Holter ECG have also been validated as independent prognostic markers of SCD. Arrhythmic risk stratification in HCM requires careful evaluation of several clinical aspects. Symptoms combined with electrocardiogram, cardiac imaging tools and genetic counselling are the modern cornerstone for proper risk stratification.
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Affiliation(s)
- Francesco Santoro
- Cardiology Unit, Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy
| | - Federica Mango
- Cardiology Unit, Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy
| | - Adriana Mallardi
- Cardiology Unit, Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy
| | - Damiano D'Alessandro
- Cardiology Unit, Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy
| | - Grazia Casavecchia
- Cardiology Unit, Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy
| | - Matteo Gravina
- Radiology Unit, University Polyclinic Hospital of Foggia, 71100 Foggia, Italy
| | - Michele Correale
- Cardiology Unit, Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy
| | - Natale Daniele Brunetti
- Cardiology Unit, Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy
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Abstract
PURPOSE OF REVIEW Hypertrophic cardiomyopathy (HCM) is one of the leading causes of sudden cardiac death (SCD) in younger people and athletes. It is crucial to identify the risk factors for SCD in individuals with HCM. This review, based on recent systematic literature studies, will focus on the risk factors for SCD in patients with HCM. RECENT FINDINGS An increasing number of studies have further explored the risk factors for SCD in patients with HCM, and new risk markers have emerged accordingly. In addition, more accurate SCD risk estimation and stratification methods have been proposed and continuously improved. SUMMARY The identification of independent risk factors for HCM-related SCD would likely contribute to risk stratification. However, it is difficult to predict SCD with absolute certainty, as the annual incidence of SCD in adult patients with HCM is approximately 1%. The review discusses the established risk factors, such as a family history of SCD, unexplained syncope and some new risk factors. Taken together, the findings of this review demonstrate that there is a need for further research on individual risk factors and that SCD risk stratification in HCM patients remains a clinical challenge.
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Affiliation(s)
- Ying Hong
- Department of Cardiology, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
- Department of Cardiology, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China
- Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, Sichuan, China
| | - Wilber W. Su
- Department of Cardiology, Banner-University Medical Center, Phoenix, Arizona, USA
| | - Xiaoping Li
- Department of Cardiology, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China
- Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, Sichuan, China
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Efthimiadis G, Zegkos T, Parcharidou D, Ntelios D, Panagiotidis T, Gossios T, Karvounis H. A simple algorithm for a clinical step-by-step approach in the management of hypertrophic cardiomyopathy. Future Cardiol 2021; 17:1395-1405. [PMID: 33615852 DOI: 10.2217/fca-2020-0230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is the most common inherited heart disease with an autosomal dominant pattern and a reported prevalence of about 0.2%. In this review, we present a simple algorithm for the management of first diagnosed HCM patients. Initially, the clinical examination, medical and detailed family history and the ECG are essential. The etiological diagnosis of left ventricular hypertrophy is important in order to differentiate HCM due to sarcomeric genes mutation from other phenocopies, such as cardiac amyloidosis. The next step consists of the cardiovascular imaging and ambulatory electrocardiography. Cardiopulmonary exercise testing may also be considered if available. All of the above provide evidence for the critical step of the risk stratification of patients for sudden cardiac death. The therapeutic strategy, with respect to obstructive and nonobstructive disease, arrhythmias and end-stage HCM is also described.
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Affiliation(s)
- Georgios Efthimiadis
- 1st Cardiology department, Laboratory of Cardiomyopathies and Inherited Cardiac Diseases, AHEPA University hospital, Thessaloniki 54636, Greece
| | - Thomas Zegkos
- 1 Cardiology department, Laboratory of Cardiomyopathies and Inherited Cardiac Diseases, AHEPA University hospital, Thessaloniki 54636, Greece
| | - Despoina Parcharidou
- 1 Cardiology department, Laboratory of Cardiomyopathies and Inherited Cardiac Diseases, AHEPA University hospital, Thessaloniki 54636, Greece
| | - Dimitris Ntelios
- 1 Cardiology department, Laboratory of Cardiomyopathies and Inherited Cardiac Diseases, AHEPA University hospital, Thessaloniki 54636, Greece
| | - Theofilos Panagiotidis
- 1 Cardiology department, Laboratory of Cardiomyopathies and Inherited Cardiac Diseases, AHEPA University hospital, Thessaloniki 54636, Greece
| | - Thomas Gossios
- Barts Heart Centre, St Bartholomew's Hospital, W Smithfield, London, EC1A 7BE, UK
| | - Haralambos Karvounis
- 1 Cardiology department, Laboratory of Cardiomyopathies and Inherited Cardiac Diseases, AHEPA University hospital, Thessaloniki 54636, Greece
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Corona-Villalobos CP, Sorensen LL, Pozios I, Chu L, Eng J, Abraham MR, Abraham TP, Kamel IR, Zimmerman SL. Left ventricular wall thickness in patients with hypertrophic cardiomyopathy: a comparison between cardiac magnetic resonance imaging and echocardiography. Int J Cardiovasc Imaging 2016; 32:945-54. [DOI: 10.1007/s10554-016-0858-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 02/10/2016] [Indexed: 01/09/2023]
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Liu L, Tuo S, Zhang J, Zuo L, Liu F, Hao L, Sun Y, Yang L, Shao H, Qi W, Zhou X, Ge S. Reduction of left ventricular longitudinal global and segmental systolic functions in patients with hypertrophic cardiomyopathy: Study of two-dimensional tissue motion annular displacement. Exp Ther Med 2014; 7:1457-1464. [PMID: 24926326 PMCID: PMC4043569 DOI: 10.3892/etm.2014.1617] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2013] [Accepted: 02/05/2014] [Indexed: 11/18/2022] Open
Abstract
The early detection of abnormal left ventricular systolic functions in patients with hypertrophic cardiomyopathy (HCM) remains a challenge. The aim of this study was to identify a novel method for the assessment of left ventricular systolic function in patients with HCM. A total of 65 patients with HCM were included in this study. The patients were divided into obstructive HCM (HOCM; 16 cases) and non-obstructive HCM (NOHCM; 49 cases) groups. The healthy control group comprised 48 participants. Two-dimensional (2D) speckle-tracking technology was used to measure the left ventricular global and segmental longitudinal strains and mitral annular displacement (MADs). Compared with healthy control group, the six segmental strains and the global strain of the left ventricle (LSglobal) increased while six segmental MADs and MADglobal of the mitral annulus decreased in the HOCM and NOHCM groups (P<0.05). In addition, the six segmental MADs of the mitral annulus were significantly negatively correlated with the six segmental strains of the left ventricle (r=−0.744 to −0.647, P<0.001). MADglobal was significantly negatively correlated with LSglobal (r=−0.857, P<0.001). The tissue motion annular displacement (TMAD) at the midpoint was significantly negatively correlated with LSglobal (r=−0.871, P<0.001). The 2D TMAD technique of measuring MAD was feasible and practically approachable for rapidly evaluating the left ventricular longitudinal global and segmental systolic functions of patients with HCM.
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Affiliation(s)
- Liwen Liu
- Department of Ultrasound, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
| | - Shengjun Tuo
- Department of Ultrasound, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China ; Department of Ultrasound, Yan'an People's Hospital, Yan'an, Shaanxi 716000, P.R. China
| | - Jianlei Zhang
- Department of Ultrasound, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China ; Department of Ultrasound, Yan'an People's Hospital, Yan'an, Shaanxi 716000, P.R. China
| | - Lei Zuo
- Department of Ultrasound, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
| | - Fang Liu
- Department of Ultrasound, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
| | - Lili Hao
- Department of Ultrasound, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
| | - Yandan Sun
- Department of Ultrasound, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
| | - Liping Yang
- Department of Ultrasound, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
| | - Hong Shao
- Department of Ultrasound, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
| | - Wei Qi
- Department of Ultrasound, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
| | - Xiaodong Zhou
- Department of Ultrasound, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
| | - Shuping Ge
- Department of Cardiology, The Heart Center, St. Christopher's Hospital for Children, Drexel University College of Medicine, Philadelphia, PA 19134, USA
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Abstract
Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiac disorder. This autosomal dominant condition is defined by left ventricular hypertrophy and associated with functional limitation and premature death. In fact, many individuals are asymptomatic and the annual mortality in most modern series is 1% or less. However, severe symptoms may develop at any age, and the risk of premature death from arrhythmia, stroke, and progressive systolic impairment may complicate asymptomatic disease. The clinical management of patients with HCM therefore encompasses (1) genetic counseling including discussion of indications for genetic testing and cascade family screening, (2) assessment of prognostic risk from ventricular arrhythmia, stroke, and heart failure, and (3) symptom management. This article describes the interventional treatments in the management of severe symptoms associated with left ventricular outflow tract obstruction (LVOTO).
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Affiliation(s)
- Saidi A Mohiddin
- The Heart Muscle Disease Clinic, London Chest Hospital, Barts and The London NHS Trust, London, UK.
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Ostman-Smith I, Wisten A, Nylander E, Bratt EL, Granelli ADW, Oulhaj A, Ljungström E. Electrocardiographic amplitudes: a new risk factor for sudden death in hypertrophic cardiomyopathy. Eur Heart J 2009; 31:439-49. [PMID: 19897498 PMCID: PMC2821628 DOI: 10.1093/eurheartj/ehp443] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Aims Assessment of ECG-features as predictors of sudden death in adults with hypertrophic cardiomyopathy (HCM). Methods and results ECG-amplitude sums were measured in 44 normals, 34 athletes, a hospital-cohort of 87 HCM-patients, and 29 HCM-patients with sudden death or cardiac arrest (HCM-CA). HCM-patients with sudden death or cardiac arrest had substantially higher ECG-amplitudes than the HCM-cohort for limb-lead and 12-lead QRS-amplitude sums, and amplitude–duration products (P = 0.00003–P = 0.000002). Separation of HCM-CA from the HCM-cohort is obtained by limb-lead QRS-amplitude sum ≥7.7 mV (odds ratio 18.8, sensitivity 87%, negative predictive value (NPV) 94%, P < 0.0001), 12-lead amplitude–duration product ≥2.2 mV s (odds ratio 31.0, sensitivity 92%, NPV 97%, P < 0.0001), and limb-lead amplitude–duration product ≥0.70 mV s (odds ratio 31.5, sensitivity 93%, NPV 96%, P < 0.0001). Sensitivity in HCM-patients <40 years is 90, 100, and 100% for those ECG-variables, respectively. Qualitative analysis showed correlation with cardiac arrest for pathological T-wave-inversion (P = 0.0003), ST-depression (P = 0.0010), and dominant S-wave in V4 (P = 0.0048). A risk score is proposed; a score ≥6 gives a sensitivity of 85% but a higher positive predictive value than above measures. Optimal separation between HCM-CA <40 years and athletes is obtained by a risk score ≥6 (odds ratio 345, sensitivity 85%, specificity 100%, P < 0.0001). Conclusion Twelve-lead ECG is a powerful instrument for risk-stratification in HCM.
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Affiliation(s)
- Ingegerd Ostman-Smith
- Division of Paediatrics, Department of Clinical Sciences, Sahlgrenska Academy, Gothenburg University, Queen Silvia Childreńs Hospital, SE-416 85 Gothenburg, Sweden.
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9
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Graham-Cryan MA, Rowe G, Hathaway L, Biddle S, Tripodi D, Fananapazir L. Obstructive Hypertrophic Cardiomyopathy. ACTA ACUST UNITED AC 2008; 19:133-40. [PMID: 15539974 DOI: 10.1111/j.0889-7204.2003.03400.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hypertrophic cardiomyopathy (HCM) is a primary disease of cardiac muscle characterized by a thickening of the left ventricular wall and often predominantly affecting the interventricular septum. This paper presents a case study of a 53-year-old female with a dynamic and obstructive form of HCM. The study includes a case presentation, clinical findings, investigations, and management. Patient findings were obtained before and after alcohol septal ablation, a novel interventional therapy. The article reviews the various forms of HCM and describes the currently available treatment modalities for obstructive HCM. Further research will be necessary to determine the comparative efficacy between past, present, and future therapies.
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Affiliation(s)
- Melissa A Graham-Cryan
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, 10 Center Drive MSC 1650, Room 7B-15, Bethesda, MD 20892-1650, USA.
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10
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Kim YJ, Choi BW, Hur J, Lee HJ, Seo JS, Kim TH, Choe KO, Ha JW. Delayed enhancement in hypertrophic cardiomyopathy: Comparison with myocardial tagging MRI. J Magn Reson Imaging 2008; 27:1054-60. [DOI: 10.1002/jmri.21366] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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11
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Ostman-Smith I, Wettrell G, Keeton B, Riesenfeld T, Holmgren D, Ergander U. Echocardiographic and electrocardiographic identification of those children with hypertrophic cardiomyopathy who should be considered at high-risk of dying suddenly. Cardiol Young 2005; 15:632-42. [PMID: 16297259 DOI: 10.1017/s1047951105001824] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/16/2005] [Indexed: 11/07/2022]
Abstract
BACKGROUND Hypertrophic cardiomyopathy is a common cause of sudden death in children. In this study, we aimed to identify clinical measures for stratification of this risk in childhood. PATIENTS AND METHODS By means of a retrospective cohort study from six regional centres of paediatric cardiology, we identified 128 patients with hypertrophic cardiomyopathy presenting below 19 years of age, with a mean follow-up of 10.8 years. Of the patients, 31 had died, 16 suddenly, with a median age at sudden death of 13.3 years. RESULTS Cox regression shows that electrocardiographic voltages, analysed as the sum of the R and S waves in all six limb leads (p equal to 0.001), and septal thickness expressed as proportion of the 95th centile for age (p equal to 0.036), were independent predictors of sudden death. When the sum of the R and S waves is over 10 millivolts, the odds ratio for sudden death was 8.4, with 95% confidence intervals from 2.2 to 33.7 (p equal to 0.0012), and finding a septal thickness over 190% of 95th centile for age gives an odds ratio of 6.2, with confidence intervals from 1.5 to 25.1 (p equal to 0.011). Noonan's syndrome, with a p value equal to 0.043, and the ratio of the left ventricular wall to its cavity in diastole, with a p value equal to 0.005, were independent predictors of death in cardiac failure, with a ratio of the mural thickness to the dimension of the cavity over 0.30 giving an odds ratio of 36.0, with confidence limits from 4.2 to 311, and a p value equal to 0.00009. At follow-up, patients deemed to be at a high risk of dying suddenly were identified by the combination of the sum of the R and S waves greater than 10 millivolts and septal thickness over 190%, with a sensitivity of 91%, specificity of 78%, positive predictive value of 50%, and a negative predictive value of 97%. CONCLUSIONS Children at high risk of dying suddenly with hypertrophic cardiomyopathy, with a subsequent annual mortality of 6.6%, can be distinguished at the time of diagnosis from those patients having a low risk of sudden death, the latter with an annual mortality of 0.27%.
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Affiliation(s)
- Ingegerd Ostman-Smith
- Division of Paediatric Cardiology, Queen Silvia Children's Hospital, Gothenburg, Sweden.
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Abstract
This article reviews medicolegal issues in sports medicine. Nonmusculoskeletal medical conditions discussed include cardiac abnormalities, heat illness, and concussion in the athlete. Musculoskeletal injuries with the greatest potential for litigation, knee dislocation, and cervical spine trauma, are also reviewed. We provide legal case examples and discuss evaluation and treatment strategies to assist the medical team in the care of athletes.
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Affiliation(s)
- Alison K Sanders
- Duke Sports Medicine, 317 Finch-Yeager Building, Durham, NC 27708, USA
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13
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Restrepo CS, Largoza A, Lemos DF, Diethelm L, Koshy P, Castillo P, Gomez R, Moncada R, Pandit M. CT and MR imaging findings of benign cardiac tumors. Curr Probl Diagn Radiol 2005; 34:12-21. [PMID: 15644859 DOI: 10.1067/j.cpradiol.2004.10.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This imaging review describes the appearance of benign cardiac tumors on CT and MRI. Although rare, benign tumors outnumber their primary malignant counterparts three to one. Since mortality varies directly with invasion, identifying the neoplasm at an early stage helps focus treatment, especially in benign cases, which generally respond well to surgical resection. In adults and children, myxomas and rhabdomyomas, respectively, represent the most common benign tumors, which can be grouped into tissue-specific subtypes, such as rhabdomyomas, fibromas, lipomas, teratomas, etc. Besides their variable prevalence in particular age groups, these tumors also differ with regard to their gender predilection, location, and number. For example, myxomas appear predominantly in women and generally as a solitary mass in the left or right atrium, whereas rhabdomyomas present equally in boys and girls and chiefly as multiple masses in the ventricles. Despite their differences, however, both types share an association with heritable syndromes like the Carney complex for myxomas and tuberous sclerosis for rhabdomyomas. As with all cardiac tumors, echocardiographic findings usually suggest the initial diagnosis but cross-sectional imaging with CT and MRI can help resolve diagnostically challenging cases. For example, with its direct multiplanar capability, excellent contrast resolution, and large field of view, MRI permits a detailed examination of the entire mediastinum, helping to rule out an equivocal mass on echocardiography. Through dynamic techniques, MRI, in addition to morphologic characterization, can depict the pathophysiological effects of these tumors, for instance, with regard to myocardial contraction, valvular function, or blood flow.
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Affiliation(s)
- Carlos S Restrepo
- Department of Radiology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA.
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14
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Abstract
Objective:To describe the underlying conditions that predispose athletes to sudden cardiac death (SCD) and review signs and symptoms that indicate an athlete is at risk.Data Sources:MEDLINE, theLos Angeles TimesandTriathlon Timesarchives, and other sources identified in the references of articles initially located therein. A total of 43 references were included.Conclusions:Most cases of SCD in younger athletes (≤35 years) are attributable to multiple hereditary conditions, with familial hyper-trophic cardiomyopathy being the primary cause, whereas the major cause of SCD in older athletes (>35 years) is coronary artery disease. Health-care professionals evaluating athletes should pay particular attention to past medical and family history. Items in an athlete’s screening that suggest increased risk include a history of chest pain, syncope, excessive shortness of breath, irregular heart rate or murmur, or a history of SCD in an immediate family member.
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15
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Earing MG, Ackerman MJ, O'Leary PW. Diastolic ventricular dysfunction as a marker for hypertrophic cardiomyopathy in a family with a novel alpha-tropomyosin mutation. J Am Soc Echocardiogr 2003; 16:698-702. [PMID: 12778034 DOI: 10.1016/s0894-7317(03)00285-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Early identification of familial cases of hypertrophic cardiomyopathy (HCM) depends on screening echocardiography, but hypertrophy may not be the most sensitive marker for the disease. We report the echocardiographic findings of a family with HCM and a newly reported mutation in the gene (TPM1) encoding alpha-tropomyosin.Methods and results An 8-year-old girl had sudden cardiac death, and was found to have HCM and a novel L185R-TPM1 mutation on postmortem examination. Screening echocardiograms and DNA analyses were performed on her family. Of the 5 remaining family members, 3 were genetically affected. Those without the TPM1 mutation had normal echocardiographic results. The only echocardiographic finding that identified all 3 of the gene-positive family members was an abnormal left ventricular diastolic filling pattern. CONCLUSION Abnormal left ventricular diastolic filling patterns, indicating diastolic dysfunction, may provide an early marker for the diagnosis of familial HCM in children, even in the absence of left ventricular hypertrophy.
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Affiliation(s)
- Michael G Earing
- Departments of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
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16
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Hwang JJ, Allen PD, Tseng GC, Lam CW, Fananapazir L, Dzau VJ, Liew CC. Microarray gene expression profiles in dilated and hypertrophic cardiomyopathic end-stage heart failure. Physiol Genomics 2002; 10:31-44. [PMID: 12118103 DOI: 10.1152/physiolgenomics.00122.2001] [Citation(s) in RCA: 182] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Despite similar clinical endpoints, heart failure resulting from dilated cardiomyopathy (DCM) or hypertrophic cardiomyopathy (HCM) appears to develop through different remodeling and molecular pathways. Current understanding of heart failure has been facilitated by microarray technology. We constructed an in-house spotted cDNA microarray using 10,272 unique clones from various cardiovascular cDNA libraries sequenced and annotated in our laboratory. RNA samples were obtained from left ventricular tissues of precardiac transplantation DCM and HCM patients and were hybridized against normal adult heart reference RNA. After filtering, differentially expressed genes were determined using novel analyzing software. We demonstrated that normalization for cDNA microarray data is slide-dependent and nonlinear. The feasibility of this model was validated by quantitative real-time reverse transcription-PCR, and the accuracy rate depended on the fold change and statistical significance level. Our results showed that 192 genes were highly expressed in both DCM and HCM (e.g., atrial natriuretic peptide, CD59, decorin, elongation factor 2, and heat shock protein 90), and 51 genes were downregulated in both conditions (e.g., elastin, sarcoplasmic/endoplasmic reticulum Ca2+-ATPase). We also identified several genes differentially expressed between DCM and HCM (e.g., alphaB-crystallin, antagonizer of myc transcriptional activity, beta-dystrobrevin, calsequestrin, lipocortin, and lumican). Microarray technology provides us with a genomic approach to explore the genetic markers and molecular mechanisms leading to heart failure.
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Affiliation(s)
- Juey-Jen Hwang
- Cardiovascular Genome Unit, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston 02115, USA
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17
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Abstract
Recent data have emerged to help guide the use of implantable pacemakers and implantable defibrillators in patients who have hypertrophic cardiomyopathy (HCM). Controlled studies of the use of dual chamber pacemakers to treat outflow tract obstruction in HCM have shown little benefit, and have raised the possibility that earlier favorable reports were demonstrating an element of placebo effect. In particular, there is no recent support for earlier claims of regression of ventricular hypertrophy from chronic dual chamber pacing. Several reports have added to our understanding of the risk factors for sudden death in HCM. A normal blood pressure response to exercise appears to identify a subset of patients at low risk for sudden death. In a recent study of a large number of HCM patients, the risk of sudden death was found to be directly proportional to the extent of left ventricular hypertrophy. There is accumulating evidence that the implantable defibrillator is highly effective in terminating malignant ventricular arrhythmias in HCM patients, and HCM patients thought to be at significant risk for sudden death should be offered defibrillator implantation.
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MESH Headings
- Arrhythmias, Cardiac/complications
- Arrhythmias, Cardiac/prevention & control
- Cardiac Pacing, Artificial
- Cardiomyopathy, Hypertrophic/complications
- Cardiomyopathy, Hypertrophic/physiopathology
- Cardiomyopathy, Hypertrophic/therapy
- Death, Sudden, Cardiac/prevention & control
- Defibrillators, Implantable
- Humans
- Pacemaker, Artificial
- Randomized Controlled Trials as Topic
- Risk Factors
- Treatment Outcome
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Affiliation(s)
- R A Freedman
- Arrhythmia Service, Cardiology Division, University of Utah Health Sciences Center, Salt Lake City, Utah, USA.
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18
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Olson TM, Doan TP, Kishimoto NY, Whitby FG, Ackerman MJ, Fananapazir L. Inherited and de novo mutations in the cardiac actin gene cause hypertrophic cardiomyopathy. J Mol Cell Cardiol 2000; 32:1687-94. [PMID: 10966831 DOI: 10.1006/jmcc.2000.1204] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mutations in genes encoding sarcomeric proteins cause hypertrophic cardiomyopathy (HCM). The sarcomeric protein actin plays a central, dual role in cardiac myocytes, generating contractile force by interacting with myosin and also transmitting force within and between cells. Two missense mutations in the cardiac actin gene (ACTC), postulated to impair force transmission, have been associated with familial dilated cardiomyopathy (DCM). Recently, a missense mutation in ACTC was found to cosegregate with familial HCM. To further test the hypothesis that mutations within functionally distinct domains of ACTC cause either DCM or HCM, we performed mutational analyses in 368 unrelated patients with familial or sporadic HCM. Single strand conformation polymorphism and sequence analyses of genomic DNA were performed. De novo mutations in ACTC were identified in two patients with sporadic HCM who presented with syncope in early childhood. Patients were heterozygous for missense mutations resulting in Pro164Ala and Ala331Pro amino acid substitutions, adjacent to regions of actin-actin and actin-myosin interaction, respectively. A mutation that cosegregated with familial HCM was also found, causing a Glu99Lys substitution in a weak actomyosin binding domain. The cardiac phenotype in many affected patients was characterized by an apical form of HCM. These findings support the hypothesis that a single amino acid substitution in actin causes either congestive heart failure or maladaptive cardiac hypertrophy, depending on its effect on actin structure and function.
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Affiliation(s)
- T M Olson
- Department of Pediatrics, Division of Pediatric Cardiology, Salt Lake City, UT 84113, USA.
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19
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Abstract
OBJECTIVE To identify the incidence, causes, and characteristics of sudden death at age 1-20 years. DESIGN A review of all deaths at age 1-20 years. Death certificates were obtained from the Office for National Statistics, and further information, where appropriate, from coroners, paediatricians, physicians, and pathologists. SETTING The resident population of one English health region in 1985-1994. RESULTS In a population of 806 500 children and adolescents aged 1-20 years there were 2523 deaths in 10 years. Medical causes accounted for 1017 deaths (40%); 1236 (49%) were unnatural, and 270 (11%) were sudden. These sudden deaths comprised 142 with a previous diagnosis, the commonest being epilepsy 49 (34%), cardiovascular disease 33 (23%), and asthma 30 (21%); 87 attributed to a cause discovered at necropsy, which was respiratory infection in 32 (37%), other infections in 17 (20%), and unsuspected cardiovascular abnormalities in 26 (30%); 41 remained unexplained. CONCLUSIONS Half of all sudden deaths in children or adolescents were attributed to an already diagnosed condition. Abnormalities identified at necropsy accounted for one third of sudden deaths. Undiagnosed hypertrophic cardiomyopathy caused less than one death per million person years in the population aged 1-20 years. Unexplained sudden death, which may be caused by primary cardiac arrhythmia, is probably about 10 times more common.
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Affiliation(s)
- C Wren
- Department of Paediatric Cardiology, Freeman Hospital, Newcastle upon Tyne NE7 7DN, UK
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20
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Devlin AM, Moore NR, Ostman-Smith I. A comparison of MRI and echocardiography in hypertrophic cardiomyopathy. Br J Radiol 1999; 72:258-64. [PMID: 10396215 DOI: 10.1259/bjr.72.855.10396215] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
This study compares MRI and echocardiography as imaging modalities in hypertrophic cardiomyopathy, with particular reference to measurement of left ventricular wall thickness and mass. 10 subjects underwent echocardiography and MRI. Contiguous 10 mm short axis 35 degrees flip angle cine gradient recalled echo MR images were acquired from the apex to the base of the left ventricle at 1.5 tesla. Standard M-mode and cross-sectional echocardiographic views of the left ventricle were obtained. Excellent agreement between measurements occurred with MRI and M-mode echocardiographic assessment of the thickness of the anterior interventricular septum (95% limits of agreement -1.5 to +1.5 mm). Other comparisons of MRI vs M-mode echocardiographic measurements had the following limits of agreement: posterior free wall -3.3 to +2.9 mm; end-diastolic dimension -5 to +8 mm, left ventricular mass -291 to +55.5 g. Comparing MRI with cross-sectional echocardiographic measurements, the limits of agreement were: anterior interventricular septum -2.4 to +1.7 mm, posterior interventricular septum -2.4 to +2.9 mm, posterior free wall -3.4 to +2.5 mm, anterior free wall -2.4 to +1.7 mm, end-diastolic dimension -4.1 to +8 mm. MRI estimates of LVM in systole vs diastole showed good agreement with 95% limits of agreement of -20 to +17 g, with excellent interobserver variability in diastole (-9 to +5 g) and in systole (-7 to +12 g). In conclusion, MRI is superior to echocardiography for the quantification of ventricular mass in the abnormal left ventricle because it does not make invalid geometrical assumptions. Comparisons of wall thickness show greater discrepancy with increasing distance from the echocardiographic transducer. This study suggests that sequential echocardiography could rationalize the need for MRI in left ventricular hypertrophy. A change in anterior septal thickness of > or = 3 mm on echocardiography merits a further MRI study.
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Affiliation(s)
- A M Devlin
- Department of Paediatrics, University of Oxford, UK
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21
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Abstract
Congestive heart failure (CHF) increases with age, but most CHF in the elderly is due to diastolic dysfunction with preserved systolic function. The etiology, pathophysiology, diagnosis, natural history, and treatment of hypertrophic and restrictive cardiomyopathies in the elderly are discussed as a paradigm for CHF with normal systolic function. Hypertrophic obstructive and hypertensive hypertrophic cardiomyopathies are compared and contrasted. As an example of a restrictive cardiomyopathy, the various types of amyloidosis and their clinical import in older patients are covered.
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Affiliation(s)
- S J Zieman
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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22
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Dutka DP, Donnelly JE, Nihoyannopoulos P, Oakley CM, Nunez DJ. Marked variation in the cardiomyopathy associated with Friedreich's ataxia. Heart 1999; 81:141-7. [PMID: 9922348 PMCID: PMC1728941 DOI: 10.1136/hrt.81.2.141] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
OBJECTIVE To document the cardiac phenotype associated with Friedreich's ataxia, a recessively inherited disorder characterised by spinocerebellar degeneration. SETTING Individuals with Friedreich's ataxia who accepted the invitation to participate in the study. HYPOTHESIS The cardiomyopathy associated with Friedreich's ataxia may offer a human model for the study of factors modulating cardiac hypertrophy. METHODS 55 patients (mean (SD) age 30 (9) years) with a clinical diagnosis of Friedreich's ataxia were studied by clinical examination, electrocardiography, cross sectional and Doppler echocardiography, and analysis of the GAA repeat in the first intron of the frataxin gene. RESULTS A wide variety of cardiac morphology was documented. Subjects with normal frataxin alleles had no evidence of cardiomyopathy. In homozygous subjects, a relation was found between the thickness of the interventricular septum (r = 0.53, p < 0.005), left ventricular mass (r = 0.48, p < 0.01), and the number of GAA repeats on the smaller allele of the frataxin gene. No relation was shown between the presence of electrocardiographic abnormalities (mainly repolarisation changes) and either the pattern of ventricular hypertrophy (if present) and degree of neurological disability or the length of time since diagnosis. No tendency to ventricular thinning or dilatation with age was found. Although ventricular systolic function appeared impaired in some cases, Doppler studies of ventricular filling were within the normal range for age. CONCLUSIONS The cardiomyopathy associated with Friedreich's ataxia shows a variable phenotype which is not concordant with the presence of ECG abnormalities or the neurological features of the condition. As the genetic basis for Friedreich's ataxia has been established, further studies will help to clarify the molecular mechanisms of the cardiac hypertrophy.
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Affiliation(s)
- D P Dutka
- National Heart and Lung Institute, Imperial College of Science, Technology and Medicine, Hammersmith Campus, Du Cane Road, London W12 0NN, UK.
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23
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Alday LE, Bruno E, Moreyra E, Amuchastegui LM, Juaneda E, Maisuls H. Mid-Term Results of Dual-Chamber Pacing in Children with Hypertrophic Obstructive Cardiomyopathy. Echocardiography 1998; 15:289-296. [PMID: 11175042 DOI: 10.1111/j.1540-8175.1998.tb00609.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND: Permanent dual-chambered pacing (DDD) is an alternative to surgical treatment in patients with severe hypertrophic obstructive cardiomyopathy (HOCM) who do not have a satisfactory response to medical treatment. METHODS: Five children with severe HOCM still symptomatic despite medical treatment underwent permanent DDD pacing and were followed for 21 +/- 9.7 months. RESULTS: All patients improved their functional class. Doppler echocardiographic studies showed an early reduction of the left ventricular outflow tract gradient from 66 +/- 40 to 40 +/- 20 mmHg (P < 0.05) and to 30 +/- 11 mmHg (P < 0.05 and NS for comparison with the baseline and the early post-DDD pacing gradients, respectively) at mid-term follow-up. There was no evidence of left ventricular systolic dysfunction, and the results of left ventricular filling studies ruled out deleterious effects on diastolic function. Doppler echocardiography played a key role in the initial and subsequent assessment of these patients. CONCLUSIONS: Permanent DDD pacing is a reasonable alternative to surgery in children with HOCM who are still symptomatic despite medical therapy.
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Affiliation(s)
- Luis E. Alday
- Section of Pediatric Cardiology, Hospital Privado, Naciones Unidas 346, 5016 Cordoba, Argentina
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24
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Runge MS, Stouffer GA, Sheahan RG, Lerakis S. Hypertrophic Cardiomyopathy: Presentation and Pathophysiology. Am J Med Sci 1997. [DOI: 10.1016/s0002-9629(15)40230-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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25
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Abstract
HCM is a heterogeneous disease with various clinical presentations. Recent advances in understanding the genetic abnormalities responsible for ventricular hypertrophy promise to improve our ability to diagnose this condition and to identify subgroups who are at the highest risk of cardiovascular mortality. Numerous difficulties remain in treating patients with HCM, including obtaining relief of symptoms and preventing SCD, but several new treatment options are currently being evaluated. In the future, randomized trials comparing the major treatment options (eg, pharmacologic therapy, myotomy/myectomy, mitral valve replacement, pacemaker implantation, and nonsurgical septal reduction) will be needed to provide guidance concerning the optimal treatment of patients with HCM.
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Affiliation(s)
- S Lerakis
- Department of Medicine, University of Texas Medical Branch, Galveston 77555-1064, USA
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26
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Fananapazir L, McAreavey D. Hypertrophic cardiomyopathy: evaluation and treatment of patients at high risk for sudden death. Pacing Clin Electrophysiol 1997; 20:478-501. [PMID: 9058851 DOI: 10.1111/j.1540-8159.1997.tb06206.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Hypertrophic cardiomyopathy (HCM) is a heritable disease characterized by LV hypertrophy with markedly variable clinical, morphological, and genetic manifestations. It is the most common cause of sudden death in otherwise healthy young individuals. HCM patients often have disabling symptoms and are prone to arrhythmias. Frequently, there is associated LV systolic and diastolic dysfunction, LV outflow obstruction, and myocardial ischemia. Over the past decade, progress has been made in identifying patients who are at high risk for sudden death, in elucidating potential mechanisms of sudden death, and in defining therapeutic algorithms that may improve prognosis. It has also been possible to determine the genetic defect in some of the patients and to correlate clinical findings with the molecular defects. An exciting development has been the use of dual chamber pacemaker as an alternative to cardiac surgery to improve symptoms and relieve LV outflow obstruction.
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MESH Headings
- Age Factors
- Cardiomyopathy, Hypertrophic/diagnosis
- Cardiomyopathy, Hypertrophic/etiology
- Cardiomyopathy, Hypertrophic/genetics
- Cardiomyopathy, Hypertrophic/therapy
- Death, Sudden, Cardiac/etiology
- Death, Sudden, Cardiac/prevention & control
- Electrophysiology/methods
- Humans
- Risk Assessment
- Syncope/diagnosis
- Syncope/etiology
- Tachycardia, Ventricular/diagnosis
- Tachycardia, Ventricular/etiology
- Tachycardia, Ventricular/therapy
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Affiliation(s)
- L Fananapazir
- Cardiology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892-1650 USA.
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27
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Palmiter KA, Solaro RJ. Molecular mechanisms regulating the myofilament response to Ca2+: implications of mutations causal for familial hypertrophic cardiomyopathy. Basic Res Cardiol 1997; 92 Suppl 1:63-74. [PMID: 9202846 DOI: 10.1007/bf00794070] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In this chapter we consider a current perception of the molecular mechanisms controlling myofilament activation with emphasis on alterations that may occur in familial hypertrophic cardiomyopathy (FHC). FHC is a sarcomeric disease (100) with an autosomal dominant pattern of heritability (27, 51). There is a substantial body of evidence implicating missense mutations in the beta-MHC gene as causal for the development of this disease. Recently, mutations in genes of two thin filament regulatory proteins, cardiac troponin T(cTnT) and alpha-tropomyosin (alpha-Tm), have also been linked to FHC. The commonality among the functional consequences of these mutations remains an important question. This review discusses how these pathological mutations may impact the activation process by disrupting critical structure function relations in both the thick and thin filaments.
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Affiliation(s)
- K A Palmiter
- Department of Physiology and Biophysics, University of Illinois at Chicago 60612, USA
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28
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Posma JL, van der Wall EE, Blanksma PK, van der Wall E, Lie KI. New diagnostic options in hypertrophic cardiomyopathy. Am Heart J 1996; 132:1031-41. [PMID: 8892780 DOI: 10.1016/s0002-8703(96)90018-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The pathophysiologic features and clinical manifestations of HCM have been elucidated by the introduction of several new diagnostic options. Knowledge of the molecular defects of HCM has advanced rapidly, and genetic screening studies have reemphasized the value of the standard electrocardiogram as an initial screening tool. Analysis of heart rate variability, late potentials, and QT dispersion were not found to be reliable prognostic markers in HCM. However, measurement of dispersion of conduction is probably a sensitive technique in identifying a high risk for sudden cardiac death. Significant developments include transthoracic and transesophageal echocardiography and their role in studying the mitral valve, early detection of left ventricular chamber dilatation, analysis of coronary flow, and intraoperative echocardiography. Finally, advances in the application of magnetic resonance imaging and positron-emission tomography are underway.
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Affiliation(s)
- J L Posma
- Department of Cardiology, Thoraxcenter, University Hospital Groningen, The Netherlands
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29
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Abstract
Mutations in several muscle structural proteins (the myosin heavy chain, alpha tropomyosin, cardiac troponin T and myosin binding protein C) result in a genetically dominant heart disease, hypertrophic cardiomyopathy. Biochemical data from studies of mutant myosin suggest a dominant-negative mechanism for inheritance of this disease. The most likely primary defect is sarcomere dysfunction, which is followed by the major clinical symptoms.
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Affiliation(s)
- K L Vikstrom
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder 80309-0347, USA.
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