Hypertrophic Cardiomyopathy: Treatment, Risk Stratification, and Implantable Defibrillators
Hypertrophic cardiomyopathy (HCM) affects 1:500 individuals, and in majority of cases, a mutation in sarcomere proteins can explain the disease. Phenotype is heterogeneous and thus the prognosis. Many patients suffer from dyspnoea, especially at exercise. Unfortunately, sudden cardiac death (SCD) does occur at all ages and is a major cause of death in young adults. There is no proven pharmacological treatment to reduce hypertrophy or fibrosis, but beta-blockers are first-line treatment. In patients with obstruction, myectomy is preferred in the young, but in older patients, alcohol septal ablation is tried to reduce symptoms and possibly prognosis. Risk stratification of sudden cardiac death is challenging. The major established risk factors are extreme myocardial thickness, non-sustained ventricular tachycardia, unexplained syncope, abnormal exercise blood pressure response, and family history of sudden cardiac death. In 2014, a novel risk calculator was developed that also takes age, outflow gradient, and left atrial seize into account. Implantable defibrillator treatment is effective in HCM, but complications requiring surgery and inappropriate shocks remain a problem.
Part of the book: Cardiomyopathies
Ischemic Cardiomyopathy: Contemporary Clinical Management
Ischemic cardiomyopathy, disease of the heart muscle due to coronary artery disease, is the most common cardiomyopathy. It is often difficult to discern the etiology of heart failure, and often there are multiple underlying causes. Ischemic cardiomyopathy most often presents with a dilated morphology with wall motion defects and a history of previous myocardial infarction or confirmed coronary artery disease. Mechanisms of myocardial depression in ischemia are necrosis of myocardial cells resulting in irreversible loss of function or reversible damage, either short term through myocardial stunning or long term through hibernation. In ischemic cardiomyopathy, echocardiography may be extended with stress testing or other imaging modalities such as myocardial scintigraphy and cardiac magnetic resonance tomography. Coronary angiography is often considered a gold standard; however, other modalities such as positron emission tomography can be needed to detect small vessel disease. Cardiac revascularization, through percutaneous coronary intervention and coronary artery bypass grafting, both in acute coronary syndrome and in stable coronary artery disease, relieves symptoms and improves prognosis. Therapy should aspire to treat ischemia, arrhythmias in addition to heart failure management, which includes device therapy with cardiac resynchronization therapy, implantable cardioverter defibrillators, and mechanical support as bridging or destination therapy in end-stage disease.
Part of the book: Current Perspectives on Cardiomyopathies
Cardiac Implantable Electronic Device-Related Infections
The use of cardiac devices, that is, pacemakers and implantable cardioverter defibrillators, has increased, and the incidence will likely continue to increase due to an aging population with associated risk factors. Unfortunately, this implies an increasing number of complications, including infections. Cardiac device-related infection is a dreaded complication causing both increased morbidity and mortality, and considerable costs. Because of the presence of a foreign body in subcutaneous tissue, vasculature, and the heart, patients with cardiac device systems are at increased risk of endocarditis due to microbial agents. In general, an infected device system should be removed in its entirety. The timing of reimplantation varies due to indication and severity of the infection. Furthermore, the explant procedure may be complicated and should be performed by an experienced team including facilities to handle life-threatening complications. The subcutaneous implantable cardioverter defibrillator or leadless pacemaker can serve as an option in selected cases. This chapter will describe clinical aspects of cardiac device-related infections.
Part of the book: Infective Endocarditis
Anticoagulation in Atrial Fibrillation Patients
Atrial fibrillation (AF) is the most common arrhythmia and may cause thromboembolic events, typically stroke. Advances in pharmacological approaches to anticoagulation and groundbreaking large randomized controlled trials of non-vitamin K antagonist oral anticoagulants (NOACs) have changed the paradigm of anticoagulation therapy. Furthermore, observational studies support the efficacy and safety of NOAC. Few studies address the differences among NOACs, but prescriptions should be based on a thorough understanding of their pharmacological differences, including interactions, side effects, reversibility, and practical approach. In a subset of patients with AF, warfarin may still be the preferable option. Consequently, an individualized approach to oral anticoagulation is crucial.
Part of the book: Epidemiology and Treatment of Atrial Fibrillation
The Wearable Cardioverter-Defibrillator
The wearable cardioverter-defibrillator (WCD) is a rechargeable external device that can be worn under the clothing all day long and protects the wearer from potentially life-threatening ventricular tachyarrhythmias. When a dangerous arrhythmia is detected, the WCD can deliver high-energy shocks. The WCD has been shown to be effective in accurately detecting and appropriately treating ventricular tachycardia (VT) and ventricular fibrillation (VF). It is intended for temporary use as a bridge to an implantable cardioverter-defibrillator (ICD), heart transplantation, or left ventricular assist device; patients with heart failure with reduced ejection fraction may benefit from the WCD while their condition improves. It can be used temporarily after explant of an ICD until reimplantation is deemed possible. In select patients with myocardial infarction, a WCD may be useful during the immediate period after infarction. It is indicated for use when a permanently implanted ICD must be explanted because of infection; the patient can use the WCD until the infection resolves, and a new ICD can be implanted. The role of the WCD is emerging as an important therapeutic option to protect patients at elevated risk of sudden cardiac death (SCD).
Part of the book: Sudden Cardiac Death
Familial Dilated Cardiomyopathy: Risk Stratification for Sudden Cardiac DeathView all chapters
Heart failure implies a considerable burden for patients and resources for the health care system. Dilated cardiomyopathy is defined as left ventricular dilation and reduced systolic function, not solely explained by ischemic heart disease or abnormal loading conditions. Numerous genes have been identified in familial cases of dilated cardiomyopathy. Heart failure with reduced ejection fraction increases the risk for sudden cardiac death. Implantable cardioverter defibrillator therapy can provide a means of preventing sudden cardiac death in those deemed to be at high risk. Health care providers are in need of better tools in order to improve risk stratification. This chapter aims to provide an overview of the current knowledge about risk of arrhythmia and sudden death in patients with familial dilated cardiomyopathy, in particular for those patients with a specific mutation.
Part of the book: Sudden Cardiac Death