What is structural heart disease?

Structural Heart Disease: Definition and Clinical Implications

Structural heart disease refers to any abnormality of cardiac structure or function, including disorders of the pericardium, myocardium, endocardium, heart valves, or great vessels, but excluding primary valvular diseases. 1

Definition and Classification

• Structural heart disease (SHD) encompasses a broad spectrum of cardiac abnormalities affecting the structure and function of the heart beyond primary valvular diseases 1
• SHD includes disorders of the:
  • Pericardium (the protective sac surrounding the heart) 1
  • Myocardium (heart muscle tissue) 1
  • Endocardium (inner lining of the heart chambers) 1
  • Heart valves (when part of a broader structural abnormality) 1
  • Great vessels (aorta and pulmonary arteries) 1
• SHD is distinct from congenital heart disease (CHD), which specifically refers to structural cardiac abnormalities present before birth due to abnormal fetal cardiac development 2

Types of Structural Heart Disease

• Myocardial disorders:
  • Cardiomyopathies (dilated, hypertrophic, restrictive) 1
  • Left ventricular hypertrophy or fibrosis 1
  • Left ventricular dilatation or hypocontractility 1
• Valvular abnormalities:
  • Valvular stenosis or regurgitation (when part of a broader structural problem) 1
  • Bicuspid aortic valve disease 2
• Septal defects:
  • Atrial septal defects 2
  • Ventricular septal defects 3
  • Patent foramen ovale 2
• Other structural abnormalities:
  • Left atrial appendage abnormalities 2
  • Pericardial diseases 1

Clinical Significance and Staging

• SHD plays a crucial role in the development and progression of heart failure 2, 1
• The American College of Cardiology and American Heart Association classify heart failure in stages that incorporate structural heart disease 2, 1:
  • Stage A: Patients at risk for heart failure without structural heart disease 1
  • Stage B: Patients with structural heart disease but no symptoms of heart failure 1
  • Stage C: Patients with structural heart disease with current or prior symptoms of heart failure 1
  • Stage D: Patients with advanced structural heart disease and marked symptoms despite maximal medical therapy 1

Diagnostic Evaluation

• Echocardiography with Doppler flow studies is the most useful diagnostic test for evaluating structural heart disease 1, 4
• Additional imaging modalities include:
  • Cardiac MRI for tissue characterization and functional assessment 1
  • Cardiac CT for anatomical details and calcification 1
  • Nuclear imaging studies for perfusion and viability assessment 1
• Comprehensive evaluation includes assessment of:
  • Chamber size and function 4
  • Wall thickness and motion 4
  • Valve structure and function 4
  • Presence of abnormal communications between chambers 4

Clinical Implications and Management

• SHD increases the risk for heart failure progression 1
• SHD can produce heart failure and cardiogenic shock despite preserved systolic function 3
• Management approaches include:
  • Medical therapy (ACE inhibitors, beta-blockers) for stages B/C heart failure 1
  • Transcatheter interventions for specific structural abnormalities 5
  • Surgical repair or replacement for severe structural abnormalities 3
• The field of SHD intervention has evolved rapidly with minimally invasive approaches 5, 6:
  • Transcatheter aortic valve implantation (TAVI) 5
  • Transcatheter mitral valve repair 5
  • Left atrial appendage occlusion 6
  • Septal defect closure 2

Emerging Technologies in SHD Management

• 3D printing for procedural planning and physician training 7
• Computational modeling to understand fluid mechanics and device interactions 7
• Artificial intelligence applications for improved diagnosis and treatment planning 7
• Advanced imaging techniques for periprocedural guidance 7, 8