Radiation Heart Disease

KEY FEATURES

ESSENTIALS OF DIAGNOSIS

• History of mediastinal radiation therapy, usually for Hodgkin’s disease or left breast cancer

• Pericarditis early or within 10 years after radiation therapy

• Cardiomyopathy, especially if also treated with anthracyclines

• Coronary artery disease after a 15- to 20-year latency period

• Valvular regurgitation; occasionally stenosis

• Heart block; occasionally tachyarrhythmias

GENERAL CONSIDERATIONS

• Radiation cardiac injury is a broad spectrum that includes direct effects, indirect effects (lung irradiation), and augmentation of the effects of chemotherapy, such as with anthracyclines

• The initial injury is characterized by micro- and macrovascular inflammation, which subsides and transitions to a latent phase of progressively increasing fibrosis from ischemia until clinical disease is evident in the late stage

• Macrovascular disease is enhanced by the patient’s risk profile (eg, elevated low-density lipoprotein cholesterol)

• Radiation injury can involve any cardiac structure

• The incidence of cardiac injury with anterior mediastinum radiation therapy has been estimated to be up to 30% over 10 years

• Newer radiation therapy techniques have lowered this incidence

CLINICAL PRESENTATION

SYMPTOMS AND SIGNS

• Pericarditis: pleuritic chest pain, dyspnea

• Cardiomyopathy: dyspnea, fatigue

• Coronary artery disease: angina pectoris, dyspnea

• Valve disease: dyspnea

• Conduction disease: syncope, fatigue, palpitations

PHYSICAL EXAM FINDINGS

• Pericarditis: friction rub, jugular venous distention

• Cardiomyopathy: signs of heart failure

• Valve disease: predominantly mitral regurgitation and mixed aortic valve disease

DIFFERENTIAL DIAGNOSIS

• Pericarditis from other causes, especially hypothyroidism (thyroid in field)

• Cardiomyopathy from other causes, especially anthracyclines

• Coronary artery disease from other causes

• Valvular heart disease from other causes

• Cardiac arrhythmias from other causes

DIAGNOSTIC EVALUATION

LABORATORY TESTS

• Thyroid function

• Lipid panel

ELECTROCARDIOGRAPHY

• ST-T–wave changes of acute ischemia or pericarditis

• Q waves of myocardial infarction

• Chamber hypertrophy

• Conduction abnormalities

IMAGING STUDIES

• Chest x-ray: may show cardiomegaly

• Echocardiography: to assess pericardial effusion, myocardial function, and valve pathology

DIAGNOSTIC PROCEDURES

• Ambulatory ECG monitoring to detect arrhythmias

• Exercise or pharmacologic stress testing with echocardiography preferred to detect coronary artery disease

  • – Myocardial perfusion imaging may be falsely positive due to radiation fibrosis

• Coronary angiography and cardiac hemodynamic study may be necessary

TREATMENT

CARDIOLOGY REFERRAL

• Suspected cardiac disease

• Syncope

HOSPITALIZATION CRITERIA

• Heart failure

• Acute coronary syndromes

• Significant rhythm disturbances

MEDICATIONS

• Pharmacologic therapy for pericarditis, heart failure, arrhythmias, valve disease, and coronary artery disease as appropriate

THERAPEUTIC PROCEDURES

• Coronary artery disease: angioplasty is less successful than bypass surgery

• Heart block: A-V sequential pacing is recommended because the ventricles are often stiff