Clicks are extra, brief, high-frequency heart sounds that can be auscultated during systole or diastole. They are typically classified based on timing:

• Ejection clicks: Occur shortly after the first heart sound (S1), usually associated with forceful opening of the aortic or pulmonic valves or sudden distention of a dilated aorta or pulmonary artery.

• Systolic clicks: Occur in mid-to-late systole, most often associated with mitral valve prolapse. They are heard most distinctly at or medial to the apex, but may also be detected at the lower left sternal border.

Clicks provide important diagnostic clues for valvular and congenital heart disease.

Pathophysiology

• Ejection clicks: Result from abrupt tension on the valve leaflets or vessel walls during early systolic ejection. Common causes include:

  • Pulmonary hypertension or increased pulmonary vascular resistance

  • Septal defects (e.g., atrial or ventricular septal defects)

  • Patent ductus arteriosus

• Systolic clicks: Arise from sudden tensing of the mitral valve apparatus during systolic prolapse. Often associated with myxomatous degeneration of the mitral valve leaflets.

These clicks reflect altered hemodynamics and mechanical stress on cardiac structures, providing valuable insight into underlying cardiac pathology.

Examination technique

Patient Positioning

• For ejection clicks: Have the patient sit upright or supine.

• For systolic clicks: Supine or left lateral decubitus position enhances auscultation.

Auscultation

• Use the diaphragm of the stethoscope for high-frequency sounds.

• Ejection clicks: Listen over the upper sternal borders, particularly the pulmonic and aortic areas.

• Systolic clicks: Listen at or medial to the apex; can also be heard at the lower left sternal border.

• Timing assessment: Note whether the click occurs early systole (ejection) or mid-to-late systole (mitral prolapse).

Clinical Utility

• Diagnostic indicator: Supports the presence of valvular disease or congenital cardiac anomalies.

• Monitoring and follow-up: Detection of new clicks may indicate progression or change in valve function.

• Adjunct to echocardiography: Clicks may prompt echocardiographic evaluation for structural abnormalities.

Differential Diagnosis

Pediatric considerations

• Ejection clicks are common in children with congenital heart disease.

• Innocent clicks may be present in healthy adolescents, requiring differentiation from pathological clicks.

Geriatric considerations

• Systolic clicks in older adults may indicate mitral valve degeneration or prolapse.

• Ejection clicks may reflect age-related changes in aortic or pulmonary valve rigidity.

Limitations

• Clicks may be subtle and easily missed without careful auscultation.

• Positioning and maneuvers significantly affect audibility.

• Must be interpreted alongside other findings: murmurs, ECG, imaging.

Patient counseling

• Explain that clicks are non-painful sounds detected during cardiac evaluation.

• Emphasize that detection often prompts further assessment, such as echocardiography.

• Reassure patients that some clicks may be innocent or benign, particularly in children and young adults.

Conclusion

Clicks are high-frequency heart sounds that provide valuable clues to valvular and congenital cardiac disorders. Correct identification, timing, and correlation with clinical features enhance diagnostic accuracy, guide further evaluation, and support appropriate management.

References

1. Braunwald E. Braunwald’s Heart Disease: A Textbook of Cardiovascular Medicine. 12th ed. Philadelphia: Elsevier; 2022.

2. McPhee SJ, Papadakis MA. Current Medical Diagnosis and Treatment 2023. New York: McGraw-Hill; 2023.

3. Carabello BA, Crawford MH. Cardiac Auscultation and Heart Sounds. Circulation. 1997;95:2112–2120.

4. Otto CM. Textbook of Clinical Echocardiography. 5th ed. Philadelphia: Elsevier; 2021.

5. American Heart Association. Evaluation of Heart Murmurs and Extra Heart Sounds. Circulation. 2021;144:e522–e536.