Ventricular Septal Defect

Ventricular Septal Defect 2018-01-30T16:37:47+08:00

Relevant physical signs

  • Inspection
    • Syndromic facies (Down’s syndrome)
    • Central cyanosis
  • Peripheries
    • Clubbing
    • Peripheral cyanosis
    • Stigmata of infective endocarditis
    • Pulse rate and rhythm
    • Central cyanosis
    • Jugular venous pulsation – raised / giant V waves
  • Chest
    • Inspection – scars to suggest previous surgery
    • Palpation
      • Apex beat – may be displaced with chronic left ventricular overload
      • Parasternal heave
      • Palpable thrill
    • Auscultation
      • Pan-systolic murmur loudest over the lower left sternal edge
      • Loud P2 to indicate pulmonary hypertension
      • Associated murmurs
        • Early diastolic murmur (aortic regurgitation, peri-membranous defects)
  • Complications
    • Pulmonary oedema – left ventricular failure
    • Raised jugular venous pulsation, right ventricular heave, loud P2 – pulmonary hypertension
    • Cyanosis, clubbing – Eisenmenger’s syndrome
    • Janeway lesions, Osler nodes, splinter haemorrhages – infective endocarditis
    • Tachycardia – ventricular tachyarrhythmias

Differential diagnosis

  • Ventricular septal defect
  • Mitral regurgitation – murmur loudest at apex, radiates to axilla, soft S1
  • Tricuspid regurgitation – murmur loudest at LLSE on inspiration, giant V waves, pulsatile liver

Causes of a VSD

  • Congenital
    • Infundibular (supracristal) VSD – defect in the septum above and anterior to the crista supraventricularis. Causes aortic cusp prolapse into VSD and progressive aortic regurgitation
    • Membranous VSD – defect in membranous septum
      • Perimembranous VSD – defect extending into muscular septum
    • Inlet defect, associated with Down’s syndrome
    • Muscular defect
    • Gerbode defect – left ventricular to right atrial shunt
    • Tetralogy of Fallot
      • Pulmonary stenosis
      • Overriding aorta
      • Ventricular septal defect
      • Right ventricular hypertrophy
  • Acquired
    • Post-myocardial infarction
    • Post-cardiac surgery

Clinical markers of haemodynamic significance

  • Insignificant
    • Pan-systolic murmur, often very loud, heard all over precordium
  • Significant, left to right shunt
    • Pan-systolic murmur, may be softer
    • Displaced apex beat
    • Systolic thrill
    • Parasternal heave
    • Loud P2
  • Significant, right to left shunt
    • Clubbing
    • Cyanosis
    • Irregular pulse
    • Parasternal heave
    • Loud P2
    • Pan-systolic murmur of functional tricuspid regurgitation
    • PSM of VSD is often inaudible in such shunts because of equalization of LV and RV pressures

Investigation

  • Chest radiograph
    • Cardiomegaly
    • Pulmonary oedema
    • Dilated pulmonary arteries (pulmonary hypertension)
  • Electrocardiogram
    • Left ventricular hypertrophy (LV volume overload)
    • Dominant R waves in V1 (RVH)
  • Trans-thoracic echocardiogram
    • Location, size and direction of shunt
    • Look for pulmonary hypertension
    • Assess left ventricular dimensions and function

Management

  • Multidisciplinary team approach, patient education
  • Medical
    • No need for infective endocarditis prophylaxis (unless cyanotic)
    • Treat acute episodes of congestive cardiac failure
  • Indications for closure (percutaneous or surgical)
    • Recurrent infective endocarditis
    • Development of aortic regurgitation
    • Left ventricular dilation / dysfunction
    • Reversible pulmonary hypertension / RV pressures > 50mmHg
    • Acute VSD complicating myocardial infarction
  • Contraindications: irreversible pulmonary hypertension / Eisenmenger’s syndrome

Summary

Sir, this patient has a ventricular septal defect with a haemodynamically-significant left-to-right shunt. On examination of the peripheries, there are no stigmata of infective endocarditis. There is no cyanosis, and the patient is not clubbed. The pulse is regular. On examination of the precordium, the apex beat is displaced inferolaterally. There is a pan-systolic murmur heard loudest over the lower left sternal edge in expiration. There is no evidence of co-existent aortic regurgitation. There are no clinical signs of pulmonary hypertension, such as a loud P2 or a right ventricular heave. Causes of a VSD may be congenital or acquired.

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