Case 5

Stem: This healthy 56 year old man who is not on any medications suddenly lost consciousness without any warning while riding a bicycle. He fell off his bicycle, but has no recollection of the accident. He recovered consciousness immediately after the fall, with no headache or confusion or chest pain. His GCS was 15 and his vital signs were normal. There were no signs of head injury, but his right shoulder was tender and his spine was tender over the mid-thoracic and lower lumbar spine.

CAT scans of the head, cervical spine, thoracic spine and lumbar spine did not show any acute injury.

+ List the significant findings in the ECG

  • The ventricular rate is about 43 beats per minute
  • The QRS width is normal
  • The QT interval is normal (400 msec)
  • The QRS morphology is unusual in the limb leads and the praecordial leads
  • Frontal leads:
    • The frontal plane QRS axis is about +144 degrees i.e. there is marked right axis deviation
    • Leads I and aVL : an inverted P wave before each complex, QS morphology, (?) inverted T wave in Lead I, inverted T wave in Lead aVL
    • Leads II, III and aVF: Normal P-QRS-T morphology
    • Lead aVR: small amplitude upright QRS complex
    • The atrial rate is about 43 beats per minute. The PR interval is 0.24 sec i.e there is first degree heart block
    • The P wave axis is about +133 degrees i.e there is a markedly rightward P wave vector
  • Praecordial leads
    • There is negative concordance i.e. the complexes in Leads V1 to V6 are all predominately downward (rS in Leads V1 to V5, and QS in Lead V6)
    • The amplitude of the QRS complexes decreases as we go from Lead V1 to Lead V6
    • The P wave in Lead V1 is upright but has a low amplitude, the P wave in Leads V2 to V4 is biphasic, and the P wave in Leads V5 and V6 is inverted

+ Provide the most likely or important diagnosis

From the CT Image

  • (A). The cardiac apex and the the gastric bubble are on the patient's right side, and the hepatic outline is on the patient's left side
  • (B). The aortic arch is on the patient's right side
  • The patient has situs inversus and dextrocardia


  1. The patient's chest Xray and the QRS complexes located on the frontal plane hexaxial system are shown in Figure 3.
    Figure 3
  2. The ECG morphology in the V leads using standard chest lead placement and right sided chest leads is shown in Figure 4
    Figure 4
  3. A follow up Holter monitor tracing demonstrating non-sustained ventricular tachycardia is shown in Figure 5
    Figure 5