Regular cannon wave

Abstract

A 52-year-old male with history of dilated cardiomyopathy was admitted with progressive dizziness and worsening dyspnea. His blood pressure was 100/60 with a regular pulse of 70 per minute. Jugular vein wave showed a prominent pulse like regular cannon waves. Cannon wave occurs in conditions with atrioventricular dissociation and right atrial contraction against a closed tricuspid valve. Large A waves are associated with reduced right ventricular compliance or elevated right ventricular end-diastolic pressure.

Keywords: Cannon waves; Junctional rhythm; ‘a’ reversal.

Fig. 1

Giant A wave in JVP indicated by arrow.

Fig. 2

Panel A: ECG showing junctional rhythm, LBBB, and long QTc interval. Panel B: Repeat ECG showing normal sinus rhythm with LBBB.

Fig. 3

Pulmonary venous Doppler showing prominent ‘a’ reversal.