Images in Cardiovascular Medicine
Cannon Sounds
2018 Volume 82 Issue 10 Pages 2686-
Details
2018 Volume 82 Issue 10 Pages 2686-
A 61-year-old woman presented with a prolapse of the uterus. On examination, the pulse was 37 beats/min and electrocardiogram showed a third-degree atrioventricular block. Cardiology consultation was obtained. Auscultation showed varying intensities of the first sound (S1), followed by systolic ejection murmurs, as well as extra sounds with irregularity (Movie S1). The amplitude of S1 was often loud, as was the extra sound when it occurred after the second sound (S2). On phonocardiography, S1 was loudest in a short PR interval, known as the “cannon sound”. The extra sounds were detected after P waves and occurred in the lower frequency ranges, consistent with the fourth sound (S4); of note, the intensity of S4 was loudest when the extra sound occurred during early diastole or around 200 ms after S2 (Figure). The cannon sound, which was first described in 1908 by Huchard and recorded in 1929 by Selenin and Fogelson,1 is caused by ventricular contraction with wider separation of the atrioventricular valves and higher atrial pressure.2 Another loud extra sound can occur as a result of atrial contraction during ventricular rapid filling ― namely the atrial cannon sound ― probably due to the intense vibration of the ventricular walls.
Electrocardiogram showing complete dissociation between the P waves and QRS complexes. On phonocardiography, which was obtained at the apex in the half left lateral decubitus position, an increase in intensity of the first sound (S1) with a short PR interval (large arrowhead) was noted. After a P wave, an extra sound is present in the low (L) and lower-middle (M1) frequency ranges (arrows), with the intensity loudest during early diastole (small arrowhead). A systolic ejection murmur is recorded in the higher-middle (M2) and high frequency (H) ranges (asterisk). S2, second sound.
None.
Supplementary File 1
Movie S1. Heart sound.
Please find supplementary file(s);
http://dx.doi.org/10.1253/circj.CJ-18-0311
