11/09/2024
𝐔𝐧𝐝𝐞𝐫𝐬𝐭𝐚𝐧𝐝𝐢𝐧𝐠 𝐜𝐥𝐨𝐜𝐤𝐰𝐢𝐬𝐞 𝐫𝐨𝐭𝐚𝐭𝐢𝐨𝐧
The term “clockwise rotation” describes the apparent rotation of the heart as viewed from below in standard CT/MRI cross-sectional imaging views. High pulmonary pressures in PE cause acute RV pressure overload and dilatation, compressing the interventricular septum (IVS). Ensuing RV dysfunction and hypokinesis worsens these changes, particularly in the apical region. Leads V5-6, which usually face the LV wall and reflect LV depolarisation directly, are subsequently orientated over the IVS. The R/S transition point thus shifts rightwards towards V6.
Image:
Left: Normal cross-sectional configuration of RV/LV
Right: RV dilatation and hypertrophy compressing the LV, creating “clockwise” rotation of the heart