Cor bovinum or cor bovis refers to a massive hypertrophy of the left ventricle of the heart due to volume overload, usually in earlier times in the context of tertiary syphilis but currently more often due to chronic aortic regurgitation, hypertensive and ischaemic heart disease.
Due to syphilitic aortitis (a complication of tertiary syphilis) the aortic valve ring becomes dilated.
"In 93% of all patients with CB, we found coronary atherosclerosis as a sign of high blood pressure and in 79% a COPD."
High blood pressure, COPD and male sex were the main risk factors.
The decreasing incidence was ascribed to improved medical management: they mention treatments for high blood pressure and coronary artery disease, which suggests that "COPD" in their abstract refers to the latter.