Desislava Zamfirova, Mihail Boyanov, Stefan Naydenov
Background/Objectives: Primary hyperparathyroidism (PHPT) has been associated with cardiovascular abnormalities, but the extent to which these reflect PHPT or conventional risk factors remains uncertain. We compared cardiovascular risk profiles and cardiac findings in patients with PHPT and controls. Methods: In this single-center cross-sectional case-control study, 5868 hospitalized patients were screened between January 2024 and December 2025. Fifty-four patients with biochemically confirmed PHPT and 23 age- and sex-comparable controls underwent standardized clinical, laboratory, 12-lead electrocardiogram (ECG), 24-h Holter ECG, and transthoracic echocardiographic assessment. Results: Patients with PHPT had higher systolic blood pressure (132.5 vs. 130.0 mmHg; p = 0.049), more type 2 diabetes (18.5% vs. 0%; p = 0.028), left ventricular hypertrophy (57.4% vs. 30.4%; p = 0.046), longer transmitral flow deceleration time (281.5 vs. 222.0 ms; p < 0.001), higher pulmonary artery systolic pressure (PASP) (24.5 vs. 19.0 mmHg; p < 0.001), and more aortic valve sclerosis/fibrotic thickening (38.9% vs. 13.0%; p = 0.032). High/very high cardiovascular risk was present in 54/54 (100%) PHPT patients versus 20/23 (86.96%) controls (p = 0.024). After adjustment, PHPT remained associated with longer deceleration time, higher PASP, aortic valve sclerosis/fibrotic thickening, and pericardial effusion. Conclusions: PHPT was associated with selected echocardiographic abnormalities, but causality cannot be inferred. Larger prospective studies are needed.