Characterisation of hypertensive heart disease: pathological insights from a sudden cardiac death cohort to inform clinical practice.

Hypertensive heart disease refers to changes in the myocardium that result from hypertension. The relationship between hypertensive heart disease and sudden cardiac death is well established, but there are few pathological studies. We examined the clinical and pathological features of hypertensive heart disease in sudden cardiac death victims from a national cardiovascular pathology registry. We investigated 5239 cases of sudden cardiac death between 1994 and 2018. Hearts were examined by two expert cardiac pathologists. Diagnostic criteria included history of hypertension, increased heart weight and left ventricular wall thickness in the absence of other causes. Collagen was quantified using picrosirius red staining and imaging software. Of 75 sudden cardiac death cases due to hypertensive heart disease (age at death: 54 ± 16 years; 56% males), 56 (75%) reported no prior cardiac symptoms. Thirty-four (45%) recorded a BMI ≥ 30. Only two (2.7%) had hypertensive heart disease diagnosed antemortem. Four (5%) were diagnosed clinically with hypertrophic cardiomyopathy, but lacked myocyte disarray at autopsy. All hearts showed concentric left ventricular hypertrophy and myocyte hypertrophy. Fibrosis was identified microscopically in 59 cases (81%). The posterior left ventricular wall showed the greatest increase in the percentage of collagen in hypertensive diseased hearts compared to controls (25.2% vs 17.9%, p = 0.034). Most sudden deaths due to hypertensive heart disease occur without prior cardiac symptoms; thus, clinical risk stratification is challenging. Hypertensive heart disease can be misdiagnosed in life as hypertrophic cardiomyopathy which has major implications for relatives. Pathologists require a history of hypertension and histology for a definitive diagnosis of hypertensive heart disease.