Transiently elevated estimated pulmonary pressures in a patient with complete heart block undergoing permanent pacing: a case report

BACKGROUND: Complete heart block (CHB) is a frequent cause for acute admission in older patients with significant cardiac conduction disease. Common presenting symptoms are syncope and dyspnoea. Some patients may exhibit clinical and radiological signs of left ventricular (LV) decompensation, despite preserved LV ejection fraction on transthoracic echocardiography (TTE) and absent pre-existing LV dysfunction. CASE SUMMARY: In this clinical report, we present a case of CHB associated with transient but severe elevation in pulmonary artery systolic pressure, measured as the equivalent right ventricular systolic pressure (RVSP = 99 mmHg) by TTE in the absence of right ventricular outflow tract obstruction, that subsequently 'normalized' after implantation of a permanent pacemaker. After searching our echocardiogram database, we did find other cases with similar findings. DISCUSSION: There is limited literature describing transient acute elevation in estimated pulmonary pressures in the setting of new CHB that is subsequently reversed by permanent pacing. The true prevalence and mechanism of transient estimated pulmonary pressure as a result of CHB remains unknown. Based on our limited assessment, we postulate that the acute elevation in estimated pulmonary pressures is predominantly related to a compensatory augmentation of RV stroke volume and is caused by the underlying bradycardia and need to maintain forward cardiac output. This phenomenon may require further investigation and validation in future studies.