Severe infundibular pulmonary stenosis and coronary artery stenosis with ventricular tachycardia 24 years after mediastinal irradiation

Right Ventricular Outflow Tract Obstruction in Adults: A Systematic Review and Meta-analysis

Background

Right ventricular outflow tract obstruction (RVOTO) is a cause of hemodynamic instability that can occur in several situations, including cardiac surgery, lung transplantation, and thoracic surgery, and in critically ill patients. The timely diagnosis of RVOTO is important because it requires specific considerations, including the adverse effects of positive inotropes, and depending on the etiology, the requirement for urgent surgical intervention.

Methods

The objective of this systematic review and meta-analysis was to determine the prevalence of RVOTO in adult patients, and the distribution of all reported cases by etiology.

Results

Of 233 available reports, there were 229 case reports or series, and 4 retrospective cohort studies, with one study also reporting a prospective cohort. Of 291 reported cases of RVOTO, 61 (21%) were congenital, 56 (19%) were iatrogenic, and 174 (60%) were neither congenital nor iatrogenic (including intracardiac tumour). The mechanism of RVOTO was an intrinsic obstruction in 169 cases (58%), and an extrinsic obstruction in 122 cases (42%). A mechanical obstruction causing RVOTO was present in 262 cases (90%), and 29 cases of dynamic RVOTO (10%) were reported. In the 5 included cohorts, with a total of 1122 patients, the overall prevalence was estimated to be 4.0% (1%-9%).

Conclusions

RVOTO, though rare, remains clinically important, and therefore, multicentre studies are warranted to better understand the prevalence, causes, and consequences of RVOTO.

Recurrent syncope 20 years after mediastinal radiation therapy in a patient with breast cancer

Mediastinal radiation therapy can cause progressive fibrosis and might, as a result, induce various cardiac problems. We encountered a patient who presented with recurrent syncope 20 years after radiation therapy for breast cancer. She had multiple cardiac problems including bilateral coronary ostial stenoses, pre-valvular right ventricular outflow tract stenosis, and constrictive pericarditis. The cause of syncope was paroxysmal atrioventricular block (an 18-s long pause recorded by the implantable loop recorder). The patient was treated by the implantation of a pacemaker and did not experience syncope during 9 months of follow up.