Unilateral absence of pulmonary artery is a rare developmental anomaly. Infrahepatic inferior vena cava interruption is a well-recognized but uncommon developmental anomaly. Presence of both these anomalies in a single individual is extremely rare. A 58-year-old man with a history of recurrent lower extremity deep vein thrombosis and venous insufficiency presented to our emergency department with bilateral calf pain and swelling. Ultrasound demonstrated extensive deep vein thrombosis throughout bilateral lower extremities. Computed tomography angiography showed smooth tapering of the right pulmonary artery with absent distal most segment. To our knowledge, there is only 1 case report in the literature so far with both the abnormalities present in a single individual.

Background

The incidence of myocardial inflammation in patients with unexplained cardiomyopathy referred for ventricular arrhythmias (VAs) is unknown.

Objective

The purpose of this study was to report fasting positron emission tomographic (PET) scan findings in consecutive patients referred with unexplained cardiomyopathy and VA.

Methods

Fluorine-18 fluoro-2-deoxyglucose (18-FDG) PET/computed tomographic (CT) scans with a >16-hour fasting protocol were prospectively ordered for patients referred for VA and unexplained cardiomyopathy (ejection fraction <55%). Patients with focal myocardial FDG uptake were labeled as arrhythmogenic inflammatory cardiomyopathy (AIC) and classified into 4 groups based on the presence of lymph node uptake (AIC+) and perfusion abnormalities (early vs late stage).

Results

Over a 3-year period, 103 PET scans were performed, with 49% (AIC+ 17, AIC 33) exhibiting focal FDG uptake. Mean patient age was 52 ± 12 years (ejection fraction 36% ± 16%). Patients with AIC were more likely to have a history of pacemaker (32% vs 6%, P = .002) compared to those with normal PET. When biopsy was performed, histologic diagnosis revealed nongranulomatous inflammation in 6 patients and sarcoidosis in 18 patients. Ninety percent of patients with AIC/AIC+ were prescribed immunosuppressive therapy, and 58% underwent ablation. Correlation between low voltage regions on electroanatomic mapping and FDG uptake was observed in 74%. Magnetic resonance imaging findings matched abnormal PET regions in only 40%.

Conclusion

Nearly 50% of patients referred with unexplained cardiomyopathy and VA demonstrate ongoing focal myocardial inflammation on FDG PET. These data suggest that a significant proportion of patients labeled "idiopathic" may have occult AIC, which may benefit from early detection and immunosuppressive medical therapy.