A tricky case of partial anomalous pulmonary venous drainage
A 61-year-old man presented with recurrent presyncope, 12-lead ECG and echocardiographic features of a right ventricular (RV) cardiomyopathy, and non-sustained ventricular tachycardia on Holter monitoring. During defibrillator implant for presumed arrhythmogenic RV cardiomyopathy, ventricular pacing parameters were satisfactory and the following images were obtained. The implantable cardioverter defibrillator lead appeared well sited in the RV apex on posterior-anterior fluoroscopy.

However, screening in the left anterior oblique (LAO) projection raised doubts about the true lead position. On-table echocardiography and 12-lead ECG confirmed lead placement within the left ventricle (LV). Pullback of the lead, while screening, suggested passage to the systemic circulation via an atrial septal defect (video available). Attempts to reposition the lead by advancing it from the superior vena cava (SVC) revealed an anomalous connection to a right pulmonary vein.

The lead was eventually placed within the RV apex. Prior MRI imaging commented on the suspicion of a connection between the right and left heart, and possible ASD. The ventricular measurements were: RV ejection fraction (EF) of 48% (range 49%–73%), indexed RV end-diastolic volume (EDV) of 124 mL/m2 (range 67–111 mL/m2), indexed RV end-systolic volume (ESV) of 63 mL/m2 (range 20–48 mL/m2); LVEF of 55% (range 59%–83%), indexed LVEDV of 83 mL/m2 (range 53–97 mL/m2), indexed LVESV of 38 mL/m2 (range 10–34 mL/m2).

Subsequent CT with contrast confirmed the presence of partial anomalous pulmonary venous drainage of the right upper and middle pulmonary veins into the SVC and superior sinus venosus defect. This patient subsequently underwent successful surgical patch repair of his superior sinus venosus defect and baffling of the right upper and middle pulmonary veins to the left atrium.

Learning points
• This case reinforces the importance of accounting for possible intracardiac shunts with suspected RV cardiomyopathies and for detailed assessment of this during cardiac imaging. In addition, it highlights the relevance of screening in the LAO projection for RV apical lead positioning.

• It is important to adopt a meticulous approach during implantable cardioverter defibrillator (ICD) insertion and lead positioning should be confirmed using both posterior-anterior and left anterior oblique projections on fluoroscopy.

• If in doubt about the ICD lead position despite fluoroscopy, other methods should be employed such as 12-lead ECG and on-table echocardiography.

• Remember to assess for possible intracardiac shunts in patients who present with suspected right ventricular cardiomyopathies, including detailed assessment of any prior cardiac imaging.

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