Cardiac CT for electrophysiological interventions

Abstract

Cardiac computed tomography (CCT) holds an important role in the field of electrophysiology offering critical insights that enhance the management of arrhythmias through precise procedural planning and execution. It has furthermore established its role as a useful imaging modality in left atrial appendage closure procedures. This review discusses the current applications of CCT from pre-interventional assessment to post-interventional follow-up, emphasizing its utility in improving the safety and efficacy of electrophysiological and left atrial appendage occlusion interventions. It also explores the integration of CCT with advanced technologies such as electroanatomical mapping systems and the emergence of innovative imaging modalities, including three-dimensional cardiac computational modelling. CCT's evolving capabilities suggest a promising future in electrophysiology and left atrial occlusion procedures when combined with further technological advancements, including artificial intelligence software.

Keywords: AI; Atrial fibrilation; CCT; Electrophysiology; LAAO.

Fig. 1

Assessment of LAA using CCT using arterial (left panels) and delayed phase imaging (right panels) in patients with atrial fibrillation planned for pulmonary vein isolation. Upper left panels depicts a representative example of a LAA free of thrombus, evident by the normal contrast enhancement in both phases. Upper right panels demonstrate an example of slow-flow phenomenon in a patient with severely dilated left atrium. Inhomogeneity and lack of contrast enhancement of the distal part of LAA in the arterial phase, which does not persist in the delayed imaging phase, where the LAA is homogenously contrasted. Lower panels depict an LAA thrombus (thrombus in transit) with a filling defect at the proximal part of the LAA in the arterial phase, which persists in the delayed imaging phase. LAA, left atrial appendage, CCT; cardiac computed tomography

Fig. 2

Anatomy of the LA and PVs at CCT using the axial images and 3D reconstruction. The most common configuration features four distinct PV ostia in the posterior LA on the right, the right superior and inferior PVs (RSPV and RIPV) have separate ostia, often divided by the LA wall, while on the left, the superior and inferior PVs (LSPV and LIPV) typically share closely positioned ostia without such separation. An accessory PV draining separately into the LA from the ipsilateral superior and inferior PV creates additional ostia. These accessory PV, often named based on the pulmonary segment they drain, are more commonly found on the right side than on the left, with an incidence reported in up to one-fourth of the population. When present, accessory PV trunks are typically shorter and narrower than the main PVs and may sometimes cross pulmonary fissures. LA; left atrium, PV; pulmonic vein, CCT; cardiac computed tomography, 3D; three-dimensional, LAA; left atrial appendage

Fig. 3

Post LAAO assessment using CCT. Upper panel depicts an Amplatzer Amulet 31 mm occluder device with completely thrombosed LAA, evident by the lack of perfusion in the arterial and delayed imaging phase (from left to right). Lower panel depicts a Watchman FLX 24 mm occluder device with rest perfusion (asterisk) of the only partially thrombosed LAA, in both the arterial and delayed imaging phase (from left to right). LAAO; left atrial appendage occlusion, LAA; left atrial appendage, CCT cardiac computed tomography

Fig. 4

Use of CCT in the context of VT ablation. A 55-years old patient with ischemic cardiomyopathy and history of extensive myocardial infarction underwent a CCT for exclusion of LV thrombus in the LV. Upper panel demonstrates three chamber, two chamber and short axis CCT contrast enhanced images of the LV. Lower panel depicts the delayed phase imaging whereby a thrombus can be safely excluded based on the homogenous enhancement of the severely calcified, akinetic regions of the LV apex, the anterior and anteroseptal LV myocardium. The same contrast-enhanced CCT images were utilized peri-interventionally to guide the ablation procedure. LV; left ventricle, CCT; cardiac computed tomography, VT; ventricular tachycardia

Fig. 5

CCT for CIED assessment. A 63-years old woman with a history of dual chamber pacemaker implantation due to sick sinus syndrome, 10 years priorly and a revision one year ago due to pneumothorax, was presented with a few days history of diaphragm and thoracic muscle stimulation. Clinical examination and electrocardiogram were unremarkable. Transthoracic echocardiogram revealed a normal systolic function of the right and the left ventricle, yet raised the suspicion of presence of the right ventricle pacemaker electrode outside of the pericardium, with minimal fluid collection (Panel A). CCT further enhanced the suspicion of perforation of the right ventricular myocardium that was confirmed with three-dimensional reconstruction of the cardiac muscles, the pacemaker leads and the thoracic bone structures (Panel B and Panel C). The right ventricle electrode was completely removed and a new pacemaker implanted. CIED; cardiac implantable electronic device, CCT; cardiac computed tomography