Accessory left atrial diverticulae: contractile properties depicted with 64-slice cine-cardiac CT

Abstract

To assess the contractility of accessory left atrial appendages (LAAs) using multiphasic cardiac CT. We retrospectively analyzed the presence, location, size and contractile properties of accessory LAAs using multiphasic cardiac 64-slice CT in 102 consecutive patients (63 males, 39 females, mean age 57). Multiplanar reformats were used to create image planes in axial oblique, sagittal oblique and coronal oblique planes. For all appendages with an orifice diameter >or= 10 mm, axial and sagittal diameters and appendage volumes were recorded in atrial diastole and systole. Regression analysis was performed to assess which imaging appearances best predicted accessory appendage contractility. Twenty-three (23%) patients demonstrated an accessory LAA, all identified along the anterior LA wall. Dimensions for axial oblique (AOD) and sagittal oblique (SOD) diameters and sagittal oblique length (SOL) were 6.3-19, 3.4-20 and 5-21 mm, respectively. All appendages (>or=10 mm) demonstrated significant contraction during atrial systole (greatest diameter reduction was AOD [3.8 mm, 27%]). Significant correlations were noted between AOD-contraction and AOD (R = 0.57, P < 0.05) and SOD-contraction and AOD, SOD and SOL (R = 0.6, P < 0.05). Mean diverticulum volume in atrial diastole was 468.4 +/- 493 mm(3) and in systole was 171.2 +/- 122 mm(3), indicating a mean change in volume of 297.2 +/- 390 mm(3), P < 0.0001. Stepwise multiple regression analysis revealed SOL to be the strongest independent predictor of appendage contractility (R(2) = 0.86, P < 0.0001) followed by SOD (R(2) = 0.91, P < 0.0001). Accessory LAAs show significant contractile properties on cardiac CT. Those accessory LAAs with a large sagittal height or depth should be evaluated for contractile properties, and if present should be examined for ectopic activity during electrophysiological studies.

Clinical Significance of Left Atrial Anatomic Abnormalities Identified by Cardiac Computed Tomography

“…We have demonstrated that accessory left atrial appendages are associated in patients with reported palpitations. The prevalence of accessory appendages in our investigation (28%) is in congruence with preceding studies which have shown prevalence between 10% -28% [6] [7] [9] [12] [21]. Moreover, accessory left atrial appendages have been implicated as the source of ectopy in patients with symptomatic atrial fibrillation refractory to medical treatment [16] [17].…”

Presence of accessory left atrial appendage/diverticula in a population with atrial fibrillation compared with those in sinus rhythm: a retrospective review

“…Their incidence has been reported to vary from 10 to 27%. Killeen et al recently identified 23 diverticula amongst a cohort of 102 patients and demonstrated contractile properties of the accessory left atrial appendages synchronous with that of the left atrium [10]. Subsequently they also identified ectopic activity within an accessory left atrial appendage.…”

Left atrial diverticula incidence during coronary CT angiography examination

“…In one case, a left atrial diverticulum was diagnosed in a 68-year-old female patient with mitral insufficiency; six months after surgical repair of the mitral valve, the atrial diverticulum had disappeared (10). Killeen et al (11) reported that atrial diverticula are continuous with the myocardial wall and fascia; as such, they may generate electrical activity, causing atrial arrhythmia.…”

“…Smooth and communicating diverticula are suggested to create a potential "loop" to trigger a transmission disorder (8,9,11,12). As coronary CTA is problematic in patients with disordered cardiac rhythms such as atrial fibrillation (13), these patients were excluded from our study, and thus the relationship between atrial fibrillation and the frequency of atrial diverticula could not be evaluated.…”