Evaluation of the cavotricuspid isthmus and right atrium by multidetector-row computed tomography in patients with common atrial flutter

Abstract

The sizes of the right atrium (RA), cavotricuspid isthmus, and Eustachian valve are predictors of success of radiofrequency catheter ablation for atrial flutter (AFL). We examined the relationship between the sizes of cavotricuspid isthmus as measured by multidetector-row computed tomography (MDCT) and fluoroscopy. We used eight-detector MDCT to measure the tricuspid isthmus of 23 patients prior to linear ablation for common AFL. One patient with a deep pouch in the RA was excluded. Parameters measured were (1) the length of the trace of isthmus (Ti), which was equivalent to the blocking line; (2) the size of the tricuspid isthmus (DTi); and (3) the distance from the tricuspid valve and inferior vena cava (IVC) (LDTi). DTi and LDTi indicate the size of the RA, reflecting the appropriately sized steerable ablation catheter, respectively. Of the 22 patients, 21 were ablated successfully without recurrence of AFL, and clinical success was achieved in one additional patient despite failure to obtain a bidirectional block. Ti, DTi, and LDTi were correlated with fluoroscopy time (r = 0.84, r = 0.88, and r = 0.88, respectively; P < 0.0001), total delivered energy (r = 0.81, r = 0.80, and r = 0.83, respectively; P < 0.0001), and application time (r = 0.84, r = 0.80, and r = 0.87, respectively; P < 0.0001). Measurement of the tricuspid isthmus by MDCT may noninvasively provide important information for successful linear ablation.

Successful Catheter Ablation of Typical Atrial Flutter in a Patient with a Long Vertical and Diverticulum‐Like Cavotricuspid Isthmus

“…4 Recently, MDCT and three-dimensional intracardiac echography can provide more detailed intracardiac structure and could be helpful for increasing the efficiency of AFL ablation. 4,5 In this patient, a long vertical vestibule and diverticulumlike morphology of CTI that has not been described before was demonstrated in the right anterior oblique projection of the right atrial angiography. By using the conventional continuous pullback technique, the CTI was difficult to be ablated completely because of complex morphology of CTI.…”

“…Three different angiographic morphologies of CTI were reported with straight, concave, and pouch‐like recesses in which concave morphology and pouch‐like recesses CTI would account for much longer ablation time 4 . Recently, MDCT and three‐dimensional intracardiac echography can provide more detailed intracardiac structure and could be helpful for increasing the efficiency of AFL ablation 4,5 . In this patient, a long vertical vestibule and diverticulum‐like morphology of CTI that has not been described before was demonstrated in the right anterior oblique projection of the right atrial angiography.…”

The deeper the pouch is, the longer the radiofrequency duration and higher the radiofrequency energy needed—Cavotricuspid isthmus ablation using intracardiac echocardiography

“…Among these CTI variations, the presence of a pouch, long CTI, and prominent Eustachian ridge/valve have been shown to be the factors related to a longer RF duration. 4,5,8,11,12 Da Costa, et al 4 reported that the CTI characteristics, such as the concavity and the presence of a pouch, are the factors that increase the procedure duration. In particular, the presence of a pouch increased the RF duration even though the length of the CTI was short.…”

“…7 Recently, various imaging studies, including angiography, multiple-detector computed tomography, transthoracic echocardiography (TTE), transesophageal echocardiography, and intracardiac echocardiography (ICE), have been used to evaluate the isthmus. [4][5][6][7][8][9][10][11][12][13][14][15][16][17] In particular, using ICE provides a direct visualization and detailed assessment of the CTI anatomy and facilitates the ablation procedure. 7,[14][15][16][17] However, to the best of our knowledge, there have been no studies that have investigated the geometry of the CTI precisely with ICE and the occasional need for a knuckle-curve ablation during the CTI ablation.…”

The change in the tissue characterization detected by magnetic resonance imaging after radiofrequency ablation of isthmus-dependent atrial flutter

“…The previous studies showed that the specific anatomy of the CTI may be one of the causes for the difficulties with non-successful CTI ablation [4][5][6][7][8][9]. Evidence for such anatomical characteristics has been reported by angiographic studies [6,7], multi-slice computed tomography [10,11], and cardiac magnetic resonance (CMR) imaging study [8,9]. In addition, the endocardial surface complexity, wall thickness along the CTI [4,7,11], and ablation mediated tissue edema might play a crucial role in formation of conduction gaps and non-transmural lesions along the ablation line [5,[12][13][14].…”