Electrophysiological anatomy of typical atrial flutter: the posterior boundary and causes for difficulty with ablation.
BACKGROUND
The electrophysiological anatomy of cavotricuspid isthmus-dependent atrial flutter (CVTI-AFL) has not been fully elucidated.


METHODS
We studied 602 autopsied human hearts from individuals aged 0 to 103 years. We measured morphological features of the right atrium, including the crista terminalis (CT), pectinate muscles, sub-Eustachian pouch, Thebesian valve (TV), and the coronary sinus (CS) ostium.


RESULTS
In adults, the mean right atrium dimensions were 4.7 cm x 4.5 cm x 4.4 cm. Pectinate muscles extended medial to the CT in 54% of hearts. In 19% of hearts, these ended in another ridge termed the second CT. Pectinate muscles extended into the CVTI in 70% of hearts. A sub-Eustachian pouch was present in 16% of hearts, was always located on the septal CVTI, and was more likely when a prominent TV was also present. A TV, present in 62% of all hearts, covered the inferior quadrant of the CS ostium in 9% of these hearts.


CONCLUSIONS
The posterior boundary of the reentrant circuit of CVTI-AFL comprises the Eustachian ridge and CT, but in some patients may also include a second CT. Sub-Eustachian pouches on the septal CVTI are strongly associated with a prominent TV. The lateral CVTI can have prominent pectinate muscles. This comprehensive characterization of the electrophysiological anatomy of the reentrant circuit of CVTI-AFL may provide guidance and improve success during difficult ablations.
Midwest Heart Specialists, Elmhurst, Illinois, USA.
Apoor S
AS
Gami
William D
WD
Edwards
Nirusha
N
Lachman
Paul A
PA
Friedman
Deepak
D
Talreja
Thomas M
TM
Munger
Stephen C
SC
Hammill
Douglas L
DL
Packer
Samuel J
SJ
Asirvatham
D001282:Atrial Flutter / Q000000981:diagnostic imaging* / Q000473:pathology*; D002102:Cadaver; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging / Q000473:pathology*; D006329:Heart Conduction System / Q000000981:diagnostic imaging* / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D011859:Radiography; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity