In vivo contact force measurements and correlation with left atrial anatomy during catheter ablation of atrial fibrillation.
OBJECTIVE
Lesion formation during catheter ablation crucially depends on catheter-tissue contact. We sought to evaluate the impact of anatomical characteristics of the left atrium (LA) and the pulmonary veins (PVs) on contact force (CF) measurements.


RESULTS
An anatomical map of the LA was obtained in 25 patients prior to catheter ablation of atrial fibrillation. Contact force (operator blinded) and local bipolar electrogram amplitudes (EGM) were measured in eight pre-defined segments around the PVs. After unblinding, points with low CF (≤5 g) were corrected to CF >5 g, and the distance between points was measured. In a pre-procedural computed tomography of the heart, LA volume as well as sizes and circumferences of the PV ostia were measured and correlated to CF measurements. Four hundred and twenty-six points in eight pre-defined LA locations were assessed. Low CF (<5 g) was found in 25.0% (43.5%) of points superior, 33.3% (66.7%) anterior, 32.1% (44.4%) inferior, and 15.5% (15.9%) posterior to the right (left) PVs. The mean distance after correction was 5.8 ± 3.4 mm. Local bipolar electrogram amplitudes between low- and high-CF points did not differ (1.21 ± 1.54 vs. 1.13 ± 1.3 mV, P = ns). The mean CF at the left PVs was significantly lower than at the right PVs (7.91 ± 3.74 vs. 13.95 ± 6.34 g, P < 0.001), with the lowest CF anterior to the left PVs (5.2 ± 3.6 g). Contact force measurements did not correlate to LA volume, size, and circumference of the PVs.


CONCLUSIONS
Contact force during LA mapping significantly differs according to the location within the LA. These differences are independent of LA volume and anatomy of the PV ostia.
Cardiology and Angiology I, Heart Center, Freiburg University, Freiburg, Germany.
Fabienne
F
Schluermann
Department of Radiology, University Hospital, Freiburg, Germany.
Tobias
T
Krauss
Cardiology and Angiology I, Heart Center, Freiburg University, Freiburg, Germany.
Juergen
J
Biermann
Cardiology and Angiology I, Heart Center, Freiburg University, Freiburg, Germany.
Maximilian
M
Hartmann
Cardiology and Angiology I, Heart Center, Freiburg University, Freiburg, Germany.
Luca
L
Trolese
Department of Radiology, University Hospital, Freiburg, Germany.
Gregor
G
Pache
Cardiology and Angiology I, Heart Center, Freiburg University, Freiburg, Germany.
Christoph
C
Bode
Cardiology and Angiology I, Heart Center, Freiburg University, Freiburg, Germany stefan.asbach@universitaets-herzzentrum.de.
Stefan
S
Asbach
D000368:Aged; D020517:Atrial Appendage / Q000601:surgery*; D001281:Atrial Fibrillation / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D005260:Female; D006325:Heart Atria / Q000033:anatomy & histology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D011667:Pulmonary Veins / Q000601:surgery*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
Area of pulmonary veins; Atrial fibrillation; Circumference of pulmonary veins; Contact force; Left atrial volume