Pressure frequency characteristics of the pericardial space and thorax during subxiphoid access for epicardial ventricular tachycardia ablation.
BACKGROUND
Nonsurgical subxiphoid pericardial access may be useful in ventricular tachycardia ablation and other electrophysiologic procedures but has a risk of right ventricular puncture.


OBJECTIVE
The purpose of this study was to identify a signature pressure frequency that would help identify the pericardial space and guide access.


METHODS
The study consisted of 20 patients (8 women and 12 men; mean age 59.1 +/- 14.2 years; left ventricular ejection fraction 25.2% +/- 12.2%; failed 1.8 +/- 0.5 endocardial ablations; unresponsive to 2.0 +/- 1.0 antiarrhythmic drugs; 6 ischemic cardiomyopathy, 12 nonischemic cardiomyopathy, 2 normal heart; 4 previous sternotomy) undergoing epicardial ventricular tachycardia ablation. After pericardial access was obtained, a 10Fr long sheath was used to record pressure inside the pericardium and pleural space. Pressures were analyzed using a fast Fourier transform to identify dominant frequencies in each chamber.


RESULTS
Mean pressures in the pleural space and the pericardium were not different (7.7 +/- 1.9 mmHg vs 7.8 +/- 0.9 mmHg, respectively). However, the pericardial space in each patient demonstrated two frequency peaks that correlated with heart rate (1.16 +/- 0.21 Hz) and respiratory rate (0.20 +/- 0.01 Hz), whereas the pleural space in each patient had a single peak correlating with respiratory rate (0.20 +/- 0.01 Hz).


CONCLUSIONS
The pericardial space demonstrates a signature pressure frequency that is significantly different from the surrounding space. This difference may make minimally invasive subxiphoid pericardial access safer for nonsurgeons and may have important implications for electrophysiologic procedures.
Division of Cardiovascular Medicine, University of Virginia, Charlottesville, Virginia 22908, USA. mahapatra@virginia.edu
Srijoy
S
Mahapatra
Jason
J
Tucker-Schwartz
David
D
Wiggins
George T
GT
Gillies
Pamela K
PK
Mason
George
G
McDaniel
Damien J
DJ
Lapar
Christopher
C
Stemland
Eduardo
E
Sosa
John D
JD
Ferguson
T Jared
TJ
Bunch
Gorav
G
Ailawadi
Mauricio
M
Scanavacca
D017115:Catheter Ablation / Q000009:adverse effects / Q000379:methods*; D004594:Electrophysiology; D005260:Female; D005583:Fourier Analysis; D006352:Heart Ventricles / Q000293:injuries; D006801:Humans; D008297:Male; D008875:Middle Aged; D010496:Pericardium; D011312:Pressure; D011446:Prospective Studies; D012307:Risk Factors; D013223:Statistics as Topic; D056346:Sternotomy; D013318:Stroke Volume; D017180:Tachycardia, Ventricular / Q000601:surgery*; D013909:Thorax; D013997:Time Factors; D016277:Ventricular Function, Left