heart movement during respiration cycle

The reason I am bringing this up is that I had no idea how much the heart moved because of respiration. This is important for imaging the heart as the devices have to compensate for movement. Today, one of the mapping/ablation companies announced a new way to compensate for respiration so that an EP can be more precise with the catheter tip locations during mapping and ablation. The movement (both translational and rotational) from respiration is quite significant. I now understand better why the more experienced operators seem to be more "aggressive" with forceful catheter contact compared to EPs coming up on learning curve. The ability of the catheter tip to maintain contact with any spot is suspect without force, the downside is that steampop risk (tamponade) increases significantly with increased contact force.
=================
Respiratory Motion of the Heart From Free Breathing Coronary Angiograms
Guy Shechter,corresponding author Cengizhan Ozturk, Jon R. Resar, and Elliot R. McVeigh
Author information ► Copyright and License information ►
The publisher's final edited version of this article is available at IEEE Trans Med Imaging
See other articles in PMC that cite the published article.
Abstract
Respiratory motion compensation for cardiac imaging requires knowledge of the heart's motion and deformation during breathing. This paper presents a method for measuring the natural tidal respiratory motion of the heart from free breathing coronary angiograms. A three-dimensional (3-D) deformation field describing the cardiac and respiratory motion of the coronary arteries is recovered from a biplane acquisition. A cardiac respiratory parametric model is formulated and used to decompose the deformation field into cardiac and respiratory components. Angiograms from ten patients were analyzed. A 3-D translation motion model was sufficient for describing the motion of the heart in only two patients. For all patients, the heart translated caudally (mean, 4.9 ± 1.9 mm; range, 2.4 to 8.0 mm) and underwent a cranio-dorsal rotation (mean, 1.5° ± 0.9°; range, 0.2° to 3.5°) during inspiration. In eight patients, the heart also translated anteriorly (mean, 1.3 ± 1.8 mm; range, −0.4 to 5.1 mm) and rotated in a caudo-dextral direction (mean, 1.2° ± 1.3°; range, −1.9° to 3.2°).

[www.ncbi.nlm.nih.gov]



Edited 1 time(s). Last edit at 10/12/2015 12:06PM by researcher.

There will be an article published in Circulation that is related to this topic and it addresses the role of contact-force measurement to either improve contact or to maintain a certain range within what the manufacturers recommend for optimal lesions. It is difficult to remain in range because of systolic motion and respiration motion. Looks like the effects are half and half and I am not sure how the authors determined that since the two cycles have such different cycle periods.

The availability of CF information from Smarttouch and Tacticath shines a spotlight on Einstein's famous quote - “The more I learn, the more I realize how much I don't know.”

The abstract is below.

================
Abstract
BACKGROUND:
-In an experimental model variable and intermittent contact force (CF) resulted in a significant decrease in lesion volume. In humans, variability of CF during pulmonary vein isolation (PVI) has not been characterized.
METHODS AND RESULTS:
-In 20 consecutive patients undergoing CF guided circumferential PVI 914 radio-frequency applications (530 in sinus rhythm (SR) and 384 in atrial fibrillation (AF)) were analyzed. The variability of the 60% CF range (CF60%) was 17±9.6 grams. Hundred seventy-one (19%) applications were delivered with constant, 717 (78%) with variable and 26 (3%) with intermittent CF. The mean CF and Force Time Integral (FTI) were significantly higher during applications with variable than with intermittent or constant CF. There was no significant difference in CF variability, CF60% variability and FTI between applications delivered in SR and AF. The main reasons for CF variability were systolo-diastolic heart movement (29%) and respiration (27%). In 10 additional patients, during adenosine induced AV block the minimum CF significantly increased at 19 sites (5.3±4.4 vs. 13.4±5.9 grams, p<0.001) and at 16 sites intermittent or variable CF became constant. At only one site systolo-diastolic movement remained the main reason for variable CF.
CONCLUSIONS:
-CF during PVI remains highly variable despite efforts to optimize contact. CF and CF parameters were similar during SR and AF. The main reasons for CF variability are systolo-diastolic heart movement and respiration. The systolo-diastolic peaks and nadirs of CF are due to ventricular contractions at the large majority of PVI sites.

[www.ncbi.nlm.nih.gov]