Acute hemodynamic effects of the Marshall-Plan ablation on left and right atrial pressure: does 'respecting atrial physiology' prevent stiff left atria? A retrospective single- center analysis
Authors: Poley P , Agdirlioglu T , Weil J , Krahnefeld O 
Published: May 2024

Abstract

Introduction
Stiff left atrium (STILA)-syndrome is a relevant concern after extensive ablation in the left atrium (LA) e.g. in persistent atrial fibrillation (AF). STILA often causes disabling heart failure symptoms worse than the initial arrhythmia symptoms. Therefore preventing adverse ablation-induced hemodynamic effects is of utmost concern.

Methods
This single-center study retrospectively analyzed data from 89 consecutive patients who underwent biatrial ablation for AF following the Marshall-Plan between February 2022 and November 2023. The procedures included ablation of the CTI and PVI where necessary followed by ablation of a LA roof line and ablation of the lateral mitral isthmus after previously performed ethanol ablation of the vein of Marshall. This lesion set is considered to maintain physiological activation of the LA. This study evaluates acute hemodynamic changes following the Marshall-Plan.
Invasive hemodynamic measurements of mean left and right atrial pressure, as well as A- and V-waves were performed in all patients before and after the ablation. We assessed the acute changes of atrial hemodynamics in these procedures.
Continuous data are given as mean ± standard deviation, categorical data are expressed as number and percentages. Differences between groups were determined by Student’s t-test, chisquare-test, and Fisher’s exact test using SPSS software. A p-value of &lt;0.05 was deemed significant.

Results
The patients' mean age was 70.1 ± 7.5 years and 39.0% were female. Mean BMI was 28.9 ± 5.2 kg/m². Procedures were performed under general anesthesia (with a PEEP of 5.5cmH2O (2-10 cmH2O)) and took 181 minutes on average. Left atrial mean pressure averaged at 15.7mmHg before the procedure. The overall average change of left atrial mean pressure was +1,8mmHg. The average change in left atrial A- and V-Wave amounted to -1.9mmHg and -0.9mmHg respectively.
The pre-procedural average right atrial mean pressure was 12.1mmHg. Right atrial mean pressure inclined by +1.6mmHg. The average change in right atrial A- and V-Wave was +0.6mmHg and +1.1mmHg respectively. The i.v. administered volume averaged 1900 ± 285ml. 3.3% of patients showed an increase of mean LA-pressure &gt;9mmHg. Those patients tended to be older (74.3years), were all male (100%) and had a higher BMI (31.5 kg/m²) as well as higher amount of i.v. administered volume (2333ml) and a longer procedure (213min).

Discussion
Complex and extensive biatrial ablation following the Marshall-Plan does not lead to acute significant increases in left or right atrial pressures. The administered i.v. volume might explain the slight increases observed. In our observation, the rate of significant increases in LA-pressure is low. This suggests that disrupting the (left) atrial activation pattern might play a role in the development of diastolic dysfunction and thereby STILA-syndrome. Respecting atrial physiology may be beneficial for preventing adverse hemodyamic changes after ablation.