Elsevier

Heart Rhythm

Volume 8, Issue 9, September 2011, Pages 1364-1371
Heart Rhythm

Focus issue: Atrial fibrillation: Clinical
Atrial fibrillation
Stiff left atrial syndrome after catheter ablation for atrial fibrillation: Clinical characterization, prevalence, and predictors

https://doi.org/10.1016/j.hrthm.2011.02.026Get rights and content

Background

There have been no studies of atrial diastolic function after catheter ablation of atrial fibrillation (AF). We encountered a few patients with symptomatic left atrial (LA) diastolic dysfunction and associated pulmonary hypertension (PH) that developed after catheter ablation for atrial fibrillation. Similar findings were described in patients after cardiac surgery and were referred to as the “stiff left atrial syndrome.”

Objective

The purpose of this study was to prospectively quantify the incidence of patients developing PH associated with diastolic hemodynamic abnormalities of the LA after radiofrequency ablation of AF and to identify the possible predictors.

Methods

Between January 2009 and July 2010, data on 1,380 consecutive patients were prospectively collected. Before ablation and at follow-up, all patients had an echocardiogram to assess for the presence of PH. Patients with no echocardiographic evidence of PH but complaining of unexplained dyspnea with LA diastolic abnormalities were evaluated with right heart catheterization (RHC). Patients were included in the analysis if they developed new or worsening PH postablation with evidence of LA diastolic dysfunction by RHC or direct LA pressure measurement. All patients were evaluated for pulmonary vein stenosis and excluded if this condition was identified.

Results

The mean age was 62 ± 11 (75% male), and nonparoxysmal AF was the predominant arrhythmia (71%). New or worsening PH with associated LA diastolic abnormalities was detected in 19 (1.4%) patients after ablation. The prevalence of PH did not differ between AF types (P = .612). Compared with patients who did not develop PH, LA scarring (P <.001), diabetes (P = .026), and obstructive sleep apnea (OSA; P = .006) were more frequently observed among those who developed PH. In a multivariable logistic model, preprocedure LA size ≤45 mm (odds ratio [OR] = 6.13; P = .033), mean LA pressure (OR 1.14; P = .025), severe LA scarring (OR = 4.4; P = .046), diabetes mellitus (OR = 9.5; P = .004), and OSA (OR = 6.2; P = .009) were independently associated with the development of PH postablation.

Conclusions

After radiofrequency catheter ablation of atrial fibrillation (RFCAF), PH with LA diastolic dysfunction or the so-called stiff LA syndrome is a rare but potentially significant complication of AF ablation. Severe LA scarring, LA ≤45 mm, diabetes mellitus, OSA, and high LA pressure are clinical variables that predict the development of this syndrome. The main clinical findings include dyspnea, congestive heart failure, PH, and large V waves on pulmonary capillary wedge pressure (PCWP) or LA pressure tracings in the absence of mitral regurgitation.

Introduction

Catheter ablation has greatly improved the care of patients with atrial fibrillation (AF). Catheter ablation has proven to be superior to antiarrhythmic drugs for relief of symptoms and improvement of quality of life.1 For patients with persistent and longstanding persistent AF, more extensive ablation has resulted in higher success rates.2, 3

As operators strive to increase success rates with more extensive ablation, the question becomes, How much is too much? In an effort to answer this question, authors have examined the systolic function and size of the left atrium (LA) after ablation.

A recent metanalysis of 17 trials examining atrial function after catheter ablation of AF concluded that successful ablation significantly decreases LA size and volumes and does not seem to adversely affect LA systolic function.4 There have been no publications examining the diastolic function or compliance of the LA after catheter ablation. It is possible that scar tissue formation after ablation may adversely impact the diastolic properties of the LA.

We present a case series of patients who have developed dyspnea and pulmonary hypertension (PH) associated with diastolic hemodynamic abnormalities of the LA after catheter ablation of AF. Sniderman and colleagues5, 6 referred to similar findings in patients after cardiac surgery as the “stiff LA syndrome.”

Section snippets

Methods

Since the first documented case of stiff LA syndrome postablation was discovered at Scripps in 2008, we prospectively assessed 1,380 consecutive patients before and after AF ablation for the presence of new or worsening PH, dyspnea, and LA diastolic pressure abnormalities at Texas Cardiac Arrhythmia Institute (Austin, TX), Scripps Clinic (San Diego, CA), California Pacific Medical Center (San Francisco, CA), and Metro Health Hospital (Cleveland, OH) in the period between January 2009 and April

Definition of PH

PH was defined as resting mean pulmonary artery pressure (PAP) ≥25 mmHg or ≥30 mmHg during exercise according to the American College of Cardiology Foundation/American Heart Association 2009 expert consensus document on PH7 and was classified as mild, moderate, or severe based on clinical symptoms and echocardiographic variables.

Echocardiographic evaluation of PH

Pulmonary artery systolic pressure was calculated by adding the peak pressure gradient derived from the tricuspid regurgitation (TR) signal to the estimated right atrial (RA) pressure. The RA pressure was estimated from the inferior vena cava by standard techniques. If the TR signal was suboptimal, then agitated saline was used to enhance the measurement. We then used the Syyed formula (Mean PAP = 0.65 × Systolic PAP + 0.55 mm of Hg) to calculate the mean PAP.8, 9, 10

RHC

A single 8-Fr sheath was placed into the right common femoral vein. A 7-Fr balloon tip Swan-Ganz catheter was advanced under fluoroscopy into the right pulmonary artery and pulmonary wedge position. RA, right ventricular, pulmonary artery, and pulmonary wedge pressures were recorded. Fick and thermodilution cardiac outputs were calculated.

Definition of LA scar

The technique used for mapping and defining categories of LA scar was reported elsewhere.11 Briefly, electroanatomic mapping of the LA was performed using the Carto system (Biosense Webster Inc., Diamond Bar, CA). Scar was defined as an area with a bipolar voltage amplitude ≤0.05 mV. The area of scarred segments of LA was expressed as percentage of total LA surface area (assessed by same technique) excluding tubular portions of the PVs. Three categories of LA scarring were developed based on

Ablation protocol

Our ablation protocol has been extensively described elsewhere.3, 12 Briefly, we perform pulmonary vein (PV) antrum isolation guided by intracardiac echocardiography and by a circular mapping catheter. In patients with paroxysmal AF, the antrum of the PV and the portion of the posterior wall contained within the PV area are electrically isolated. In patients with persistent and longstanding persistent AF, the electrical isolation of the PVs is extended to the entire posterior wall down to the

Follow-up

Follow-up visits were scheduled in the outpatient clinic at 3, 6, and 12 months. All patients were discharged on therapeutic warfarin and on AADs previously ineffective, except for amiodarone. A 48-hour or a 7 -day Holter monitor was obtained at 3, 6, 9, 12, and 15 months postablation. All patients were offered an event recorder for 5 months and were asked to transmit recordings 4 times a week even when asymptomatic and any time they experienced symptoms.3, 12

Statistical analysis

Continuous data were described as mean ± standard deviation and as counts and percent if categorical. Student's t-test, χ2-test, and Fisher's exact test were used to compare differences across groups. Multivariable logistic regression was used for identifying significant predictors of PH. All potential confounders were entered into the model based on known clinical relevance or significant association observed in univariate analysis.

Controlling variables used in the model were age, AF type,

Results

A total of 1,380 patients underwent AF ablation in our centers during the study period. The baseline characteristics of this cohort are presented in Table 1. In this series (age 62 ± 11, male 75%), nonparoxysmal AF was the predominant arrhythmia (71%), LA scar was observed in 29% of patients, and 469 (34%) were undergoing a redo procedure.

Characteristics of patients with PH

PH was detected in 19 (1.4%) patients after the catheter ablation. Out of the 19 patients, 4 (21%) presented with paroxysmal AF (PAF), while 15 (79%) patients had nonparoxysmal AF at baseline (P <.001). Mild PH was observed in 10 (53%) patients, moderate in 6 (32%) patients, and severe PH in 3 (15%) patients (P <.001). All patients with severe PH had preexisting moderate PH with evidence of LA diastolic dysfunction before ablation. At the last follow-up, the average PA systolic pressure was 45

Predictors of PH

As observed in univariate analysis, patients with PH were more likely to have LA scarring (79% vs. 28%; P <.001), diabetes (26% vs. 9%; P = .006), and OSA (42% vs. 16%). Incidence of LV diastolic dysfunction was not significantly different between patients with and without PH (3 [16%] in the PH and 268 [20%] in the non-PH group; P = 1.000; Table 3).

The association between baseline risk factors and postprocedure PH was assessed in a multivariable logistic model. After adjusting for potential

Follow-up

Our follow-up included 7-day Holter monitoring (86% of our patients, 1,191), and 16% (223 patients) had 48-hour Holter monitoring at 3, 6, 9, and 12 months of follow-up. The compliance was 93% (1,108 patients) for the 7-day Holter, and 100% (223 patients) for the 48-hour Holter monitoring. Compliance with the follow-up protocol was carried out by a team of dedicated AF nurses.

Complications

Two pericardial effusions requiring pericardiocentesis, one phrenic nerve palsy, and six groin hematomas (0.43%) were observed. Patients were discharged after one night in the hospital. No other major complication such as atrioesophageal fistula or PV stenosis/occlusion was seen.

Discussion

To our knowledge, this is the first report of dyspnea and associated diastolic LA dysfunction after catheter ablation of AF. The incidence is low, but individual patients can become significantly symptomatic. The main clinical findings are dyspnea, congestive heart failure, PH, and large V waves recorded on PCWP or LA pressure tracings in the absence of significant mitral regurgitation. Large V waves are generated as blood flows into a noncompliant LA. Smaller positive deflections at the

Study limitations

Patients were identified based on the presence of symptoms, LA pressure tracings at the time of ablation, and echocardiographic assessment of PAPs. Many echocardiograms do not have a tricuspid regurgitation signal that is sufficient for measurement of PAP. This methodology may underestimate the incidence of PH postablation particularly if patients are minimally symptomatic. Minimally symptomatic patients with stiff LA who did not have repeat ablation and did not have a TR signal on

Conclusions

Stiff LA syndrome after catheter ablation for AF is a potential complication of the procedure but has a low prevalence. Small LA, OSA, diabetes mellitus, atrial scarring, and high LA pressure predict patients who could manifest the syndrome. Awareness of this syndrome might assist clinicians in the recognition and treatment of these patients.

Acknowledgments

The authors thank Drs. Shane Bailey, MD, and Sanghamitra Mohanty, MD, for their support in this study.

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The first two authors contributed equally to this study and should be considered as the first author.

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