Less is known about atrial remodeling and atrial tachyarrhythmias (ATa) in arrhythmogenic right ventricular cardiomyopathy (ARVC); this cross-sectional study aimed to determine the prevalence, characterization, and predictors of atrial remodeling and ATa in a large series of patients with ARVC. From February 2004 to September 2014, 294 consecutive patients who met the task force criteria for ARVC were enrolled. The prevalence, characterization, and predictors of atrial dilation and ATa were investigated. Right atrium (RA) dilation was identified in 160 patients (54.4%) and left atrium dilation in 66 patients (22.4%). Both RA and left atrium dilation were found in 44 patients (15.0%). Twenty-five patients (8.5%) had atrial fibrillation (AF), whereas 19 patients (6.5%) had atrial flutter (AFL). Of which, 7 patients (2.4%) had both AF and AFL. Multivariate analysis showed that AFL (odds ratio [OR] 10.309; 95% confidence interval [CI] 2.770 to 38.462; p <0.001), hypertension (OR 9.174; 95% CI 2.364 to 35.714; p = 0.001), and RA dilation (OR 6.993; 95% CI 1.623 to 30.303; p = 0.009) were associated with increased risk for AF. AF (OR 10.526; 95% CI 2.786 to 40.000; p = 0.001) increased the risk of AFL. In conclusion, atrial remodeling and ATa were common in patients with ARVC.
Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiomyopathy characterized predominantly by ventricular arrhythmias, right ventricular dysfunction, and sudden cardiac death. At present, less is known about atrial remodeling and atrial tachyarrhythmias (ATa) in ARVC. Atrial remodeling and ATa often coexist and interact with each other, which increase the risk of inappropriate implantable cardioverter defibrillator (ICD) shocks, thromboembolism events, and even bradyarrhythmias. This study aimed to assess the prevalence, characterization, and predictors of atrial remodeling and ATa in a large series of patients with ARVC.
Methods
From February 2004 to September 2014, consecutive patients who had a definite diagnosis of ARVC in our hospital were enrolled. The diagnosis of ARVC was based on the criteria set by the Task Force of the Working Group of Myocardial and Pericardial Disease of the European Society of Cardiology and of the Scientific Council on Cardiomyopathies of the International Society and Federation of Cardiology and was rechecked according to the 2010 revised Task Force Criteria.
All patients underwent transthoracic echocardiogram (TTE) and magnetic resonance imaging (MRI). The TTE and MRI parameters of the 4 cardiac chambers were abstracted. The right atrium (RA) dilation was defined as RA diameter ≥40 mm in vertical section to atrial septum, and the right ventricle (RV) dilation was defined as RV transverse diameter ≥40 mm in 4-chamber view in the end-diastolic. The left atrium (LA) dilation was defined as LA diameter ≥36 mm in parasternal long-axis view in the end-diastolic. The TTE and MRI data were evaluated independently by 2 groups of doctors without knowledge of clinical data, and inconsistencies between the TTE and MRI were adjudicated by a third cardiologist.
A careful interview of ATa history including atrial fibrillation (AF) and atrial flutter (AFL) was performed in all patients. In addition, all patients underwent 24 hours Holter and 48 hours telemetry monitoring. Paroxysmal AF was defined as AF that terminated spontaneously or with intervention within 7 days of onset, and persistent AF was defined as continuous AF sustained beyond 7 days.
Statistical analyses were performed using SPSS 19.0 software (SPSS Inc., Chicago, Illinois). Continuous variables were described as mean ± SD, and comparison between groups were performed with the Student’s t test or Wilcoxon test. Categorical variables were described as counts and compared by the chi-square analysis. For the multivariate logistic regression analysis, the continuous variables were appropriately transformed where required to render them normally distributed. The following variables included gender, age, presence of hypertension, and diabetes mellitus; parameters of cardiac chambers and left ventricular ejection fraction were analyzed to evaluate in association with the presence of atrial dilation and ATa. All tests were 2 tailed, and a statistical significance was established at a p <0.05.
Results
From February 2004 to September 2014, 312 consecutive patients with ARVC were admitted in our hospital. Of these, 18 patients with contraindication (ICD implanted) to MRI examination were excluded from the study. Therefore, there were 294 patients enrolled. The clinical characteristics were listed in Table 1 .
| Age, (years) | 37.7 ± 14.8 |
| Male | 221 (75.2%) |
| Right ventricle dilation | 200 (68.0%) |
| Mean left ventricle dimension, (mm) | 47.4 ± 6.0 |
| Mean left ventricular ejection fraction, (%) | 58.7 ± 11.4 |
| Hypertension | 27 (6.6%) |
| Diabetes mellitus | 8 (1.9%) |
| Task force criteria | |
| Epsilon wave | 50 (17.0%) |
| Prolonged terminal activation duration | 98 (33.3%) |
| Negative T waves | 189 (64.3%) |
| V 1 -V 3 or beyond | 143 (48.6%) |
| V 1 -V 4 or beyond with complete right bundle branch block | 21 (7.1%) |
| V 1 -V 2 | 15 (5.1%) |
| V 4 -V 6 | 8 (2.7%) |
| Left bundle branch block ventricular tachycardia with superior axis | 249 (84.7%) |
| Premature ventricular contractions > 500/24h | 71 (24.1%) |
| Structural major task force criteria | 142 (48.3%) |
| Structural minor task force criteria | 95 (32.3%) |
| Family history | 33 (11.2%) |
The prevalence of atrial dilation and ATa were shown in Figure 1 . In patients with LA dilation, 44 (66.7%) had RA dilation. In patients with RA dilation, 43 (26.7%) had LA dilation. Of the 25 patients with AF, 9 (3.1%) were persistent AF, and the other 16 were paroxysmal AF. The median time of the recorded episodes of ATa to the initial presentation of ARVC was 9 months (1 to 226 months). The AFLs recorded in all the 19 patients were cavotricuspid isthmus dependent based on 12-lead surface electrocardiogram, whereas 4 were confirmed by electrophysiological studies. The maximum ventricular rates noted with AF or AFL were 210 and 172 bpm, respectively. No sustained atrial tachycardia was found.
The comparisons of clinical characteristics in patients with and without atrial dilation were shown in Table 2 . Multivariate analysis showed that RV dilation (odds ratio [OR] 7.519; 95% confidence interval [CI] 3.906 to 14.493; p <0.001), LV dysfunction (OR 8.475; 95% CI 2.591 to 27.778; p <0.001), and LV dilation (OR 6.154; 95% CI 1.277 to 29.654; p = 0.024) were associated with increased risk for RA dilation. LV dilation (OR 12.987; 95% CI 2.564 to 66.667; p = 0.024) increased the risk of LA dilation.
| With (n = 182) | Without (n = 112) | P-Value | |
|---|---|---|---|
| Age, (years) | 33.5 ± 6.4 | 35.7 ± 14.8 | 0.067 |
| Male | 139 (76.4%) | 82 (73.2%) | 0.689 |
| Mean arrhythmogenic right ventricular cardiomyopathy history, (months) | 11.2 ± 27.6 | 8.3 ± 24.4 | 0.359 |
| Right ventricle dilation | 154 (84.6%) | 46 (41.1%) | < 0.001 |
| Mean left ventricle dimension, (mm) | 47.6 ± 6.5 | 47.1 ± 5.1 | 0.460 |
| Mean left ventricular ejection fraction, (%) | 57.0 ± 12.8 | 61.4 ± 7.8 | 0.001 |
| Moderate to severe tricuspid regurgitation | 52 (28.6%) | 8 (7.1%) | < 0.001 |
| Moderate to severe mitral regurgitation | 4 (2.2%) | 2 (1.8%) | 0.808 |
| Atrial fibrillation/atrial flutter | 28 (15.4%) | 9 (8.0%) | 0.065 |
| Hypertension | 17 (9.3%) | 10 (9.8%) | 0.905 |
| Diabetes mellitus | 7 (3.8%) | 1 (0.9%) | 0.131 |
The comparisons of patients with and without ATa were listed in Table 3 . RA dilation (OR 6.993; 95% CI 1.623 to 30.303; p = 0.009), AFL (OR 10.309; 95% CI 2.770 to 38.462; p <0.001), and hypertension (OR 9.174; 95% CI 2.364 to 35.714; p = 0.001) were associated with increased risk for AF. AF (OR 10.526; 95% CI 2.786 to 40.000; p = 0.001) increased the risk of AFL.
