Distribution and area of low voltage and dense scar zones and their relation to left atrial enlargement in ablation-naïve patients with paroxysmal atrial fibrillation

Tchavdar Shalganov,Boyan Kunev,Milko Stoyanov,Metodi Mirazchiyski

doi:10.3897/bgcardio.26.e56371

Abstract

There is paucity of studies correlating the left atrial (LA) dilation and the LA total and abnormal voltage areas in patients with atrial ﬁ brillation (AF). We sought to determine the area of LA and its segments by high-density mapping in patients with paroxysmal AF, and to correlate the LA dilation deﬁ ned by echocardiography with the total and the abnormal LA areas. Material and Methods. Retrospective study of patients with paroxysmal AF and pulmonary vein isolation proceeded by high-density mapping in sinus rhythm. All had transthoracic echocardiography and LA dilation, if present, was graded as mild/moderate-severe. LA voltage was deﬁ ned as low (< 0.5 mV) or scar (< 0.1 mV). The LA was divided in 5 segments and the total and segmental area, low voltage area and scar area were measured. Data were presented as mean ± SD or median and interquartile interval (25-75%) depending on normality of distribution. Shapiro-Wilk test, Spearman T correlation, Kruskal-Wallis, and ANOVA analysis were used. A p-value < 0.05 was considered significant. Results. Sixty-seven patients (66% males) were studied. LA enlargement was present in 58% (mild enlargement in 39%, moderate/severe in 19%). Low voltage and scar areas were found in both groups with and without LA dilation. Moderate correlation was found between the percentage of abnormal area and the degree of LA dilation (none vs mild vs moderate/severe), rho = 0.44, p = 0.0002. In patients with non-dilated LA the mean total LA area was 100.4 ± 17 cm2 and the abnormal area was < 10% (9.9%, 6.2-14.8%), with barely detectable scar. In patients with LA enlargement the total area was approximately 10% larger (109.8 cm2, 100.9-123.8 cm2), however the abnormal area was almost doubled (17.1%, 11.1-26.8%), and there were small yet measurable dense scar areas. Conclusions. Low voltage LA areas < 0.5 mV were found universally by high-density mapping in patients with paroxysmal AF, irrespective of the presence of LA enlargement. However, only patients with LA enlargement had measurable scar areas. The total abnormal area correlated moderately with the degree of LA dilation deﬁ ned by echocardiography.

Highlights

Предсърдното мъждене (ПМ) е заболяване, което е свързано с дилатация и фиброза на лявото предсърдие (ЛП), наред с други фактори [1-3]
The total abnormal area correlated moderately with the degree of left atrial (LA) dilation defined by echocardiography
We investigated how the LA dilation defined by transthoracic echocardiography correlated with the total and the abnormal LA areas, both measured by high-density mapping

Summary

PATIENTS WITH PAROXYSMAL ATRIAL FIBRILLATION

Целта ни беше да определим площта на ЛП и сегментите му с високоплътностен мепинг при пациенти с пристъпно ПМ, и да корелираме ехографски установената ЛП дилатация с общата и абнормната ЛП площ. Беше установена умерена корелация между относителния дял на абнормната площ и степента на ЛП дилатация (липсваща с/у лека с/у умерена/тежка), rho = 0.44, p = 0.0002. При пациенти без ЛП дилатация средната обща ЛП площ беше 100.4 ± 17 cm, а абнормната площ беше < 10% (9.9%, 6.2-14.8%), с почти липсващ цикатрикс. При пациенти с ЛП дилатация общата площ беше с около 10% по-голяма (109.8 cm2, 100.9-123.8 cm2), но абнормната площ беше почти двойно по-голяма (17.1%, 11.1-26.8%), с малка, но измерима цикатрисиална площ. ЛП зони с нисък волтаж < 0.5 mV се откриват повсеместно с високоплътностен мепинг при пациенти с пристъпно ПМ, независимо дали има ЛП дилатация. Изолация на белодробни вени, ехокардиография, високоплътностен мепинг, волтажен мепинг, плътен цикатрикс

Абнормна площ

Заднолатерална Posterolateral

Не е деклариран конфликт на интереси

Findings

No conflict of interest was declared