Small left atrial volume and dimension before ablation are predictors of tachycardia-induced cardiomyopathy with atrial fibrillation

Masahiro Nauchi MD, Tsuyoshi Sakai MD, Yuta Sugizaki MD, Naohiko Sahara MD

Department of cardiovascular center, Saiseikai Yokohamashi Tobu Hospital

We express our thank to Akatsu, medical technologists, and members of Clinical research support center at Saiseikai Yokohamashi Tobu Hospital. We would like to thank Enago (www.enago.jp) for the English language review.

The authors declare no conflicts of interest associated with this manuscript.

Corresponding Author: Masahiro Nauchi

Saiseikai Yokohamashi Tobu Hospital

3-6-1 Shimosueyoshi, Tsurumi Ward, Yokohama city, Kanagawa, Japan.

E-mail address:m_nauchi@tobu.saiseikai.or.jp

Tel +81 45 576 3000

Fax +81 45 576 3525

Abstract

Introduction

Tachycardia-induced cardiomyopathy (TCM) is a reversible cause of heart failure with impaired left ventricle (LV) function. However, the diagnosis is difficult before treatment or control of the arrhythmia for the first time. This study was to clarify the characteristics of TCM with atrial fibrillation (AF) before AF ablation.

Methods

In this retrospective observational study, we observed 31 patients with paroxysmal or persistent AF who had impaired LV function without structural heart disease and who underwent catheter ablation. We defined impaired LV function as LV ejection fraction (LVEF) <50% on the initial or worst echocardiogram. After ablation, the LVEF became <60% (Group 1; n = 9) or ≧60% (Group 2; n = 22). We compared the differences in baseline characteristics between the two groups. A receiver operating curve with area under the curve (AUC) was used to evaluate the prediction efficiency. The optimal cutoff point of the AUC was at which sensitivity and specificity would be maximal.

Results

There were significant differences in left atrial (LA) volume (LAV) by computed tomography (CT), LAV adjusted by body surface area (LAVI) by CT, LAVI by echocardiography, and LA diameter (LAD) (p < 0.05, respectively). The AUCs were 0.859, 0.869, 0.798, and 0.750, respectively. The optimal cutoff points were 147 ml, 79 ml/m², 37 ml/m², and 45.8 mm, respectively.

Conclusion

Small LAV, LAVI by CT, LAVI by echocardiography, and LAD were predictors of LVEF improvement. Small LA volume and dimension before ablation may be useful for diagnosis of TCM with AF.

Key words: Tachycardia-induced cardiomyopathy, Arrhythmia-induced cardiomyopathy, atrial fibrillation, catheter ablation, heart failure

Abbreviations

TCM, tachycardia induced cardiomyopathy

HF, heart failure

LV, left ventricular/ventricle

AF, atrial fibrillation

EF, ejection fraction

DCM, dilated cardiomyopathy

CMR, cardiac magnetic resonance

CT, computed tomography

LA, left atrial/atrium

LAV, left atrial volume

LAVI, left atrial volume index

BSA, body surface area

PV, pulmonary vein

LAA, left atrial appendage

PVI, pulmonary vein isolation

CIED, cardiac implantable electronic device

ROC, receiver operating characteristic

AUC, area under curve

CI, confidence interval

LAD, left atrial diameter

1 Introduction

TCM is one of Arrhythmia-induced cardiomyopathies and a reversible cause of HF with impaired LV function. AF is the most common cause of TCM^1,2. We cannot always observe echocardiographic data in typical TCM at the first occurrence: LVEF is <30%, LV end-diastolic diameter is <65 mm, and LV end-systolic diameter is <50 mm³. The diagnosis is determined by a recovery of LV function within 3 months after treatment or control of the arrhythmia⁴. In other words, we cannot determine the diagnosis for at least 3 months after arrhythmia control. Moreover, the diagnosis is determined by excluding other causes of cardiomyopathy, especially idiopathic DCM. Absence of late Gadolinium enhancement on CMR imaging has been useful for excluding other causes⁵. However, it is an unusual method and is difficult for patients with impaired renal function.

Thus, the purpose of this study was to clarify the characteristics of TCM with AF before AF ablation. These should help establish early and optimal examinations, such as transesophageal echocardiography or CT, and treatments, such as AF ablation or cardioversion.

2 Methods

2.1 Study design and study population