What is the clinical evidence from this study?

Study design: Case-Control. Population: Paroxysmal atrial fibrillation (n=50). Intervention: Paroxysmal atrial fibrillation vs. Healthy controls. Primary outcome: Left atrial total emptying fraction (p=<0.001).

May 9, 2022Open Access

Left atrium phasic impairments in paroxysmal atrial fibrillation patients assessed by cardiovascular magnetic resonance feature tracking

Q: What are the key findings of this study?

Paroxysmal atrial fibrillation patients exhibited significantly lower left atrial total emptying fraction (53.4% vs 62.4%) and longitudinal strain compared to healthy controls.

Key Result

Paroxysmal atrial fibrillation patients exhibited significantly lower left atrial total emptying fraction (53.4% vs 62.4%) and longitudinal strain compared to healthy controls.

Study Design

Type

Case-Control (n=50)

Multicenter

Structured PICO

Does cardiovascular magnetic resonance feature tracking identify left atrial phasic impairments in patients with paroxysmal atrial fibrillation compared to healthy controls?

Population

50 adults (27 with paroxysmal atrial fibrillation and 23 healthy controls) underwent cardiovascular magnetic resonance feature-tracking to assess left atrial phasic function and deformation.

Exposure

Cardiovascular magnetic resonance (CMR) feature-tracking (FT) assessment of left atrial phasic function and deformation.

Comparator

Healthy controls without signs of AF who had a CMR indication per exclusion of suspected cardiac pathology.

Outcome

Left atrial phasic function and deformation (LA volume, LA emptying fraction, LA longitudinal strain, and LA strain rate in reservoir, conduit, and contractile phases).surrogate

Cardiovascular magnetic resonance feature tracking reveals significant impairments in left atrial phasic function and longitudinal strain in patients with paroxysmal atrial fibrillation prior to the development of permanent structural changes.

Main Result

Absolute Event Rate: 53.4% vs 62.4%

p-value: p=<0.001

Limitations

Single-centre study with a relatively small sample size
Did not stratify the risk of developing diastolic dysfunction
Controls were primarily women, which might impact the results due to lower myocardial mass
Lack of echocardiographic-based validation in the specific cohort
CMR-FT tracking process may be challenging due to the narrow left atrial wall

Abstract

Atrial fibrillation (AF) is an abnormal and irregular heartbeat caused by uncoordinated electrical impulses in the left atrium (LA), which could induce lasting changes in the heart tissue or could be a consequence of underlying cardiac disease. This study aimed to assess the left atrial phasic function and deformation in paroxysmal AF (PAF) patients-who had not received radiofrequency ablation and had no signs of permanent AF-using the cardiovascular magnetic resonance (CMR) feature-tracking (FT) technique. Fifty subjects (27 PAF patients and 23 controls) were included and examined with CMR. Their LA volume, LA function, LA longitudinal strain (LS) and LA strain rate were assessed in the LA reservoir, conduit, and contractile phases. PAF patients exhibited higher LA volumes than controls, while their LA emptying fraction and LA LS was significantly lower in all three phases. In contrast, the corresponding emptying volumes (total, passive and active) were similar in both groups. The LA volumetric rates from CMR-derived volume curves differed significantly in PAF patients vs controls in the reservoir and contractile phases. In contrast, the equivalent LV volumetric rates were similar. This study suggests that assessing the LA phasic function could offer insight into early LA impairments for PAF patients.

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