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Magnetocardiography detects left atrial dysfunction in patients with paroxysmal atrial fibrillation: comparison with healthy subjects
A.-Y. Her1
,
E.-S. Shin2
,
Y.H. Kim1
,
J.-W. Park3
,
1Kangwon National University Hospital, Department of Internal Medicine, Division of Cardiology - Chuncheon - Korea Republic of
,
2Ulsan University Hospital - Ulsan - Korea Republic of
,
3Charite - Campus Benjamin Franklin - Berlin - Germany
,
Topic(s): Arrhythmias, General – Diagnostic Methods: Non-invasive Diagnostic Methods
Background: PAF can lead to heart failure or a stroke. Magnetocardiography (MCG) is a non-invasive, contactless technique and to characterize the magnetic field, a pseudo-current conversion was used. The role of MCG in detecting left atrial (LA) dysfunction in patients with PAF is unknown.
Purpose: The aim of this study was to compare magnetic fields between patients with paroxysmal atrial fibrillation (PAF) and healthy subjects to identify possible indices to diagnose PAF.
Methods: We enrolled a total of 70 subjects including 26 healthy volunteers (group 1) and 22 marathon runners (group 2) who were all in sinus rhythm and acted as controls, and 22 patients with PAF (group 3) which was documented by electrocardiography (ECG). We calculated the PQ segment fluctuation score as the multiplication of the determined sum. Spatiotemporal activation graph (STAG) was reconstructed from the two dimensional pseudo-currents. The maximum value of LA pseudo-current under rest and peak exercise were measured between the end of the P wave and beginning of the Q wave.
Results: The peak value of PQ segment fluctuation score was higher in PAF patients (group 3) compared to other groups (1.6±1.1% in group 3 vs. 0.7±0.6% in group 1 vs. 0.9±0.9% in group 2, p=0.003). LA pseudo-current increase at peak exercise in PAF patients was significantly lower than in healthy volunteers and marathon runners (0.4±0.3 pT in group 3 vs. 0.8±0.3 pT in group 1 vs. 1.1±0.5 pT in group 2, p<0.001). PAF patients had less pseudo-current increase in STAG at peak exercise than healthy and marathon runners (46% of 26 PAF patients, 81% of 22 healthy subjects vs. 81% of 22 marathon runners, p=0.002). Sensitivity, specificity, and the area under the receiver-operator characteristics curve of LA pseudo-current increase at peak exercise for differentiating PAF patients from healthy subjects were 77%, 92%, and 0.896.
Conclusions: MCG can provide important non-invasive information for detecting LA dysfunction in patients with PAF. Therefore, MCG may help in differentiating PAF patients from healthy subjects.
Table 1. MCG data of groups at rest and stress
Variables
Group 1 (Healthy, n=26)
Group 2 (Runners, n=22)
Group 3 (PAF, n=22)
p-value
The peak value of PQ fluctuation score, %
0.7±0.6
0.9±0.9
1.6±1.1
0.003
The percent change of PQ segment fluctuation score at rest and stress, %
-62.5±0.6
-55.4±39.3
-18.6±64.9
0.003
The increase of STAG of PQ interval at stress, n (%)
21 (81)
21 (81)
12 (46)
0.002
The peak value of LA pseudo-current, pT
0.8±0.3
1.1±0.5
0.4±0.3
<0.001
The difference of LA pseudo-current between rest and stress, pT
0.5±0.3
0.7±0.4
0.2±0.3
<0.001
The percent change of LA pseudo-current at rest and stress, %
151.6±101.8
222.5±132.7
80.2±126.3
0.001
Magnetocardiographic data of groups at rest and stress.
