Initial palliation with bPAB enables AoV diameter growth in some patients, improving the likelihood of conventional total repair adaptation rate, particularly for CoA or IAA type A.
Sympathetic provocative testing is commonly used to detect the abnormal QT dynamics in long QT syndrome (LQTS) patients, particularly LQTS type 1 and type 2. However, little is known about LQTS type 3 (LQT3). We investigated QT dynamics during exercise testing in LQTS patients, particularly LQT3. This study included 37 subjects, comprising 16 genotyped LQTS patients and 21 unrelated healthy subjects without QT prolongation. LQTS patients were divided into LQT3 and non-LQT3 groups. During exercise tests using a modified Bruce protocol, 12-lead electrocardiogram monitoring was performed using a novel multifunctional electrocardiograph. QT intervals were automatically measured. The QT/heart rate (HR) relationship was visualized by plotting the beat-to-beat confluence of the recorded data. A linear regression analysis was performed to determine the QT/HR slope and intercept. Estimated QT intervals at HR 60 bpm (QT60) were calculated by the regression line formula. QT/HR slopes were steeper for each LQTS group than for the control group (P < 0.001). QT60 values demonstrated a moderate correlation with QT intervals at rest (P < 0.0001) for both groups. The corrected QT intervals (QTc) at 4 min of recovery after exercise were significantly longer in the non-LQT3 group than in the control group but were not different between the LQT3 and the control groups. Abnormal QT dynamics during exercise testing were observed in both LQT3 patients and other LQTS subtypes. This method may be useful for directing genetic testing in subjects with borderline prolonged QT intervals.
Introduction
Detailed three‐dimensional (3D) mapping has been useful for effective radiofrequency catheter ablation. The Rhythmia system can create atrio‐ventricular dual‐chamber mapping, which reveals the atrial and ventricular potentials all at once in the same map. The aim of this study was to investigate the utility of mapping the atrium and ventricle simultaneously with a high‐density 3D mapping system for the ablation of accessory pathways (AP).
Methods
From July 2015 to August 2020, 111 patients underwent ablation of APs. Dual‐chamber maps were created in 50 patients (median age 15 [10–54], 32 male [64.0%]), while 61 patients underwent radiofrequency (RF) ablation with conventional single‐chamber 3D maps. The background characteristics and procedural details were compared between the dual‐chamber mapping group and the conventional single‐chamber mapping group.
Results
The number of RF applications (median [IQR]; 1.0 [1.0–3.0] vs. 3.0 [1.0–6.0], p = .0023), RF time (median [IQR], s; 9.2 [2.0–95.7] vs. 95.6 [4.1–248.7], p = .0107), and RF energy (median [IQR], J; 248.4 [58.7–3328.2] vs. 2867.6 [134.2–7728.4], p = .0115) were significantly lower in the dual‐chamber group. The fluoroscopy time (median [IQR], min; 19.9 [14.2–26.1] vs. 26.5 [17.7–43.4], p = .0025) and fluoroscopy dose (median [IQR], mGy; 52.5 [31.3–146.0] vs. 119.0 [43.7–213.5], p = .0249) were also significantly lower in the dual‐chamber than single‐chamber mapping group.
Conclusion
The dual‐chamber mapping was useful for ablating accessory pathways and reducing the number of RF applications, total RF energy, and radiation exposure as compared with traditional mapping techniques.
Assessment of QT dynamics is feasible on fully automated QT interval measurement with this ECG recorder. Further studies are required in larger populations to confirm the accuracy and precision of QT measurement and QT dynamics using this new multifunctional ECG.
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