case_images: PMC10808459_01
case_images: (A) A 12-lead ECG with atrial tachycardia and widely split P' waves. P'1 morphology was biphasic, and P'2 morphology was positive in the inferior leads. The P'2 wave almost merged with the QRS complex. (B) An intracardiac ECG during atrial tachycardia. The earliest atrial activation was at CS1-2. CS, coronary sinus; ECG, electrocardiogram.
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case_images: PMC10808459_01_fcvm-10-1303200-g001.jpg
case_images: F1
case_images: P' waves were prolonged in duration (ca. 220 ms) and were widely split in morphology (P'1 wave morphology was biphasic and P'2 wave morphology was positive in the inferior leads; the P'2 wave almost merged with the QRS complex) (Figure 1). The intracardiac ECG showed that the earliest atrial activation developed in the distal coronary sinus (CS), indicating that focal AT originated from the left atrium (Figure 1). The ECG recorded after the procedure showed a P wave in sinus rhythm, while the widely split P waves appeared to be absent (Supplementary Figure S1).
case_images: (A) Voltage mapping of the left and right atria. A low-voltage area was defined as contiguous areas of bipolar voltage <0.5 mV. Purple represents areas with relatively normal voltages, and the other colors represent low-voltage areas. (B) An electrophysiological mapping of the left atrium with atrial tachycardia. The white star represents the earliest activation point in the LAA. The white arrows represent the direction of atrial activation. LAA, left atrial appendage.
case_images: fcvm-10-1303200-g002.jpg
case_images: PMC10808459_01_fcvm-10-1303200-g002.jpg
case_images: F2
case_images: Voltage mapping demonstrated a wide distribution of low-voltage areas in the left atrium, suggesting slow conduction between the left and the right atria, including the Bachmann bundle zone (Figure 2). The left atrial anterior line was blocked (Figure 2).
case_images: An intracardiac ECG shows the earliest activation. The yellow dotted line and blue ball represent the earliest activation.
case_images: fcvm-10-1303200-g003.jpg
case_images: PMC10808459_01_fcvm-10-1303200-g003.jpg
case_images: F3
case_images: The tachycardia originated from the LAA, as confirmed by the mapping (Figure 3).