Intermittent PR Prolongation During Narrow QRS Complex Tachycardia

Figures

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  Visual Summary. Flow Chart of Case Presentation AT = atrial tachycardia; AV = atrioventricular; DAVNP = dual atrioventricular nodal pathways; ECG = electrocardiogram; EP = electrophysiological; LA = left atrium; LAA = left atrial appendage; RA = right atrial; VA = ventriculoatrial.

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  Figure 1. Initial 12-Lead Electrocardiogram Showing Tachycardia The PR interval on the 8th beat was normal (blue arrow), but the PR interval on the 9th beat was longer (green arrow). The P-wave on the 10th beat was not apparent, but it was found that the P-waves of the 10th and 11th beats were fused into the T-wave, and each P-wave could be subsequently measured, appearing upright behind the QRS complex with the conduction of 1:1 to the ventricle (red arrows).

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  Figure 2. Three-Dimensional Electroanatomical Mapping of The Target in LAA (A) Three-dimensional electroanatomical mapping of the LA showed the earliest activation located at the apex of the LAA (yellow circle). (B) Both precise mapping image with circular and intracardiac electrograms confirmed the apex of the LAA as the earliest activation area (green arrow). (C) The ablation target area at the LAA apex, indicated with the colored dots. CS = coronary sinus; LAA = left atrial appendage; LIPV = left inferior pulmonary vein; LSPV = left superior pulmonary vein.

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  Figure 3. The Specific Locations of Each Catheter Under Fluoroscopy (A) LAA angiography was performed to confirm the correct positioning of the circular mapping catheter (Lasso-15) within the LAA. (B) The TactiCath catheter was positioned at the apex of the LAA for ablation. ABL = ablation catheter; CS = coronary sinus; LAA = left atrial appendage; RV = right ventricular electrode.

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  Figure 4. Electrophysiology Assessment Before and After Catheter Ablation (A) Intracardiac electrograms: the conduction sequence of atrial tachycardia was CS12 leading, the P-wave in lead I was negative, and the possibility of left atrial origin should be considered. (B) After ablation at the apex of the LAA, when sinus rhythm was restored, the sequence of CS activation changed from distal to proximal, and the P-wave in lead I converted to positive. (C) Ventriculoatrial dissociation was observed during RV S1S1 at 500 ms. RA = right atrium.