Arrhythmia Management in Complex Congenital Heart Disease

Figures

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  Figure 1. Transesophageal Echocardiography Before and After Leadless Pacemaker Implantation (A) Baseline anatomy consistent with double inlet single ventricle, showing both atria draining into a morphologic LV positioned on the right side, with an underdeveloped morphologic RV to the left. The oversewn mitral valve and intact tricuspid valve (atrioventricular valve) are visualized (red and white arrows, respectively), with the aortic root arising from the RV. (B) Postimplant image demonstrating the Micra AV leadless pacemaker (white arrow) anchored in the basal lateral aspect of the morphologic LV, below the atrioventricular valve (red arrow). Ao = aorta; LA = left atrium; LV = left ventricle; MV = mitral valve; RA = right atrium; RV = right ventricle; TV = tricuspid; VSD = ventricular septal defect.

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  Figure 2. Fluoroscopic Sequence of Leadless Pacemaker Implantation Via Transfenestration Approach in a Fontan Patient With Single-Ventricle Physiology Sequential fluoroscopic images illustrating (A) advancement of the 26-F DrySeal sheath across the trans-Fontan fenestration into the systemic atrium over an Amplatz SuperStiff wire; (B) deployment of the Micra AV leadless pacemaker via the delivery catheter across the atrioventricular valve; and (C) final positioning of the Micra AV within the morphologic left ventricle (systemic ventricle) along the lateral wall. The red arrow denotes the Micra AV; the white arrow denotes the DrySeal sheath. Pacing parameters at implantation: capture threshold 0.63 V at 0.24 ms, impedance 580 Ω, and R-wave amplitude 11.2 mV.

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  Figure 3. Electroanatomic Voltage Map of the Atria After Ablation Anatomical voltage map of the right and left atria on right anterior oblique projection showing areas of low voltage denoting scar, as well as final ablation lesion set along the cavomitral isthmus and lateral right atrium.

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  Figure 4. Surface Electrocardiography Before and After Leadless Pacemaker Implantation (A) Standard 12-lead ECG at baseline demonstrating IART with a cycle length of 270 ms and complete heart block, with underlying VVI epicardial pacing at 71 beats/min and a QRS complex width of 156 ms. (B) Postimplant ECG showing sinus rhythm with atrial sensed ventricular pacing at 60 beats/min from the Micra AV leadless pacemaker, with a narrow-paced QRS complex width of 112 ms. ECG = electrocardiogram; IART = intra-atria re-entrant tachycardia.