A 2:1 atrioventricular block in an adult patient with a Fontan circulation: from transesophageal pacing to echocardiographic guidance of epicardial pacemaker lead placement

Figures

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  Fig. 1. Schematic overview of patient’s anatomy. APD = arteria pumonalis dextra; APS = arteria pulmonalis sinistra; Fontan = extracardiac Fontan conduit; hLV = hypoplastic left ventricle; LIPV = left inferior pulmonary vein; LSPV = left superior pulmonary vein; NeoAo = neo-aorta with homograft patch to reconstruct aorta; RIPV = right inferior pulmonary vein; RSPV = right superior pulmonary vein; sRV = systemic right ventricle; TV = tricuspid valve; VCI = vena cava inferior; VCS = vena cava superior; VS = ventricular septum. ∗ indicates epicardial pacemaker leads placement.

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  Fig. 2. Atrioventricular block during exercise stress test. A 2:1 AV block occurred at atrial frequencies >100 bpm with recovery of the AV conduction at sinus rates of 80 to 100 bpm. Based on the 12-lead stress testing ECGs, discrimination between sinus tachycardia and 2:1 AV block during atrial tachycardia was challenging. AV = atrioventricular.

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  Fig. 3. Perioperative measurement of surrogates of cardiac output with and without sRV pacing using transesophageal echocardiography. The RVOT VTI with and without sRV pacing was respectively 12.3 cm (at a heart rate of 89 bpm) and 14.7 cm (at 71 bpm). Max PG = peak pressure gradient; mean PG = mean pressure gradient; RVOT = right ventricular outflow tract; sRV = systemic right ventricle; Vmax = maximum velocity; VTI = velocity time integral.

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  Fig. 4. Electrocardiographic and echocardiographic optimization during sRV pacing. The effect of sRV pacing compared to intrinsic AV conduction on the sRV (dys-)synchrony, systolic function and estimated cardiac output was assessed using transthoracic echocardiography. During sRV pacing, the RVOT VTI was 14.2 cm and the E and A wave were partially fused with a diastolic filling time of 52% of the RR interval. During intrinsic AV conduction, the RVOT VTI was 13.6 cm and the E and A wave were partially fused with a diastolic filling time of 46% of the RR interval. The heart rate frequency remained stable at ∼85 bpm during the two different AV delay intervals. Compared to intrinsic conduction, sRV systolic function, synchrony and tricuspid insufficiency remained unchanged during sRV pacing. AV = atrioventricular; RVOT = right ventricular outflow tract; sRV = systemic right ventricle; VTI = velocity time integral.

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  Fig. 5. Outpatient clinic echocardiography performed at 2.5 years of follow-up. sRV systolic function remained unchanged compared to preoperative status (C and D with pacing and G and H without pacing). Although 3D regional volumetric curves showed only a slight delay with pacing compared to without pacing (A vs. E), no measurable septal-to-lateral delay was observed with tissue doppler imaging with and without pacing (B vs. F).