Navigating Arrhythmias in Tetralogy of Fallot Throughout the Lifespan: A Case-based Review

Figures

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  Figure 1. Junctional ectopic tachycardia (JET). (A) Postoperative JET at a rate of 160 bpm. (B) Restoration of sinus rhythm with intact AV conduction and an underlying right bundle branch block after amiodarone therapy. AV, atrioventricular.

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  Figure 2. Intra-atrial re-entrant tachycardia (IART). (A) An IART with predominant 2:1 conduction. Complete right bundle branch block is noted along with right ventricular hypertrophy. (B) After the administration of 6 mg of intravenous adenosine, transient 3:1 conduction allows atrial activity (blue arrows) to be better appreciated, confirming a cycle length of approximately 300 milliseconds.

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  Figure 3. Nonautomatic focal atrial tachycardia (NAFAT). (A) A 3-dimensional electroanatomic activation map in a left anterior oblique view with a caudal tilt. Activation times are color-coded, from red (earliest) to purple (latest). Radial spread of activation from a focal source at the anterior margin of the inferior vena cava (IVC) is observed. The yellow spheres indicate the position of the His bundle. (B) Termination of the NAFAT during the first radiofrequency application (≤1.1 seconds). Shown are surface leads II, avF, V1, and V6, and intracardiac electrograms recorded from distal (ABLd) and proximal electrode pairs of the ablation catheter (ABLd), distal (HISd) and proximal (HISp) His bundle catheter, proximal (CS9-10) to distal (CS1-2) coronary sinus, and right ventricular apex (RVA). The red As and blue Vs indicate atrial and ventricular electrograms, respectively. SVC, superior vena cava.

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  Figure 4. Postoperative AV block. The electrocardiogram shows AV sequential pacing (ie, atrial sensing with ventricular pacing) in a patient with a dual chamber epicardial pacemaker. The lead placed on the left ventricle produces a typical paced right bundle branch block pattern. AV, atrioventricular.

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  Figure 5. Electrophysiology study before peripulmonary valve replacement. (A) Monomorphic ventricular tachycardia (VT) at a cycle length of 257 milliseconds is induced. Activation mapping could not be performed in VT due to haemodynamic instability, prompting antitachycardia overdrive pacing. Three-dimensional electroanatomic maps in sinus rhythm are shown in anteroposterior (B) and posteroanterior (C) views. Voltages ≥1.5 mV are represented in purple (normal tissue), whereas scar (≤0.5 mV) is color-coded red. Right (RPA) and left (LPA) pulmonary arteries, right ventricular outflow tract (RVOT) patch, right ventricular (RV) apex, pulmonary valve annulus, ventricular septal defect (VSD) patch, and the tricuspid valve are identified. Pace mapping was performed at the potential critical isthmuses for macroreentrant VT. The best pace map (D; 92% match) was obtained at the level of the asterisk along the isthmus between the VSD patch and pulmonary valve annulus.