PMC9845542_01
Baseline electrocardiogram tracing demonstrating ventricular pre-excitation of left anterolateral accessory pathway. The QRS complexes are significantly different from those with maximal pre-excitation in Figures 2 and 3.
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Her baseline ECG demonstrated ventricular pre-excitation with a pattern consistent with left anterolateral accessory pathway (Figure 1).
Surface electrocardiogram tracing of abrupt transition from atrial fibrillation to atrial flutter. Note the somewhat irregular pre-excited QRS complexes with abrupt transition to very rapid, regular, and maximally pre-excited QRS complexes.
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Induced orthodromic reciprocating tachycardia converted into atrial fibrillation with a single-interval SPERRI of 228 ms; however, the majority of R-R intervals were in the range of 350-400 ms (Figure 2). A-V accessory pathway conduction with maximally pre-excited QRS complexes (Figures 2 and 3) and loss of demonstrable cardiac output. Atrial flutter terminated spontaneously to normal sinus rhythm during preparation for DC cardioversion.
Intracardiac electrograms demonstrating the transition from atrial fibrillation with variable accessory pathway (AP) conduction to atrial flutter and consistent 1:1 AP conduction.
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A-V accessory pathway conduction with maximally pre-excited QRS complexes (Figures 2 and 3) and loss of demonstrable cardiac output. Atrial flutter terminated spontaneously to normal sinus rhythm during preparation for DC cardioversion.