Increased sympathetic activity after atrioventricular junction ablation in patients with chronic atrial fibrillation
Mohamed H. Hamdan, MD, FACCa,
Richard L. Page, MD, FACCa,
Clifford J. Sheehan, MDa,
Jason D. Zagrodzky, MDa,
Stephen L. Wasmund, BS*,
Karthik Ramaswamy, MDa,
Jose A. Joglar, MDa and
Michael L. Smith, PhD*
a University of Texas Southwestern Medical Center and Dallas Veterans Affairs Medical Center, Dallas, Texas, USA
* Department of Integrative Physiology, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas, USA
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Figure 1 Sample tracings of integrated SNA, femoral artery pressure and ablation catheter. These tracings show a 20-s period before the onset of RF ablation (RFA) and  40 s of RF ablation without AV block. The arrow indicates the onset of RF ablation. No significant changes in arterial pressure or SNA were produced by unsuccessful RF ablation (see Table 2).
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Figure 2 Sample tracings of integrated SNA, femoral artery pressure and surface ECG for one patient. The periods shown include a baseline period (during AF) just before the beginning of RF ablation and during RF ablation (arrow on ECG panel) in which AV block was achieved within 10 s, 10 min after AV block (pacing at 60 beats/min) and 12 min after AV block (pacing at 90 beats/min).
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Figure 3 Mean (±SEM) arterial pressures and SNA levels for all 10 patients at baseline (with atrial fibrillation [AFib]), during RF ablation (RFA) with AV block (first minute) and 10 min after AV block was achieved. Asterisks indicate significant differences from baseline (p < 0.05).
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Figure 4 Mean (±SEM) arterial pressures and SNA levels for all 10 patients during pacing rates of 60 and 90 beats/min after complete AV node block was achieved by RF ablation. The data for pacing at 60 beats/min were collected immediately before pacing at 90 beats/min. Asterisks indicate significant differences between pacing rates (p < 0.05).
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Figure 5 Monophasic action potential recordings obtained from the MAP catheter positioned at the RV apex during pacing at 120 beats/min. Top, Before ablation, APD90 was 229 ms and ERP was 200 ms, with evidence of capture at a coupling interval equal to 210 ms. Bottom, After ablation, APD90 increased to 258 ms and premature stimuli delivered at a coupling interval of 220 ms failed to capture. The ERP increased from 200 ms before ablation to 220 ms after ablation.
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