Premature Atrial Stimulation Accentuates Conduction Abnormalities in Cardiac Surgery Patients that Develop Postoperative Atrial Fibrillation

BACKGROUND: postoperative atrial fibrillation (POAF) is a common cardiac surgery complication that is associated with increased complications and negative outcomes, but the association between presurgical atrial conduction abnormalities and POAF has not been investigated clinically during premature atrial S1S2 stimulation. This clinical study sought to examine whether intraoperative premature atrial stimulation reveals increased areas of slowed and/or blocked conduction in patients that develop POAF. METHODS: High-density intraoperative epicardial left atrial mapping was conducted in 20 cardiac surgery patients with no prior history of atrial fibrillation (AF). In 20 patients, 6 (30%) developed POAF. A flexible array of 240-electrodes was placed on the posterior left atrial wall in between the pulmonary veins. Activation maps were generated for sinus and premature atrial S1S2 stimulated beats. The area of conduction block (CB), conduction delay (CD) and the combination of both (CDCB) for conduction velocity <0.1, 0.1 ≤ x ≤ 0.2; x < 0.2 and < 0.2 m/s, respectively were quantified. RESULTS: For a premature atrial S2 beat with shortest cycle length captured, conduction velocity maps revealed a significantly higher area for CD (13.19 ± 6.59 versus 6.06 ± 4.22 mm2, p = 0.028) and CDCB (17.36 ± 8.75 versus 7.41 ± 6.39 mm2, p = 0.034), and a trend toward a larger area for CB (4.17 ± 3.66 versus 1.34 ± 2.86 mm2, p = 0.063) in patients who developed POAF in comparison to those that remained in the sinus. Sinus and S1 paced beats did not show substantial differences in abnormal conduction areas between patients with and without POAF. CONCLUSION: In comparison to sinus and S1 beats, premature atrial S2 beats accentuate conduction abnormalities in cardiac surgery patients that developed POAF.

Abstract 17255: Premature Atrial Stimulation Reveals Increased Conduction Slowing and Block in Cardiac Surgery Patients That Develop Postoperative Atrial Fibrillation

Introduction: Postoperative atrial fibrillation (POAF) is a common cardiac surgery complication that is highly associated with increased morbidity and mortality. The relation of presurgical left atrial (LA) conduction abnormalities and POAF during intraoperative premature atrial stimulation (S1S2) pacing is investigated and reported. Hypothesis: Intraoperative premature atrial stimulation reveals increased areas of slowed or blocked conduction in patients that develop POAF. Methods: High-density intraoperative epicardial mapping was conducted in 20 cardiac surgery patients with no history of preoperative atrial fibrillation (AF) both in sinus rhythm (SR) and during S1S2 pacing. A flexible array comprised of 240 electrodes was placed on the posterior LA wall in between the pulmonary veins. For each patient, the area of conduction block (CB), conduction delay (CD) and combined conduction delay and block (CDCB) for conduction velocity <0.1 m/s, 0.1 - 0.2 m/s and <0.2 m/s, respectively were quantified. Results: In 20 patients, 6 (30%) developed POAF. As shown in the Figure, conduction maps revealed the presence of significantly higher areas of CD (13.2±6.6% vs. 6.1±4.2%, p=0.03) and CDCB (17.5±8.7% vs. 7.4±6.4%, p=0.03), and a trend toward larger CB (4.2±3.8% vs. 1.3±2.9%, p=0.09) in patients that developed POAF for premature atrial beat S2 compared to patients that remained in SR after cardiac surgery. S1 paced beats and SR did not show significant differences in abnormal conduction percentages between patients with and without POAF. Conclusions: Premature atrial stimulation accentuates conduction abnormalities in cardiac surgery patients that develop POAF, revealing a pre-surgical substrate that may indicate greater risk for post-surgical atrial arrhythmias.

Increasing eff ectiveness method of conservative treatment of typical atrial fl utter

Purpose — to study the effi cacy and safety of transesophageal atrial stimulation in combination with intravenous administration of amiodarone in comparison with pharmacological or device cardioversion in patients with typical atrial fl utter (AF). Material and methods. 129 patients with a typical paroxysmal or persistent AF were examined. The average patients age was 57.87 ± 7.43 years. The eff ectiveness and safety of pharmacological cardioversion with amiodarone iv, electrical cardioversion, transesophageal atrial stimulation, combined, if necessary, with intravenous amiodarone were compared. Conclusion. Statistically signifi cant diff erences were not found in the frequency of sinus rhythm achievement for diff erent types of a typical AF classical conservative treatment. The amiodarone addition during transesophageal atrial stimulation leads to a signifi cant increasing in the effi cacy in comparison with pharmacological cardioversion (p = 0.0380).