Haemodynamic deterioration following radiofrequency ablation of the atrioventricular conduction system

Introduction. Radiofrequency ablation of the atrioventricular conduction system has become an established therapy for patients with drug-refractory atrial fibrillation. We observed 14 patients with hemodynamic deterioration related to worsening of mitral regurgitation after the procedure. Patients and methods. We retrospectively evaluated 256 consecutive patients with drug-refractory atrial fibrillation referred for radiofrequency ablation of the AV node and implantation of a pacemaker. Because we found hemodynamic deterioration related to worsening mitral regurgitation, we compared the clinical history, electrophysiologic and echocardiographic data from the patients with hemodynamic deterioration and worsening mitral regurgitation (group A) with those without hemodynamic deterioration (group B). Results. Fourteen out of 256 patients (group A) undergoing ablation of the atrioventricular conduction system deteriorated with acute pulmonary edema (3 patients) or congestive heart failure (11 patients) at a mean of 6 weeks after the ablation procedure. Four of these patients were referred for mitral valve surgery. The length of the procedure and the number of applications during ablation were similar in both groups. Compared with group B patients, group A patients had significantly higher left ventricular end-diastolic diameters (64 +/- 6 mm vs 56 +/- 9 mm; p < 0.05) at baseline despite similar left ventricular end-systolic diameters, fractional shortening and grade of mitral regurgitation (1.15 +/- 1.05 vs 1.11 +/- 0.97). Moreover, whereas no change was observed in left ventricular end-diastolic diameter, left ventricular end-systolic diameter, fractional shortening and grade of mitral regurgitation in group B patients after ablation, group A patients experienced a significant increase in left ventricular end-diastolic diameter (64 +/- 6 mm vs 72 +/- 9 mm; p < 0.01) and grade of mitral regurgitation (1.15 +/- 1.05 vs 2.90 +/- 1.15; p < 0.01). In patients operated on no ablation related structural damage to the mitral valve apparatus could be detected. The worsening of the mitral regurgitation was related to dilation of the mitral valve annulus. Conclusions. Hemodynamic deterioration together with progression of mitral regurgitation is a potential complication of ablation of the atrioventricular conduction system.