Relationship between complex fractionated atrial electrograms during atrial fibrillation and the critical site of atrial tachycardia that develops after catheter ablation for atrial fibrillation.

INTRODUCTION: Complex fractionated atrial electrograms (CFAEs) are a substrate modification target in patients with atrial fibrillation (AF). However, whether CFAEs can be also arrhythmogenic grounds of atrial tachycardia (AT) presenting after AF ablation remains to be determined. We investigated the relationship between CFAEs and the critical site of AT after CFAE-guided AF ablation. METHODS AND RESULTS: Seventy-two patients showing AT after pulmonary vein isolation and further CFAE-guided ablation were included. The termination sites of the 95 distinct ATs were annotated on color-coded CFAE cycle maps. Of the 95 ATs, 61 (64.2%) had a termination site at the border zone of CFAE or in a highly dense CFAE area. The cycle length (CL) of the ATs terminated in the CFAE area was significantly shorter than the CL of those terminated in the non-CFAE area. The cut-off CL for ATs terminated at the CFAE area was 270 milliseconds, with sensitivity/specificity of 70%/75%. In 67.2% of the ATs terminating at the CFAE-related area, the major termination sites were the anterior wall near the LA appendage, septum and roof, whereas the peri-mitral isthmus was the most common termination site of ATs in the non-CFAE area. CONCLUSIONS: The areas showing CFAE and their border zones were frequently associated with termination of ATs presenting after AF ablation. The mean CL of ATs originating near CFAEs was significantly shorter than that of those terminated in non-CFAE areas. The targeted CFAE areas also provided the arrhythmogenic milieu for AT developing after AF ablation.

Ablation of left atrial tachycardia with cycle length alternans after atrial fibrillation ablation: significance of fractionated electrogram mapping.

INTRODUCTION: Atrial tachycardia (AT) with cycle length alternans occurring after atrial fibrillation ablation has not been previously described. METHODS: Among 66 patients with left AT, stable AT with 2 alternating cycles was registered in 5 cases. Activation mapping of both alternating cycles was performed in all 5 patients. Entrainment and fractionated electrogram mappings were also carried out. RESULTS: Among 10 AT cycles, activation maps suggested underlying mechanism of 5 cycles (50%) in 3 patients. Entrainment pacing was helpful in 2 patients (confirmed mechanism of 2 AT cycles). Catheter ablation successfully terminated AT in all 5 patients: ablation of sites with fractionated potentials in 4 patients and mitral isthmus ablation in 1 patient. CONCLUSION: Consecutive activation mapping of both AT cycles is feasible for mechanism determination in some patients. The results of our small study suggest that fractionated electrogram-guided ablation might be a reasonable approach for termination of this type of AT.

Medium-term outcome of anatomically repaired congenitally corrected transposition: the double switch operation.

BACKGROUND: The double switch operation is emerging as the procedure of choice for congenitally corrected transposition of the great arteries. However, rhythm disturbances in the postoperative period are rarely discussed. METHODS AND RESULTS: Eighteen survivors who underwent corrective surgery for congenitally corrected transposition of the great arteries were followed up. Patients in group I (n=8), who also had a ventricular septal defect and pulmonary stenosis, had undergone the Senning plus Rastelli operation. Patients in group II (n=10), who did not have pulmonary stenosis, had undergone the Senning and arterial switch operation. The patients were followed up by periodical clinical examination, echocardiography and 24-hour Holter monitoring. In group I, follow-up ranged from 24 to 66 months (mean 44 months). There was no late death and all the patients are symptom free. There was no significant atrioventricular valve regurgitation and left ventricular function was normal. There were no rhythm disturbances. In group II, follow-up ranged from 2 to 72 months (mean 48 months). There were 2 late deaths due to atrial tachyarrhythmia and residual pulmonary hypertension 36 and 8 months after the procedure, respectively. One patient had significant mitral regurgitation and required mitral valve replacement. Three patients had recurrent atrial/junctional tachyarrhythmia: one of them was lost to follow-up after 1 year while another died of resistant atrial tachyarrhythmia. The third patient underwent mitral valve replacement for severe mitral regurgitation and developed complete heart block necessitating a permanent pacemaker implantation. CONCLUSIONS: Though good long-term results are obtained following the double switch operation, the problem of atrial arrhythmias still needs to be addressed suitably.

Effect of verapamil on right ventricular pressure and atrial tachyarrhythmia after thoracotomy.

We have studied the effect of verapamil on the incidence of ECG changes and right ventricular pressures (RVP) in 25 male patients (aged 62 (SD 9) yr) undergoing thoracotomy in a placebo-controlled double-blind trial. Verapamil 0.01 mg kg-1 h-1 (n = 12) or saline (n = 13) i.v. was started after surgery and continued on the first day after operation with oral verapamil 80 mg or placebo, 8-hourly. Haemodynamic data were collected before operation and on three days after operation with the patients breathing air and then 60% oxygen (FIO2 0.60) for 10 min. Atrial tachyarrhythmia (AT) (4/13) and new ischaemic ECG changes (3/13) occurred only in the control group (P less than 0.05). With an FI02 of 0.21, systolic RVP increased by 54% on the first two days after operation in the control group and by 13% in the verapamil group (P less than 0.02). With an FIO2 of 0.60 for 10 min, systolic RVP decreased more in the control than in the verapamil group (P less than 0.01). In the control group, an increase in end-diastolic RVP (P less than 0.001) and central venous pressure (P less than 0.05) on the first day after operation was predictive of AT occurring on the second day.