Comparison of Magnetic Navigation System and Conventional Method in Catheter Ablation of Atrial Fibrillation: Is Magnetic Navigation System Is More Effective and Safer Than Conventional Method?

BACKGROUND AND OBJECTIVES: Although there have been so many reports of catheter ablation of atrial fibrillation (AF) with magnetic navigation system (MNS), it is not necessarily obvious that MNS is more effective than conventional ablation. We performed AF ablation with MNS and compared the clinical outcomes and radiofrequency ablation parameters with those of conventional ablation. SUBJECTS AND METHODS: One hundred eleven consecutive patients (conventional group, n=70 vs. MNS group, n=41) undergoing catheter ablation of AF were enrolled. We compared and analyzed the procedural parameters, namely fluoroscopic time, procedural time, acute procedural success and 3 months success rate of both groups. RESULTS: The MNS group was associated with slightly larger left atrial size (43.7+/-6.3 mm vs. 41.2+/-6.3 mm, p=0.04), significantly longer total procedure time (352+/-50 minutes vs. 283+/-75 minutes, p<0.0001), and shorter total fluoroscopic time (99+/-28 minutes vs. 238+/-45 minutes, p<0.0001) than the conventional group. The MNS and conventional group did not differ with respect to acute procedural success, AF recurrence, atrial flutter/atrial tachycardia recurrence, or total arrhythmia recurrence. While no complications were observed in the MNS group, eight cases of significant pericardial effusion occurred in the conventional group. CONCLUSION: The MNS system seems to be effective and safe in the catheter ablation of AF, particularly in the population of patients with persistent AF and slightly dilated left atria.

Coronary Artery Flow Velocity Pattern Predicting Myocardial Recovery after Acute Anterior Myocardial Infarction

BACKGROUND AND OBJECTIVES: The relationship between the coronary artery flow velocity pattern on the distal left anterior descending coronary artery (LAD), using transthoracic Doppler echocardiography (TTE) and myocardial recovery, following an acute myocardial infarction (MI), has not been studied. SUBJECTS AND METHODS: The coronary flow velocity at the distal LAD was recorded with TTE, immediately, on the 7th day, and at an average, on the 10th month, in 36 patients following an acute anterior MI. The peak diastolic coronary flow velocity (PDV), the initial velocity pattern and alteration in the velocity pattern, during the follow-up period, were analyzed by the changes in the left ventricular systolic function and the anterior apical wall motion. The subjects were divided into two groups: the recovery (R) group:n=24, M:F=14:10, mean age=60+/-9 yrs;and the non-recovery (NR) group:n=12, M:F=11:1, mean age=61+/-11 yrs, according to their myocardial recovery status. RESULTS: The early flow velocity at the distal LAD, using TTE after MI, was divided into 4 patterns;a normal biphasic flow pattern, with a larger diastolic and a smaller systolic component; a pattern, with slow flow and deceleration slope;a pattern, with a retrograde flow; and a pattern, with a rapid diastolic deceleration slope and an early systolic reversal flow. A normal biphasic flow pattern was observed in 16 (66%) of the R-group (n=24), and 1 (8%) of the NR-group (n=12) (p=0.001) patients. A rapid diastolic deceleration slope and an early systolic reversal flow pattern was only observed in 4 of the NR-group (n=12) (p=0.003) patients. CONCLUSION: The patterns, with a rapid diastolic deceleration slope and a systolic retrograde flow, early after MI, and a persistent slow flow velocity during follow up, are related to poor myocardial recovery following an acute anterior MI.