S. Azzopardi

Pulmonary vein isolation: The impact of pulmonary venous anatomy on long-term outcome of catheter ablation for paroxysmal atrial fibrillation

BACKGROUND Circumferential pulmonary vein (PV) isolation is the cornerstone of catheter ablation for atrial fibrillation (AF); however, PV reconnection remains problematic. OBJECTIVE To assess the impact of PV anatomy on outcome after AF ablation. METHODS One hundred two patients with paroxysmal AF underwent cardiac magnetic resonance (60%) or computed tomography (40%) before AF ablation. PV anatomy was classified according to the presence of common PVs, accessory PVs, PV branching pattern, and the dimensions of the PV ostia, intervenous ridges (IVRs), and the left PV-left atrial appendage ridge. RESULTS Four discrete PVs were present in 48(47%) of the patients: a left common PV in 38(37%), a right common PV in 2(2%), an accessory right PV in 20(20%), and left PV in 4(4%). At a mean follow-up of 12 ± 4 months, 75 of 102 (74%) patients were free of recurrent AF. A LCPV was associated with an increase in freedom from AF (87% vs 66% for 4 PV anatomy; P = .03). Greater left IVR length (16.9 ± 3.5 mm vs 14.0 ± 3.0 mm; P ≤ .001) and width (1.4 ± 0.6 mm vs 1.1 ± 0.6 mm; P = .02) were associated with increased AF recurrence. After multivariate analysis, abnormal anatomy (LCPV or accessory PV) and left IVR length were found to be the only independent predictors of freedom from AF. CONCLUSIONS Four discrete PVs are present in the minority of patients with paroxysmal AF undergoing PV isolation. The presence of a LCPV is associated with an increased freedom from AF after catheter ablation. PV anatomy may in part explain the variable outcome to electrical isolation in patients with paroxysmal AF.

Magnetic resonance post-contrast T1 mapping in the human atrium: validation and impact on clinical outcome after catheter ablation for atrial fibrillation.

BACKGROUND The impact of diffuse atrial fibrosis detected by T1 mapping on the clinical outcome after atrial fibrillation (AF) ablation is unknown. OBJECTIVE This study aimed to validate and assess the impact of post-contrast cardiac magnetic resonance (CMR) imaging atrial T1 mapping on the clinical outcome after catheter ablation for AF. METHODS CMR imaging was performed in 3 groups by using a clinical 1.5-T scanner: controls, patients with paroxysmal AF, and patients with persistent AF. A T1 mapping sequence was used to calculate the post-contrast T1 relaxation time (T1 time) at the interatrial septum as an index of diffuse atrial fibrosis. A subset underwent left atrial endocardial bipolar voltage mapping for electrophysiologic correlation. After AF ablation, patients underwent clinical review and 7-day Holter monitoring at 6-month intervals. RESULTS One hundred thirty-two patients (20 controls, 71 (63%) patients with paroxysmal AF, and 41 (37%) patients with persistent AF) underwent CMR imaging. Post-contrast atrial T1 time was significantly shorter in AF groups (237 ± 42 ms) than in controls (280 ± 37 ms) (P < .001). Post-contrast atrial T1 time correlated with mean septal voltage (R2 = .48; P < .001) and global left atrial voltage (R(2) = .41; P < .001). A diagnosis of AF, AF duration, and left ventricular end-diastolic volume independently predicted shortened post-contrast atrial T1 time. The single procedure success rate was 74% at 12 ± 5 months postablation. Post-contrast atrial T1 time was the only predictor of arrhythmia recurrence in multivariate analysis (P = .015). A post-contrast atrial T1 time of >230 ms was associated with freedom from AF in 85% relative to 62% with a post-contrast atrial T1 time of <230 ms (P = .01). CONCLUSION Post-contrast atrial T1 time as measured using CMR imaging provides an index of atrial fibrosis that correlates with tissue voltage, presence of AF, and clinical outcomes after catheter ablation.

Health-related quality of life 2 years after coronary artery bypass graft surgery.

Background and Research Objective:The primary objective of this longitudinal study was to examine patient-perceived health-related quality of life (HRQOL) and depressive symptoms 2 years after coronary artery bypass graft surgery (CABGS) compared with the results from preoperative and 1 year postoperative data and to compare the 2-year follow-up data with Australian population normative scores. Subjects and Methods:Eighty-seven participants were recruited preoperatively, and their HRQOL was assessed before, 6 weeks, 1 year, and 2 years postoperatively using the Short Form-36 (SF-36) health survey questionnaire and the Beck Depression Inventory. Results and Conclusions:Forty-eight participants completed both questionnaires 2 years after CABGS. Short Form-36 mean scores indicated an overall improvement in all aspects of HRQOL, with a statistically significant improvement in 5 of the SF-36 health domains and in the physical component summary (P ≤ .05). Comparison of 1- and 2-year SF-36 scores revealed a moderate, nonsignificant deterioration in 6 of the health domains and in the physical component summary, whereas Mental Health and the Mental Component Summary showed a moderate, nonsignificant improvement. Two-year postoperative SF-36 scores were similar to normative scores of the Australian population with heart disease. Beck Depression Inventory mean scores were within the normal range (≤9) at 2 years postoperatively and not significantly different from preoperative scores. The research has indicated that most of the participants had significant improvements in their perceived health status 2 years after CABGS and no significant depressive symptoms had been noted; however, it also raises questions as to why there may be some deterioration in health status between 1 and 2 years postoperatively. This has important implications for the planning of nursing care and patient education after CABGS.

A minimal or maximal ablation strategy to achieve pulmonary vein isolation for paroxysmal atrial fibrillation: a prospective multi-centre randomized controlled trial (the Minimax study)

AIMS Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation of atrial fibrillation (AF). The intervenous ridge (IVR) may be incorporated into ablation strategies to achieve PVI; however, randomized trials are lacking. We performed a randomized multi-centre international study to compare the outcomes of (i) circumferential antral PVI (CPVI) alone (minimal) vs. (ii) CPVI with IVR ablation to achieve individual PVI (maximal). METHODS AND RESULTS Two hundred and thirty-four patients with paroxysmal AF underwent CPVI and were randomized to a minimal or maximal ablation strategy. The primary outcome of recurrent atrial arrhythmia was assessed with 7-day Holter monitoring at 6 and 12 months. PVI was achieved in all patients. Radiofrequency ablation time was longer in the maximal group (46.6 ± 14.6 vs. 41.5 ± 13.1 min; P < 0.01), with no significant differences in procedural or fluoroscopy times. At mean follow-up of 17 ± 8 months, there was no difference in freedom from AF after a single procedure between a minimal (70%) and maximal ablation strategy (62%; P = 0.25). In the minimal group, ablation was required on the IVR to achieve electrical isolation in 44%, and was associated with a significant reduction in freedom from AF (57%) compared with the minimal group without IVR ablation (80%; P < 0.01). CONCLUSION There was no statistically significant difference in freedom from AF between a minimal and maximal ablation strategy. Despite attempts to achieve PVI with antral ablation, IVR ablation is commonly required. Patients in whom antral isolation can be achieved without IVR ablation have higher long-term freedom from AF (the Minimax study; ACTRN12610000863033).

Diffuse ventricular fibrosis measured by T₁ mapping on cardiac MRI predicts success of catheter ablation for atrial fibrillation

Background—There is a complex interplay between the atria and ventricles in atrial fibrillation (AF). Cardiac magnetic resonance (CMR) imaging provides detailed tissue characterization, identifying focal ventricular fibrosis with late gadolinium enhancement (ventricular late gadolinium enhancement) and diffuse fibrosis with postcontrast-enhanced T1 mapping. The aim of the present study was to investigate the relationship between postcontrast ventricular T1 relaxation time on CMR and freedom from AF after pulmonary vein isolation. Methods and Results—One hundred three patients undergoing catheter ablation for symptomatic AF (66% paroxysmal AF; age, 58±10 years; left atrial area, 27±7 cm2) underwent preprocedure CMR to determine postcontrast ventricular T1 time. Follow-up included clinical review and 7-day Holter monitors at 6 monthly intervals. All patients underwent successful pulmonary vein isolation. At a mean follow-up of 15±7 months, the single procedure success was 74%. Postcontrast ventricular T1 time was significantly shorter in patients with recurrent AF (366±73 ms) versus patients without AF recurrence (428±90 ms; P=0.002). Univariate predictors of AF recurrence included postcontrast ventricular T1 time, AF type (paroxysmal versus persistent), AF duration, and body mass index. After multivariate analysis, ventricular T1 time (P=0.03) and AF duration (P=0.03) were the only independent predictors. Freedom from AF was present in 84% of patients with a postcontrast ventricular T1 time >380 ms versus 56% in patients with a postcontrast ventricular T1 time <380 ms (P=0.002). Conclusions—A shorter postcontrast ventricular T1 relaxation time on CMR is associated with reduced freedom from AF after catheter ablation. Diffuse ventricular fibrosis as demonstrated by CMR may, in part, explain recurrent AF after AF ablation.

Determining the Optimal Dose of Adenosine for Unmasking Dormant Pulmonary Vein Conduction Following Atrial Fibrillation Ablation: Electrophysiological and Hemodynamic Assessment. DORMANT-AF Study

The significance of adenosine induced dormant pulmonary vein (PV) conduction in atrial fibrillation (AF) ablation remains controversial. The optimal dose of adenosine to determine dormant PV conduction is yet to be systematically explored.

A comparison of the electrophysiologic and electroanatomic characteristics between the right and left atrium in persistent atrial fibrillation: Is the right atrium a window into the left?

The right atrium (RA) is readily accessible; however, it is unclear whether changes in the RA are representative of the LA. We performed detailed biatrial electroanatomic mapping to determine the electrophysiological relationship between the atria.