Severe conduction defects requiring permanent pacemaker implantation in patients with a new-onset left bundle branch block after transcatheter aortic valve implantation.

AIMS: Transcatheter aortic valve implantation (TAVI) is frequently associated with cardiac conduction defects (CCD) requiring permanent pacemaker implantation (PPI). Although new-onset left bundle branch block (LBBB) is often seen, the rate of progression to severe CCD is unclear. We aimed to find clinical and electrocardiographic (ECG) parameters associated with severe CCD requiring PPI in patients with a new-onset LBBB after TAVI and assess its effect on clinical outcome. METHODS AND RESULTS: All consecutive patients undergoing TAVI who developed a new-onset LBBB were retrospectively analysed. We excluded patients with pre-existing bundle branch block or pacemaker. Patients were divided into two groups: with or without PPI after TAVI. We included 155 patients (50% female, 80 ± 7 years), of which 37 (24%) developed CCD requiring PPI, mainly due to a total atrioventricular block (n = 17; 46%). Cardiac conduction defects requiring PPI were associated with the following pre-existing parameters: atrial fibrillation (AF), the use of digoxin, CoreValve implantation, and left heart axis. Furthermore, it was associated with the following post-procedural parameters: left heart axis, lower mean heart rate, and prolonged PQ and QRS times. During follow-up, patients with PPI showed a lower mortality rate (11 vs. 29%, P = 0.03). In patients without PPI, mortality was lower in those with narrower QRS complex and transient LBBB. CONCLUSION: The severity and persistence of a new-onset LBBB after TAVI is associated with mortality. Cardiac conduction defects requiring PPI are associated with prior AF, the use of digoxin, CoreValve implantation, and a left heart axis. In these patients, PPI portends a better prognosis than no PPI.

Tissue characterization of acute lesions during cardiac magnetic resonance-guided ablation of cavo-tricuspid isthmus-dependent atrial flutter: a feasibility study.

AIMS: To characterize acute lesions during cardiac magnetic resonance (CMR)-guided radiofrequency (RF) ablation of cavo-tricuspid isthmus (CTI)-dependent atrial flutter by combining T2-weighted imaging (T2WI), T1 mapping, first-pass perfusion, and late gadolinium enhancement (LGE) imaging. CMR-guided catheter ablation offers a unique opportunity to investigate acute ablation lesions. Until present, studies only used T2WI and LGE CMR to assess acute lesions. METHODS AND RESULTS: Fifteen patients with CTI-dependent atrial flutter scheduled for CMR-guided RF ablation were prospectively enrolled. Directly after achieving bidirectional block of the CTI line, CMR imaging was performed using: T2WI (n = 15), T1 mapping (n = 10), first-pass perfusion (n = 12), and LGE (n = 12) imaging. In case of acute reconnection, additional RF ablation was performed. In all patients, T2WI demonstrated oedema in the ablation region. Right atrial T1 mapping was feasible and could be analysed with a high inter-observer agreement (r = 0.931, ICC 0.921). The increase in T1 values post-ablation was significantly lower in regions showing acute reconnection compared with regions without reconnection [37 ± 90 ms vs. 115 ± 69 ms (P = 0.014), and 3.9 ± 9.0% vs. 11.1 ± 6.8% (P = 0.022)]. Perfusion defects were present in 12/12 patients. The LGE images demonstrated hyper-enhancement with a central area of hypo-enhancement in 12/12 patients. CONCLUSION: Tissue characterization of acute lesions during CMR-guided CTI-dependent atrial flutter ablation demonstrates oedema, perfusion defects, and necrosis with a core of microvascular damage. Right atrial T1 mapping is feasible, and may identify regions of acute reconnection that require additional RF ablation.

2-year outcomes of phased radiofrequency ablation for atrial fibrillation with the second-generation PVAC Gold ablation catheter.

PURPOSE: The second-generation multi-electrode catheter, PVAC Gold, was designed to improve the safe delivery of phased radiofrequency energy using a "single shot" approach for pulmonary vein isolation (PVI), while retaining efficacy. This large registry presents long-term performance in a daily practice setting. METHODS: A total of 1011 patients undergoing first time ablation for atrial fibrillation (AF) using PVAC Gold were included, 639 patients with PVI for paroxysmal AF (PAF PVI) and 372 patients with persistent or long-standing persistent AF, divided into 175 patients receiving PVI only (PersAF PVI) and 197 patients receiving PVI with additional substrate ablation (PersAF PVI +). RESULTS: At 24-month follow-up, single procedure freedom from atrial tachyarrhythmia (ATA) was 58% (368/639) in the PAF PVI group, 44% (77/175) in the PersAF PVI group, and 29% (57/197) in the PersAF PVI + group. Allowing one repeat procedure in 33% of patients, 76%, 65%, and 54% were free from ATA at 24 months, respectively. Pulmonary vein reconnection was observed in 98% of patients with recurrent arrhythmia after PVI. CONCLUSIONS: Although phased RF ablation with PVAC Gold is quick and safe, the efficacy outcomes are modest compared to current mainstream ablation strategies.

Acute success and safety of the second-generation PVAC GOLD phased RF ablation catheter for atrial fibrillation.

PURPOSE: The second-generation multi-electrode catheter, pulmonary vein ablation catheter (PVAC) GOLD, was designed to improve the delivery of phased radiofrequency energy and reduce procedure times using a 'single-shot' approach for pulmonary vein isolation (PVI), while retaining efficacy and safety. This large registry presents acute success rates and safety outcomes in a daily practice setting. METHODS: A total of 1017 patients undergoing first-time ablation for atrial fibrillation (AF) using PVAC GOLD were included, 644 patients with paroxysmal AF and 373 patients with non-paroxysmal AF, divided into 175 patients receiving PVI only and 198 patients receiving PVI with additional substrate modification. RESULTS: High and comparable percentages of successful PVI could be achieved in all groups (98%, 95% and 99%; p = 0.108). The median total procedure time for all groups was 90 min [70-100]. As expected, the total procedure, ablation and fluoroscopy time were significantly longer in the PVI + substrate modification group compared with the PVI-only cases (all p < 0.001), but not between the PVI-only groups (p = 0.306, p = 0.088, p = 0.233, respectively). A total of 44 complications were observed in 43 patients (4.2%). Major complications were seen in 19 patients (1.87%) and non-major procedure-related complications were seen in 25 patients (2.46%). Complications leaving permanent sequelae were rare and occurred in only four patients (0.39%). Complications did not differ between groups (p = 0.199, p = 0.438, p = 0.240 and p = 0.465 respectively). CONCLUSION: PVAC GOLD performs successful PVI, while reducing procedure times and retaining safety for paroxysmal, persistent and long-standing persistent AF. Safety was unaffected by additional substrate modification.

Measure twice, cut once: pitfalls in the diagnosis of supraventricular tachycardia.

In atrioventricular nodal and atrioventricular reentrant tachycardia, the relative timing of atrial and ventricular activation may sometimes be very similar, even during electrophysiological studies, and this may lead to an erroneous diagnosis and inappropriate treatment. As examples, we describe two cases that were recently referred to our hospital for a second opinion and treatment of paroxysmal supraventricular tachycardia. In both, the original diagnosis of the referring centres was commontype atrioventricular nodal reentrant tachycardia. Catheter ablation in those centres was unsuccessful. During our electrophysiological studies, however, an atrioventricular reentrant tachycardia was demonstrated, using a concealed accessory pathway for retrograde conduction in both patients. The accessory atrioventricular connection was successfully ablated and on follow-up both patients remained free of symptoms without medication. These findings illustrate the importance of complete electrophysiological analysis even for apparently simple supraventricular arrhythmias. (Neth Heart J 2010;18:78-84.).