Half-normal saline versus normal saline for irrigation of open-irrigated radiofrequency catheters in atrial fibrillation ablation.

BACKGROUND: The creation of effective and permanent lesions is a crucial factor in determining the success rate of atrial fibrillation (AF) ablation. By increasing the efficacy of radiofrequency (RF) energy-mediated lesion formation, half-normal saline (HNS) as an irrigant for open-irrigated ablation catheters has the potential to reduce procedural times and improve acute and long-term outcomes. METHODS: This is a double-blind randomized clinical trial of 99 patients undergoing first-time RF catheter ablation for AF. Patients enrolled were randomly assigned in a 1:1 fashion to perform ablation using HNS or normal saline (NS) as an irrigant for the ablation catheter. RESULTS: The use of HNS is associated with shorter RF times (26 vs. 33 min; p = .02) with comparable procedure times (104 vs. 104 min). The rate of acute pulmonary vein reconnections (16% vs. 18%) was comparable, with a median of 1 vein reconnection in the HNS arm versus 2 in the NS arm. There was no difference in procedure-related complications, including the incidence of postprocedural hyponatremia when using HNS. Over the 1-year follow-up, there is no significant difference between the HNS and NS with respect to the recurrence of any atrial arrhythmia (off antiarrhythmic drugs [AAD]: 47% vs. 52%; hazard ratio [HR]: 1.17, 95% confidence interval [CI]: 0.66-2.06; off/on AAD: 66% vs. 66%, HR: 1.06, 95% CI: 0.53-2.12), with a potential benefit of using HNS when considering the paroxysmal AF cohort (on/off AAD 73% vs. 62%, HR: 0.72, 95% CI: 0.19-2.70). CONCLUSIONS: In a mixed cohort of patients undergoing first-time AF ablation, irrigation of open-irrigated RF ablation catheters with HNS is associated with shorter RF times, with a comparably low rate of procedure-related complications. In the long term, there is no significant difference with respect to the recurrence of any atrial arrhythmia. Larger studies with a more homogeneous population are necessary to determine whether HNS improves clinical outcomes.

Ablation of perimitral flutter following catheter ablation of atrial fibrillation: impact on outcomes from a randomized study (PROPOSE).

INTRODUCTION: Patients with previous ablation for atrial fibrillation (AF) may experience recurrence of perimitral flutter (PMFL). These arrhythmias are usually triggered from sources that may also induce AF. This study aims at determining whether ablation of triggers or completing mitral valve isthmus (MVI) block prevents more arrhythmia recurrences. METHODS AND RESULTS: Sixty-five patients with recurrent PMFL after initial ablation of long standing persistent AF were included in this study. Thirty-two patients were randomized to MVI ablation only (Group 1) and 33 were randomized to cardioversion and repeat pulmonary vein (PV) isolation plus ablation of non-PV triggers (Group 2). MVI bidirectional block was achieved in all but 1 patient from Group 1. In Group 2, reconnection of 17 PVs was detected in 14 patients (42%). With isoproterenol challenge, 44 non-PV trigger sites were identified in 28 patients (85%, 1.57 sites per patient). At 18-month follow-up, 27 patients (84%) from Group 1 had recurrent atrial tachyarrhythmias, of whom 15 remained on antiarrhythmic drug (AAD); however, 28 patients from Group 2 (85%, P < 0.0001 vs Group 1) were free from arrhythmia off AAD. The ablation strategy used in Group 2 was associated with a lower risk of recurrence (hazard ratio = 0.10, 95% CI 0.04-0.28, P < 0.001) and an improved arrhythmia-free survival (log rank P < 0.0001). CONCLUSION: In patients presenting with PMFL after ablation for longstanding persistent AF, MVI block had limited impact on arrhythmia recurrence. On the other hand, elimination of all PV and non-PV triggers achieved higher freedom from atrial arrhythmias at follow-up.

Positioning of left ventricular pacing lead guided by intracardiac echocardiography with vector velocity imaging during cardiac resynchronization therapy procedure.

INTRODUCTION: Intraoperative modality for "real-time" left ventricular (LV) dyssynchrony quantification and optimal resynchronization is not established. This study determined the feasibility, safety, and efficacy of intracardiac echocardiography (ICE), coupled with vector velocity imaging (VVI), to evaluate LV dyssynchrony and to guide LV lead placement at the time of cardiac resynchronization therapy (CRT) implant. METHODS: One hundred and four consecutive heart failure patients undergoing ICE-guided (Group 1, N = 50) or conventional (Group 2, N = 54) CRT implant were included in the study. For Group 1 patients, LV dyssynchrony and resynchronization were evaluated by VVI including visual algorithms and the maximum differences in time-to-peak (MD-TTP) radial strain. Based on the findings, the final LV lead site was determined and optimal resynchronization was achieved. CRT responders were defined using standard criteria 6 months after implantation. RESULTS: Both groups underwent CRT implant with no complications. In Group 1, intraprocedural optimal resynchronization by VVI including visual algorithms and MD-TTP was a predictor discriminating CRT response with a sensitivity of 95% and specificity of 89%. Use of ICE/VVI increased number of and predicted CRT responders (82% in Group 1 vs 63% in Group 2; OR = 2.68, 95% CI 1.08-6.65, P = 0.03). CONCLUSION: ICE can be safely performed during CRT implantation. "Real-time" VVI appears to be helpful in determining the final LV lead position and pacing mode that allow better intraprocedural resynchronization. VVI-optimized acute resynchronization predicts CRT response and this approach is associated with higher number of CRT responders.

Left atrial appendage: an underrecognized trigger site of atrial fibrillation.

BACKGROUND: Together with pulmonary veins, many extrapulmonary vein areas may be the source of initiation and maintenance of atrial fibrillation. The left atrial appendage (LAA) is an underestimated site of initiation of atrial fibrillation. Here, we report the prevalence of triggers from the LAA and the best strategy for successful ablation. METHODS AND RESULTS: Nine hundred eighty-seven consecutive patients (29% paroxysmal, 71% nonparoxysmal) undergoing redo catheter ablation for atrial fibrillation were enrolled. Two hundred sixty-six patients (27%) showed firing from the LAA and became the study population. In 86 of 987 patients (8.7%; 5 paroxysmal, 81 nonparoxysmal), the LAA was found to be the only source of arrhythmia with no pulmonary veins or other extrapulmonary vein site reconnection. Ablation was performed either with focal lesion (n=56; group 2) or to achieve LAA isolation by placement of the circular catheter at the ostium of the LAA guided by intracardiac echocardiography (167 patients; group 3). In the remaining patients, LAA firing was not ablated (n=43; group 1). At the 12+/-3-month follow-up, 32 patients (74%) in group 1 had recurrence compared with 38 (68%) in group 2 and 25 (15%) in group 3 (P<0.001). CONCLUSIONS: The LAA appears to be responsible for arrhythmias in 27% of patients presenting for repeat procedures. Isolation of the LAA could achieve freedom from atrial fibrillation in patients presenting for a repeat procedure when arrhythmias initiating from this structure are demonstrated.

Locating the right phrenic nerve by imaging the right pericardiophrenic artery with computerized tomographic angiography: implications for balloon-based procedures.

BACKGROUND: Phrenic nerve (PN) injury, a known complication of radiofrequency (RF) catheter ablation of atrial fibrillation (AF), has been more commonly reported with balloon-based pulmonary vein isolation. OBJECTIVE: We present a novel approach to locating the PN and predicting patients at higher risk of this complication. METHODS: The study included 2 groups of patients. In the first group of 71 patients, computerized tomographic angiography (CTA) with 3-dimensional reconstruction of the left atrium (LA) was obtained prior to an RF ablation procedure. The location of the right pericardiophrenic artery (RPA) was identified on the axial CTA images, and the artery distance to the right superior pulmonary vein (RSPV) ostium was measured in the 3-dimensional image. During ablation, the location of the right PN was identified by pacing maneuvers. The distance to the ostium of the RSPV was measured by venography and compared with the CTA artery measurement. In the second group, CTA imaging from 37 subjects who were enrolled in 3 investigational balloon ablation trials were analyzed using the same PN location technique and compared against the clinical outcomes. In this analysis, the CTA segmentation and PN location was performed in a blinded fashion as to any clinical evidence of PN injury. RESULTS: The mean measurement difference between PN capture and imaged RPA was 0.8 mm (P = .539). In all cases, the imaged RPA could reliably identify the approximate location of the right PN (R-square 0.984, P < .001). Moreover, this analysis suggests that a PN location within 10 mm of the RSPV poses a higher risk of PN injury using these balloon ablation devices. CONCLUSION: Imaging the right pericardiophrenic artery can reliably locate the right phrenic nerve. This technique might identify anatomy more vulnerable to phrenic nerve injury using balloon-based ablation systems.

The impact of statins and renin-angiotensin-aldosterone system blockers on pulmonary vein antrum isolation outcomes in post-menopausal females.

AIMS: To assess whether treatment with statins or renin-angiotensin-aldosterone system (RAAS) inhibitors as potential procedural 'augmenting agents' improved atrial fibrillation (AF) catheter ablation recurrence rates in post-menopausal females (PMFS). METHODS AND RESULTS: Five hundred and eighteen consecutive female patients had undergone AF catheter ablation from January 2005 to May 2008. Post-menopausal females were selected and procedure outcomes were compared between cohorts of PMFS treated with statins or RAAS inhibitors to untreated PMFS. Out of 408 PMFS, 36 (8.8%) were treated with a combination of RAAS inhibitors and statins, thus were excluded leaving a total of 372 (91.2%) patients in the study. Out of 372 patients, 111 (29.8%) were on statins (Group 1), 59 (15.9%) on RAAS inhibitors (Group 2), and 202 (54.3%) without RAAS inhibitors or statins [(Group 3) control population]. Over a mean follow-up time of 24 +/- 8.3 (median 25) months, 78 (70.6%) in Group 1, 38 (65.4%) in Group 2, and 139 (68.8%) in Group 3 had procedural success. Statin or RAAS inhibitor use did not predict lower recurrence rates [hazard ratio (HR): 1.26, P = 0.282 and HR: 1.14, P = 0.728, respectively]. When compared with controls, no difference in the cumulative incidence of recurrence was found with statin or RAAS inhibitors use (P = 0.385 and P = 0.761, respectively). CONCLUSION: Treatment with statins or RAAS inhibitors did not improve catheter ablation success rates among PMFS. Thereby, from a clinical standpoint, PMFS should not be started on these treatments as a procedural 'augmenting agent' at this time.

Long-term functional and neurocognitive recovery in patients who had an acute cerebrovascular event secondary to catheter ablation for atrial fibrillation.

INTRODUCTION: Cerebral thromboembolic event (CTE) is a possible complication of pulmonary vein antrum isolation (PVAI). The objective of this study was to report long-term functional and neurocognitive recovery in patients who had a CTE during or within 48 hours of catheter ablation. METHODS AND RESULTS: We screened 3,060 patients who underwent PVAI between January 2000 and June 2007. Out the 3,060 patients, 26 patients (0.8%) (61 +/- 8 years, 88% males) had a CTE during or within 48 hours of the procedure. We followed these 26 patients (study group) over time and assessed their functional and neurocognitive recovery status. No preferential vascular territory for the site of obstruction was found; right anterior circulation-5 patients (26%), left anterior circulation-5 patients (26%), posterior circulation-3 patients (16%), and 2 or more territories-6 patients (32%), (P-value = 0.8). The average international normalized ratio at the time of CTE was 1.33 +/- 0.4. Two patients died during the study period. At the end of 38.4 +/- 24 months follow-up, most surviving patients had complete neurocognitive and functional recovery irrespective of the severity of periprocedural stroke. CONCLUSIONS: Periprocedural stroke in the setting of catheter ablation for atrial fibrillation is relatively rare. When it occurs, complete functional and neurocognitive recovery over time is the likely outcome for most patients.

Outcomes and complications of catheter ablation for atrial fibrillation in females.

BACKGROUND: Most atrial fibrillation (AF) ablation studies have consisted predominantly of males; accordingly, there is a paucity of information on the safety and efficacy of catheter ablation in a large cohort of female AF patients. OBJECTIVE: The purpose of this study was to evaluate catheter ablation for AF in female patients. METHODS: From January 2005 to May 2008, 3265 females underwent pulmonary vein antrum isolation. Success rates, patient profiles, and complications were collected. RESULTS: Approximately 16% of our population was female (P <.001). Females were older (59 +/- 13 vs. 56 +/- 19 years; P <.01) and had a lower prevalence of paroxysmal atrial fibrillation (PAF; 46% vs. 55%; P <.001). Females failed more antiarrhythmics (4 +/- 1 vs. 2 +/- 3; P = .04) and were referred later for catheter ablation (6.51 +/- 7 vs. 4.85 +/- 6.5 years; P = .02) than males. More females failed ablation (31.5% vs. 22.5%; P = .001) and had nonantral sites of firing than males (P <.001). Female patients had 11 (2.1%) hematomas versus 27 (0.9%) in males. CONCLUSIONS: Five times as many males underwent catheter ablation than females. Females failed more ablations possibly because of a higher prevalence of nonantral firing, non-PAF, and longer history of AF. Females had more bleeding complications than males.

Omega-3 polyunsaturated Fatty Acid supplementation reduced atrial fibrillation recurrence after pulmonary vein antrum isolation.

OBJECTIVE: To assess if patients treated with omega-3(n-3) polyunsaturated fatty acids (PUFAS) had lower procedural failure rates compared to an untreated population. METHODS AND RESULTS: From January 2004 to 2007, 1500 PVAI patients underwent catheter ablation. Two hundred and eighty five (19%) patients were treated with PUFAs. These patients were matched in a nested case controlled analysis. After matching, there were 129 patients in the PUFA group and 129 in the control group. Thirty-five (27.1%) patients in the study group had early recurrence vs. 57 (44.1%) in the control group p-value< 0.0001. Twenty-nine (23.2%) patients in the PUFA group vs. 41 (31.7%) in the non-PUFA group had procedural failure (p-value < 0.003). There were no significant differences in complications in the PUFA and non-PUFA groups. CONCLUSION: Patients treated with PUFAs had lower incidences of early recurrence and procedural failure compared to an untreated population.

Complications of pacemakers and defibrillators in the elderly.

Within the United States, the elderly population is projected to increase 126% by 2050, making those over the age of 65 the most rapidly growing segment in the population. Permanent pacemakers and defibrillators are important therapies with expanding indications for their use, and older persons constitute the majority of recipients of these devices. Recognizing complications associated with these cardiac devices is essential in caring for patients with them. Complications can be related to the implantation procedure and are most commonly lead dislodgement, pneumothorax, lead perforation, hematoma, and infection. Intrinsic device programming can also result in complications such as pacemaker syndrome, pacemaker-mediated tachycardia, and inappropriate shocks. Extrinsic factors, such as electromagnetic interference and physically manipulating the device, can also result in problems. Recent work suggests that older age, by itself, is not associated with a significant increase in the complication rates from these devices and should not preclude their use.

Strategies for the safe magnetic resonance imaging of pacemaker-dependent patients.

OBJECTIVE: To determine if strategies used to safely scan nonpacemaker-dependent patients could be applied to facilitate safe MRI of pacemaker-dependent patients. INTERVENTIONS: Ten pacemaker-dependent patients underwent a total of 11 MRI scans of the head and neck. Screening, reprogramming VOO or DOO at 60 ppm, and monitoring strategies were used to facilitate MRI. A transmit-receive coil was used and MRI pulse sequences were modified to limit the whole-body specific absorption rate (SAR). RESULTS: All scans proceeded uneventfully. No difficulties in post-MRI telemetry or interrogation were seen and no post-MRI programming changes were noted. No patient experienced arrhythmia or symptoms during or immediately after MRI. Battery status remained unchanged. No patient experienced post-MRI change in sensing thresholds. Three patients showed no change in the atrial or ventricular pacing thresholds when the pre-MRI values were compared to the immediate post-MRI values and the 3-month follow-up values. All other patients showed a rise or fall of 0.5 V in their chamber threshold values when the pre-MRI, post-MRI, and 3-month follow-up values were compared. More patients showed a fall in their pacing thresholds than a rise post-MRI. CONCLUSION: While clearly a higher risk group, like nonpacemaker-dependent patients, MRI might be performed in pacemaker-dependent patients if appropriate pacemaker reprogramming, patient monitoring, and MRI scanning techniques are implemented.