High-Frequency Low-Tidal Volume Ventilation Improves Long-Term Outcomes in AF Ablation: A Multicenter Prospective Study

BACKGROUND

High-frequency, low-tidal-volume (HFLTV) ventilation is a safe and simple strategy to improve catheter stability and first-pass isolation during pulmonary vein (PV) isolation. However, the impact of this technique on long-term clinical outcomes has not been determined.

OBJECTIVES

This study sought to assess acute and long-term outcomes of HFLTV ventilation compared with standard ventilation (SV) during radiofrequency (RF) ablation of paroxysmal atrial fibrillation (PAF).

METHODS

In this prospective multicenter registry (REAL-AF), patients undergoing PAF ablation using either HFLTV or SV were included. The primary outcome was freedom from all-atrial arrhythmia at 12 months. Secondary outcomes included procedural characteristics, AF-related symptoms, and hospitalizations at 12 months.

RESULTS

A total of 661 patients were included. Compared with those in the SV group, patients in the HFLTV group had shorter procedural (66 [IQR: 51-88] minutes vs 80 [IQR: 61-110] minutes; P < 0.001), total RF (13.5 [IQR: 10-19] minutes vs 19.9 [IQR: 14.7-26.9] minutes; P < 0.001), and PV RF (11.1 [IQR: 8.8-14] minutes vs 15.3 [IQR: 12.4-20.4] minutes; P < 0.001) times. First-pass PV isolation was higher in the HFLTV group (66.6% vs 63.8%; P = 0.036). At 12 months, 185 of 216 (85.6%) in the HFLTV group were free from all-atrial arrhythmia, compared with 353 of 445 (79.3%) patients in the SV group (P = 0.041). HLTV was associated with a 6.3% absolute reduction in all-atrial arrhythmia recurrence, lower rate of AF-related symptoms (12.5% vs 18.9%; P = 0.046), and hospitalizations (1.4% vs 4.7%; P = 0.043). There was no significant difference in the rate of complications.

CONCLUSIONS

HFLTV ventilation during catheter ablation of PAF improved freedom from all-atrial arrhythmia recurrence, AF-related symptoms, and AF-related hospitalizations with shorter procedural times.

Paroxysmal Atrioventricular Block: A Rare Cause of Cardiac Arrest

Paroxysmal atrioventricular block (PAVB) is characterized by a sudden and unanticipated repetitive block of atrial impulses to the ventricles. It is often triggered by supraventricular and ventricular ectopic beats in patients with diseased His-Purkinje system. We present the case of a 69-year-old woman with a history of fascicular block who was admitted with gastrointestinal bleeding. Her hospital course was complicated by cardiac arrest. At the time of the loss of consciousness, telemetry tracings showed sudden onset high-grade second-degree atrioventricular (AV) block with a delayed escape rhythm resulting in a prolonged pause. Adult cardiac life support was necessary along with transvenous pacing until she ultimately underwent the placement of a permanent pacemaker. Thorough evaluation of electrocardiograms (EKGs) and telemetry allowed for accurate diagnoses and appropriate treatment of cardiac arrest secondary to paroxysmal AV block.

Practice Patterns of Operators Participating in the Real-World Experience of Catheter Ablation for Treatment of Symptomatic Paroxysmal and Persistent Atrial Fibrillation (REAL-AF) Registry

BACKGROUND

The Real-World Experience of Catheter Ablation for Treatment of Symptomatic Paroxysmal and Persistent Atrial Fibrillation (REAL-AF) is a multicenter prospective registry of atrial fibrillation (AF) ablation. We sought to describe the baseline workflows of REAL-AF operators.

METHODS

REAL-AF enrolls high volume minimum fluoroscopy radiofrequency ablators. A 150 item questionnaire was administered to participating operators. Responses were analyzed using standard methods.

RESULTS

Forty-two respondents had a mean 178.2 ± 89.2 yearly AF ablations, with 42.4 ± 11.9% being paroxysmal (PAF). Most operators performed ablation with uninterrupted or minimally interrupted anticoagulation (66.7% and 28.6%). Left atrial appendage (LAA) thrombus was most commonly ruled out with transesophageal echocardiography (33.3% and 42.9% for PAF and persistent AF). Consistent with registry design, radiofrequency energy (92.1% ± 18.8% of cases) and zero fluoroscopy ablation (73.8% goal 0 fluoroscopy) were common. The majority of operators relied on index-guided ablation (90.5%); Mean Visitag surpoint targets were higher anteriorly vs posteriorly (508.3 ± 49.8 vs 392.3 ± 37.0, p < 0.01), but power was similar. There was considerable heterogeneity related to gaps in current knowledge, such as lesion delivery targets and sites of extra-pulmonary vein ablation (most common was the posterior wall followed by the roof). Peri-procedural risk factor management of obesity, hypertension, and sleep apnea was common. There was a mean of 3.0 ± 1.2 follow-up visits at 12 months.

CONCLUSIONS

REAL-AF operators were high volume low fluoroscopy "real world" operators with good follow-up and adherence to known best-practices. There was disagreement related to knowledge gaps in guidelines.

Bayesian network meta-analysis comparing cryoablation, radiofrequency ablation, and antiarrhythmic drugs as initial therapies for atrial fibrillation

BACKGROUND

Antiarrhythmic drugs (AADs) and catheter ablation are first line treatments of paroxysmal atrial fibrillation (PAF), however, there exists a paucity of data regarding the potential benefit of different catheter ablation technologies versus AADs as an early rhythm strategy.

OBJECTIVE

To assess the safety and efficacy of cryoablation versus radiofrequency ablation (RFA) versus AADs as a first line therapy of PAF.

METHODS

MEDLINE, Embase, Scopus and CENTRAL were searched to retrieve randomized clinical trials (RCTs) comparing cryoablation, RFA or AADs to one another as first line therapies for atrial fibrillation (AF). The primary outcome was overall freedom from arrhythmia recurrence (AF, atrial flutter [AFL], atrial tachycardia). Secondary outcomes included freedom from symptomatic arrhythmia recurrence, hospitalization, and serious adverse events. A random-effects Bayesian network meta-analysis was used to calculate odds ratios (OR) and 95% credible intervals (CrI).

RESULTS

Six RCTs (N = 1212) met the inclusion criteria (605 AADs, 365 Cryoablation, and 245 RFA). Compared with AADs, overall recurrence was reduced with RFA (OR: 0.31; 95% CrI: 0.10-0.71) and cryoablation (OR: 0.39; 95% CrI: 0.16-1.00). Comparing ablation (cryoablation and RFA) with AADs in respect to freedom from symptomatic AF recurrence, neither cryoablation (OR: 0.35; 95% CrI: 0.06-1.96) nor RFA (OR: 0.34; 95% CrI: 0.07-1.27) resulted in statistically significant reductions individually compared to AADs, though pooled ablation with both technologies showed lower odds of arrhythmia recurrence (OR: 0.35; 95% CrI: 0.13-0.79). In terms of serious adverse events rates, neither cryoablation (OR: 0.77; 95% CrI: 0.44-1.39) nor RFA (OR: 1.45; 95% CrI: 0.67-3.23) were significantly different to AADs. RFA resulted in a statistically significant reduction in hospitalizations compared to AAD (OR: 0.08; 95% CrI: 0.01-0.99), whereas cryoablation did not (OR: 0.77; 95% CrI: 0.44-1.39). The surface under the cumulative ranking curve showed RFA to be the most effective treatment at reducing overall rates of recurrence, symptomatic recurrence and hospitalizations; whereas cryoablation was most likely to reduce serious adverse events.

CONCLUSION

Cryoablation and RFA are both effective and safe first line therapies for AF compared to AADs, with RFA being the most effective at reducing recurrences.

Safety and Efficacy of Minimal- versus Zero-fluoroscopy Radiofrequency Catheter Ablation for Atrial Fibrillation: A Multicenter, Prospective Study

Radiofrequency catheter ablation (CA) is an effective treatment for atrial fibrillation (AF) that traditionally requires fluoroscopic imaging to guide catheter movement and positioning. However, advances in electroanatomic mapping (EAM) technology and intracardiac echocardiography (ICE) have reduced procedural reliance on fluoroscopy. We conducted a prospective registry study of 162 patients enrolled at five centers proficient in high-volume, minimal-fluoroscopy CA between March 2016 and March 2018 for the CA of symptomatic, drug-refractory paroxysmal, or persistent AF that sought to assess the safety and efficacy of minimal- versus zero-fluoroscopy AF CA. We evaluated procedural details, acute procedural outcomes and complications, and one-year follow-up data. All operators used an EAM system (CARTO^®; Biosense Webster, Irvine, CA, USA) and ICE. Ultimately, two patients did not pursue CA postenrollment. A total of 104 (66%) patients had paroxysmal AF with a mean ejection fraction of 58% ± 9%. Twenty-six (16.3%) patients were scheduled for repeat ablation. A total of 100 (63%) procedures were performed with zero fluoroscopy. The mean fluoroscopy time in the minimal-fluoroscopy group was 1.7 minutes ± 2.8 minutes. Further, the mean procedure duration was 192 minutes ± 37 minutes in the zero-fluoroscopy group and 201 minutes ± 29 minutes in the minimal-fluoroscopy group (p = 0.96). Pulmonary vein isolation was achieved in 153 patients (100%), with an acute procedural complication rate of 1.8%. One-year follow-up data were available for 152 (95%) patients with a mean follow-up time of 11.3 months ± 1.8 months. A total of 118 (76%) patients remained free from arrhythmia for up to 12 months, with no difference between the minimal- and zero-fluoroscopy cohorts (p = 0.18).

Cardiac Sarcoidosis Causing Ventricular Tachycardia After Myocardial Infarction: A Shocking Diagnosis

Scar-mediated ventricular tachycardia (VT) commonly results from ischemic heart disease. We present a case of recurrent VT, which was initially attributed to ischemic disease; however, the scar location pointed to an alternate pathology. This case demonstrates the utility of multimodality imaging in diagnosing sarcoidosis as a cause of VT. (Level of Difficulty: Intermediate.)

Safety and efficacy of zero fluoroscopy transseptal puncture with different approaches

INTRODUCTION

Atrial fibrillation (AF) ablation requires access to the left atrium (LA) via transseptal puncture (TP). TP is traditionally performed with fluoroscopic guidance. Use of intracardiac echocardiography (ICE) and three-dimensional mapping allows for zero fluoroscopy TP.

OBJECTIVE

To demonstrate safety and efficacy of zero fluoroscopy TP using multiple procedural approaches.

METHODS

Patients undergoing AF ablation between January 2015 and November 2017 at five institutions were included. ICE and three-dimensional mapping were used for sheath positioning and TP. Variable technical approaches were used across centers including placement of J wire in the superior vena cava with ICE guidance followed by dragging down the transseptal sheath into the interatrial septum, or guiding the transseptal sheath directly to the interatrial septum by localizing the ablation catheter with three-dimensional mapping and replacing it with the transseptal needle once in position. In patients with pacemaker/implantable cardiac defibrillator leads, pre-/poststudy device interrogation was performed.

RESULTS

A total of 747 TPs were performed (646 patients, age 63.1 ± 13.1, 67.5% male, LA volume index 34.5 ± 15.8 mL/m² , ejection fraction 57.7 ± 10.9%) with 100% success. No punctures required fluoroscopy. Two pericardial effusions, two pericardial tamponades requiring pericardiocentesis, and one transient ischemic attack were observed during the overall ablation procedure, with a total complication rate of 0.7%. There were no other periprocedural complications related to TP, including intrathoracic bleeding, stroke, or death both immediately following TP and within 30 days of the procedure. In patients with intracardiac devices, no device-related complications were observed.

CONCLUSION

TP can be safely and effectively performed without the need for fluoroscopy.

Use of a noninvasive continuous monitoring device in the management of atrial fibrillation: a pilot study

Background

Outpatient ambulatory cardiac rhythm monitoring is a routine part of the management of patients with paroxysmal atrial fibrillation (AF). Current systems are limited by patient convenience and practicality.

Methods

We compared the Zio® Patch, a single-use, noninvasive waterproof long-term continuous monitoring patch, with a 24-hour Holter monitor in 74 consecutive patients with paroxysmal AF referred for Holter monitoring for detection of arrhythmias.

Results

The Zio® Patch was well tolerated, with a mean monitoring period of 10.8 ± 2.8 days (range 4–14 days). Over a 24-hour period, there was excellent agreement between the Zio® Patch and Holter for identifying AF events and estimating AF burden. Although there was no difference in AF burden estimated by the Zio® Patch and the Holter monitor, AF events were identified in 18 additional individuals, and the documented pattern of AF (persistent or paroxysmal) changed in 21 patients after Zio® Patch monitoring. Other clinically relevant cardiac events recorded on the Zio® Patch after the first 24 hours of monitoring, including symptomatic ventricular pauses, prompted referrals for pacemaker placement or changes in medications. As a result of the findings from the Zio® Patch, 28.4% of patients had a change in their clinical management.

Conclusions

The Zio® Patch was well tolerated, and allowed significantly longer continuous monitoring than a Holter, resulting in an improvement in clinical accuracy, the detection of potentially malignant arrhythmias, and a meaningful change in clinical management. Further studies are necessary to examine the long-term impact of the use of the Zio® Patch in AF management.

Effects of Left Ventricular Assist Device Therapy on Ventricular Arrhythmias

OBJECTIVES

In a retrospective study, we sought to evaluate the effect of left ventricular assist device (LVAD) therapy on ventricular tachyarrhythmias in patients with advanced congestive heart failure.

BACKGROUND

Despite the increasing use of LVAD as a bridge to cardiac transplantation, our knowledge regarding its effect on ventricular arrhythmias is currently limited to small series. Little is known about the prevalence, predictors, and clinical consequences of ventricular arrhythmias in LVAD recipients.

METHODS

We reviewed the pre- and post-LVAD course of the last 100 consecutive adult patients to receive a HeartMate LVAD (Thoratec Laboratories Corp., Pleasanton, California) at our institution. All ventricular arrhythmias sustained for at least 30 s or requiring defibrillation were analyzed. All documented pre- and post-LVAD sustained ventricular arrhythmias were classified either as monomorphic ventricular tachycardia (MVT) or polymorphic ventricular tachycardia (PVT)/ventricular fibrillation (VF).

RESULTS

Our population had an average age of 51 years, had predominately ischemic cardiomyopathy (63%), and a mean left ventricular ejection fraction of 20 +/- 10%. New-onset MVT was observed in 18 patients who did not have MVT before LVAD placement. After LVAD, new-onset MVT was 4.5 times more likely than elimination of previously present MVT (p = 0.001), whereas the effect of LVAD on incidence of PVT/VF was not significant. In a multivariate Cox proportional hazards regression analysis, serum electrolyte abnormality was an independent predictor of post-LVAD ventricular arrhythmias. Preoperative MVT did not predict postoperative MVT.

CONCLUSIONS

After LVAD placement, there is a significant rise in the incidence of de novo MVT. By contrast, the incidence of PVT/VF was unaffected by LVAD placement.

Topotecan is anti-angiogenic in experimental hepatoblastoma

BACKGROUND

Advanced hepatoblastoma often is lethal despite current therapies, yet development of novel approaches has been hampered by the lack of biologically relevant models. One new strategy selectively targets endothelium rather than tumor cells using frequently administered, low-dose ("metronome") chemotherapy. Metronome topotecan has antiangiogenic activity in some experimental tumors. The authors developed a xenograft model of human hepatoblastoma to test the effect of metronome topotecan in this system.

METHODS

Xenografts resulted from intrarenal injection of cultured human hepatoblastoma cells in athymic mice. Topotecan (0.36 mg/kg/dose) or vehicle was injected intraperitoneally 5 times per week. At week 6, 10 control/treated mice were killed, and remaining animals were maintained without treatment until week 8. Tumor weights were compared by Kruskal-Wallis analysis, and vascular alterations were ascertained by specific immunostaining.

RESULTS

Metronome topotecan affected tumor weights in a delayed fashion: weights were diminished significantly only at 8 weeks (treated v control: 6 weeks, 0.59 g v 82 g, P value, not significant; 8 weeks, 1.13 g v 3.82; P <.02). Decreased vascularity and increased endothelial cell apoptosis were observed in treated xenografts.

CONCLUSIONS

Metronome topotecan inhibits growth and neovascularization in experimental hepatoblastoma. The durability of this effect is novel and has not been observed in other xenograft tumor models. Cytotoxic targeting of endothelial cells may hold particular promise for therapy of children with advanced hepatoblastoma. .