Dynamic ventricular overdrive stimulation in atrial fibrillation: effects on ventricular rate irregularity, ventricular pacing, and fusion beats.

AIMS: In pacemaker patients with preserved atrio-ventricular (AV) conduction, atrial fibrillation (AF) can lead to symptomatic ventricular rate irregularity and loss of ventricular stimulation. We tested if dynamic ventricular overdrive (DVO) as a potentially pacemaker-integrated algorithm could improve both aspects. METHODS AND RESULTS: Different settings of DVO and ventricular-ventricular-inhibited-pacing (VVI) with different base rates were tested in two consecutive phases during electrophysiological studies for standard indications. Mean heart rate (HR), HR irregularity and percentage of ventricular pacing were evaluated. A fusion index (FI) indicative of the proportion of fusion beats was calculated for each stimulation protocol. Dynamic ventricular overdrive from the right ventricular apex was acutely applied in 38 patients (11 females, mean age 62.1 ± 11.5 years) with sustained AF and preserved AV conduction. Dynamic ventricular overdrive at LOW/MEDIUM setting increased the amount of ventricular pacing compared with VVI pacing at 60, 70, and 80 beats per minute (bpm; to 81/85% from 11, 25, and 47%, respectively; P < 0.05). It also resulted in a maximum decrease in interval differences (to 48 ± 18 ms from 149 ± 28, 117 ± 38, and 95 ± 46 ms, respectively; P < 0.05) and fusion (to 0.13 from 0.41, 0.42, and 0.36, respectively; P < 0.05) compared with VVI pacing at 60, 70, and 80 bpm. However, the application of DVO resulted in a significant increase in HR compared with intrinsic rhythm and VVI pacing at 80 bpm (to 97 bpm from 89 and 94 bpm, respectively; P < 0.05). CONCLUSION: Dynamic ventricular overdrive decreases HR irregularity and increases ventricular pacing rate compared with VVI pacing at fixed elevated base rates and spontaneous rhythm. Fusion index might help to refine information on pacing percentages provided by device counters.

Left atrial lesion formation and volume overload by open irrigation ablation technology during pulmonary vein antrum isolation: acute effects on cardiac hemodynamics.

PURPOSE: Our goal was to evaluate acute effects of left atrial lesion formation and volume overload on hemodynamics during pulmonary vein antrum isolation (PVAI) as it might be a potential cause of acute pulmonary edema. METHODS: In consecutive patients presenting for PVAI, open irrigation ablation was performed (50 W, 48°C, 15 s lesion duration, saline flow rate 30 mL/min). Blood samples were drawn from the left atrium and the pulmonary artery immediately before and 30 min after PVAI. The cardiac output (CO) and stroke volume (SV) were calculated by the method of Fick. RESULTS: We included 61 (27 female, 61 ± 11 years) patients suffering from paroxysmal (px; 33) or persistent (per; 28) atrial fibrillation (AF) in this study. A total of 2,917 ± 242 mL of volume was infused (2,651 ± 223 mL pxAF vs. 3,184 ± 255 mL perAF, (p < 0.01)). Total ablation time was 60 ± 7 min (52 ± 7 min in pxAF vs. 69 ± 8 min in perAF; (p < 0.001)). CO increased from 5.2 ± 1.3 to 6.2 ± 1.5 L/min (p < 0.001) during PVAI (5.7 ± 1.3 to 6.5 ± 1.7 L/min in pxAF; (p < 0.002) and 4.8 ± 1.1 to 5.9 ± 1.2 L/min in perAF; (p < 0.001)). SV increased from 74 ± 24 to 83 ± 21 mL (p < 0.005) during PVAI, and subgroups showed an increase of 82 ± 23 to 88 ± 22 mL in pxAF (p < 0.009) and 62 ± 21 to 76 ± 16 mL in perAF (p < 0.009). CONCLUSIONS: From our preliminary experience, left atrial scarring and volume overload during PVAI do not seem to impact negatively hemodynamics. On the contrary, an improvement in cardiac output was documented acutely independent of type of AF.

Three-dimensional coronary sinus reconstruction-guided left ventricular lead implantation based on intraprocedural rotational angiography: a novel imaging modality in cardiac resynchronization device implantation.

AIMS: Rotational angiography (RA) of the coronary sinus (CS) provides more anatomical insights compared with static angiographies. We evaluated intraprocedural three-dimensional (3D) CS reconstruction (RC) based on RA, using syngo(®) DynaCT Cardiac to guide CS lead implantation. METHODS AND RESULTS: In 24 patients with indication for cardiac resynchronization therapy, intraprocedural RA and 3D RC of the CS was performed. Lead placement was guided by 3D image integration into real-time fluoroscopy. Rotational angiography and 3D RCs were evaluated regarding visibility of the CS and tributaries, CS-to-target vein angles, and vessel diameters. The target vein for CS lead implantation, identified by RA, was successfully displayed by 3D RC in 20 (91%) of 22 patients with adequate RA. All lead implantations were guided successfully by 3D image integration into real-time fluoroscopy. Cranial or caudal angulations were used in 95% of the procedures without further angiographies. Rotational angiography displayed a mean of 2.9 ± 1.0 second-order side branches compared with 1.8 ± 1.1 in 3D RCs (P< 0.05). The CS-to-target vein angle estimated from static projections (right anterior oblique 20°, left anterior oblique 40°, and even optimal RA view) differed substantially from 3D RCs. Main vessel diameters did not differ significantly between both techniques. CONCLUSION: Intraprocedural 3D RC of the CS and 3D image integration-guided lead placement is feasible. Coronary sinus-to-target vein angles seemed to be misestimated even by RA views compared with 3D RC. Thus RA and 3D CS RC should be applied routinely for CS lead implantation.

Criteria for patient selection in cardiac resynchronization therapy.

Since the implementation of cardiac resynchronization therapy (CRT) the prognosis of patients with severe heart failure has been improved owing to a reduction in morbidity and mortality rates, as several multicenter trials have shown. However, several patients treated by CRT still lack improvement or even deteriorate during therapy. In some of them, this might be due to the severity and progression of chronic heart failure. In others, the criteria for the indication of CRT and/or optimized device programming might have not been met. Thus, one important option to improve CRT outcome is to improve CRT patient selection. A lot of publications describing various methods identifying a positive or negative prediction of CRT have been released. In summary, decision making based on all these partly contradictory publications indicate a strong need for guidelines for the use of such expensive therapy. The purpose of this article is to give an overview of CRT and summarize the different methods and the limitations of CRT patient selection parameters. With the focus of the different guidelines, this article tries to give an appropriate overview and aid decision making in CRT patients, including a short view of possible new indications.

Intracardiac echocardiography improves procedural efficiency during cryoballoon ablation for atrial fibrillation: a pilot study.

UNLABELLED: Intracardiac Echocardiography Guided Cryoballoon Ablation. BACKGROUND: Cryoballoon ablation is increasingly used for pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF). This new technique aims to perform PVI safer and faster. However, procedure and fluoroscopy times were similar to conventional RF approaches. We compared ICE plus fluoroscopy versus fluoroscopy alone for anatomical guidance of PVI. METHODS: Forty-three consecutive patients with paroxysmal AF were randomly assigned to ICE plus fluoroscopy (n = 22) versus fluoroscopy alone (n = 21) for guidance of cryoballoon PVI. A "single big balloon" procedure using a 28 mm cryoballoon was performed. The optimal ICE-guided position of the cryoballoon was assessed by full ostial occlusion and loss of Doppler coded reflow to the left atrium (LA). Any further freezes were ICE-guided only without use of fluoroscopy or contrast media injection. RESULTS: A total of 171 pulmonary veins could be visualized with ICE. 80% of ICE-guided freezes were performed with excellent ICE quality. Acute procedural success and AF recurrence rate at 6 months were similar in both groups (AF recurrence: ICE-guided = 27% vs Fluoroscopy = 33%; P = ns). Patients without ICE guidance had significantly longer procedure (143 ± 27 minutes vs 130 ± 19 minutes; P = 0.05) and fluoroscopy times (42 ± 13 minutes vs 26 ± 10, P = 0.01). The total amount of contrast used during the procedure was significantly lower in patients with ICE guidance (88 ± 31 mL vs 169 ± 38 mL, P < 0.001). CONCLUSION: Additional ICE guidance appears to be associated with lower fluoroscopy, contrast, and procedure times, with similar efficacy rates. Specifically, ICE allows for better identification of the PV LA junction and more precise anatomically guided cryoballoon ablations.

Image-integration of intraprocedural rotational angiography-based 3D reconstructions of left atrium and pulmonary veins into electroanatomical mapping: accuracy of a novel modality in atrial fibrillation ablation.

INTRODUCTION: Exact visualization of complex left atrial (LA) anatomy is crucial for safety and success rates when performing catheter ablation of atrial fibrillation (AF). The aim of our study was to validate the accuracy of integrating rotational angiography-based 3-dimensional (3D) reconstructions of LA and pulmonary vein (PV) anatomy into an electroanatomical mapping (EAM) system. METHODS AND RESULTS: In 38 patients (62 +/- 8 years, 25 females) undergoing catheter ablation of paroxysmal (n = 19) or persistent (n = 19) AF, intraprocedural rotational angiography of LA and PVs was performed. The subsequent 3D reconstruction and segmentation of LA and PVs was transferred to the EAM system and registered to the EAM. The distances of all EAM points to corresponding points on the LA syngo DynaCT Cardiac surface were calculated. Segmentation of LA with clear visualization of adjacent structures was possible in all patients. Also, the integrated segmentation of the LA was used to guide the encirclement of ipsilateral veins, which resulted in PV isolation in all patients. Integration into the 3D mapping system was achieved with a distance error of 2.2 +/- 0.4 mm when compared with the EAM surface. Subgroups with paroxysmal and persistent AF showed distance errors of 2.3 +/- 0.3 mm and 2.1 +/- 0.4 mm, respectively (P = n.s.). CONCLUSION: Intraprocedural registration of LA and PV anatomy by contrast enhanced rotational angiography was feasible and accurate. There were no differences between patients with paroxysmal or persistent AF. Therefore, integration of rotational angiography-based reconstructions into 3D EAM systems might be helpful to guide catheter ablation for AF.

Role of left ventricular scar and Purkinje-like potentials during mapping and ablation of ventricular fibrillation in dilated cardiomyopathy.

BACKGROUND: Purkinje-like potentials (PLPs) have been described as important contributors to initiation of ventricular fibrillation (VF) in patients with normal hearts, ischemic cardiomyopathy, and early after-myocardial infarction. METHODS: Of the 11 consecutive patients with VF storm, nonischemic cardiomyopathy (68 +/- 22 years, left ventricular ejection fraction 28 +/- 8%) who were given antiarrhythmic drugs and/or heart failure management, five had recurrent VF and underwent electrophysiology study (EPS) and catheter ablation. RESULTS: At EPS, frequent monomorphic premature ventricular contractions (PVC) and/or ventricular tachycardia did not occur. With isoproterenol, VF was induced in three patients, and sustained monomorphic PVCs were induced in one patient. Three-dimensional electroanatomical mapping using CARTO (Biosense-Webster Inc., Diamond Bar, CA) revealed posterior wall scar in four of the five patients. PLP in sinus rhythm were recorded around the scar border in these four patients, and radiofrequency ablation targeting PLP was successfully performed at these sites. The patient without PLP did not undergo ablation. During follow-up (12 +/- 5 months), only the patient without PLP had four VF recurrences requiring implantable cardioverter-defibrillator (ICD) shocks. CONCLUSION: In patients with VF and dilated cardiomyopathy, left ventricular posterior wall scar in the vicinity of the mitral annulus seems to be a common finding. Targeting PLP along the scar border zone for ablation seems to efficiently prevent VF recurrence in these patients.

Long-term effects of dynamic atrial overdrive pacing on sleep-related breathing disorders in pacemaker or cardioverter defibrillator recipients.

INTRODUCTION: Sleep-related breathing disorders occur in 20-30% of Europeans and North Americans, including 10% of sleep apnea syndrome (SAS). A preliminary study suggested that atrial overdrive pacing with a fixed heart rate might alleviate SAS. However, it is not known whether dynamic atrial overdrive pacing alleviates SAS. METHODS: Patients with indications for a dual chamber pacemaker or implantable cardioverter-defibrillator (ICD) were screened for SAS using the Pittsburgh Sleep Quality Index (PSQI) questionnaire. If PSQI was >5, cardio-respiratory polygraphy was performed before and 4 and 7 months after device implantation. Patients were randomized to algorithm ON-OFF (group A) or OFF-ON (group B) and the apnea-hypopnea index (AHI) was measured. RESULTS: Out of 105 consecutive patients, 46 (44%) had a positive PSQI. This analysis included 12 patients (mean age = 61 +/- 10 years, body mass index 28.9 +/- 6.5 kg/m(2), left ventricular ejection fraction = 38.3 +/- 13.6%; 10 men). All patients suffered from obstructive or mixed SAS. There were no significant differences in PSQI or AHI between baseline and follow-up or between the two study groups. Therefore, the study was terminated ahead of schedule. CONCLUSIONS: The prevalence of obstructive or mixed SAS was high in pacemaker or ICD recipients and reduced left ventricular ejection fraction. In these patients, long-term dynamic atrial overdrive pacing using did not improve PSQI or SAS. Therefore, patients with relevant obstructive or mixed SAS should not be offered atrial pacing therapy.

Esophageal acid levels after pulmonary vein isolation for atrial fibrillation.

BACKGROUND: Pulmonary vein antrum isolation (PVAI) is a potentially curative, nonpharmacologic treatment of atrial fibrillation (AF). Several procedural complications have been described, including esophageal wall lesions ranging from erythema and esophagitis, necrosis and ulcer, to atrio-esophageal fistula. We prospectively studied changes in esophageal acid levels before and after PVAI. METHODS: We performed 24-hour pH-metry before and 1.3 +/- 1.6 days after PVAI, in 25 patients (mean age = 62 +/- 12 years, 17 men) with symptomatic AF. A 2-mm transnasal probe was inserted into the inferior part of the esophagus and into the stomach to measure pH levels at fixed intervals. DeMeester scores, indicating acidic gastro-esophageal reflux, were calculated. RESULTS: The mean number of reflux episodes increased from 89 +/- 80 before to 107 +/- 94 after PVAI. The mean percentage of time with esophageal pH < 4 was shorter after (108 +/- 193 minutes) than before PVAI (159 +/- 245 minutes). The mean DeMeester score decreased from 49 +/- 68 before to 31 +/- 41 after PVAI (P < 0.05). We observed erythema or esophagitis in five patients, necrosis or ulcer in seven, and atrio-esophageal fistula in no patient. CONCLUSIONS: Our hypothesis of increased acid levels caused by stimulation of the right vagal nerve during isolation of the right upper pulmonary vein was not verified.

Atrial flutter ablation in inducible patients during pulmonary vein atrum isolation: a randomized comparison.

BACKGROUND: The incidence of atrial flutter (AFL) post pulmonary vein antrum isolation (PVAI) in patients with atrial fibrillation (AF) is reported to be between 8% and 20%. The need for right or left AFL ablation during the initial PVAI procedure remains controversial. We prospectively compared mapping and ablation versus no ablative treatment of inducible AFL during PVAI. METHODS AND RESULTS: In 220 patients (167 men, mean age 56+/-15 years) with symptomatic AF presenting for PVAI, burst pacing from the high right atrium and coronary sinus was performed to determine AFL inducibility. A total of 25 patients with sustained (17 patients) or reproducible (eight patients) AFL were included in this study. Patients were randomized to mapping and ablation of AFL using the CARTO 3D mapping system (Biosense Webster, Diamond Bar, CA, USA) versus no further ablation. Typical AFL was induced in 48% of the patients. During a follow-up of 12+/-4 months, recurrences were determined by serial 48-h Holter and event monitors. Recurrence rates, time to recurrence, and AFL cycle length differences between both groups were not statistically significant. CONCLUSION: These data suggest that inducibility of AFL post PVAI does not predict long-term incidence of AFL. Moreover, this study demonstrates little benefit to mapping and ablation of these arrhythmias during the PVAI procedures.

Three-dimensional left atrial and esophagus reconstruction using cardiac C-arm computed tomography with image integration into fluoroscopic views for ablation of atrial fibrillation: accuracy of a novel modality in comparison with multislice computed tomography.

BACKGROUND: Visualization of the left atrium (LA) and pulmonary veins (PVs) is crucial in PV isolation (PVI). Additional delineation of the esophagus might avoid severe side effects. Cardiac C-arm computed tomography (DynaCT Cardiac, Siemens AG, Forchheim, Germany) has been introduced as a novel intraprocedural imaging modality based on a rotational angiography. OBJECTIVES: The purpose of this study was to prove the quantitative accuracy of DynaCT Cardiac as compared with multislice CT (MSCT) in imaging of the LA and PV in patients undergoing PVI. METHODS: Thirty-four consecutive patients (22 male, age 64 +/- 12 years) with symptomatic atrial fibrillation (AF) and indication for PVI were studied. Diameters of the PV, the LA appendage (LAA), and the descending aorta were measured, and the position of the esophagus was defined using preprocedural MSCT and intraprocedural DynaCT Cardiac. RESULTS: There was a significant correlation between both measurements for diameters of the LAA (r = 0.86, P <.05), PV (r = 0.98, P <.05), and the descending aorta (r = 0.98, P <.05). The overall correlation of vessel diameters was r = 0.99. The LA volumes correlation was r = 0.86 and P <.05. A significant difference of the esophageal position was found between preprocedural MSCT and intraprocedural DynaCT Cardiac (r = 0.53, P <.05). CONCLUSIONS: DynaCT Cardiac is a novel intraprocedural rotational angiographic technique. It is highly accurate in displaying crucial structures for PVI in comparison with the results of MSCT. Therefore, DynaCT Cardiac can be used as an alternative imaging technique to improve PVI accuracy.

Rescue-stenting of an occluded lateral coronary sinus branch for recanalization after dissection during cardiac resynchronization device implantation.

Cardiac resynchronization therapy (CRT) using left- (LV) or biventricular pacing is widely applied in selected heart failure patients. However, transvenous LV-lead placement into coronary sinus (CS) branches can be challenging. A 77-year-old female patient with New York Heart Association class III symptoms due to dilated cardiomyopathy [LV ejection fraction (LVEF): 10%, QRS-duration: 150 ms], despite optimal medical treatment presented for CRT. Coronary sinus angiograms were performed after transvenous CS cannulation. Within a large posterolateral vein, low phrenic nerve stimulation thresholds were found. The only alternative smaller tortuous lateral branch showed a significant narrowing, making LV-lead advancement impossible. Angioplasty was performed, using a venoplasty balloon. This caused complete branch occlusion. After recanalization of the vessel by implantation of a bare metal stent, the lead could be advanced through the stent. Optimal pacing parameters without phrenic nerve stimulation were established. Angioplasty of CS branches during CRT implantation procedures bears the risk of complete branch occlusion, but recanalization can acutely be achieved by stent implantation. This is the first report on rescue-stenting of a CS branch after angioplasty-related occlusion. Transthoracic lead implantation, accompanied risks, and slower recovery could thus be avoided.

Incidence of oesophageal wall injury post-pulmonary vein antrum isolation for treatment of patients with atrial fibrillation.

AIMS: Oesophageal injury has been reported with delivery of radio-frequency lesions at the left atrium posterior wall in catheter ablation procedures for atrial fibrillation (AF). In this observational study we prospectively assessed endoscopical oesophageal wall changes after pulmonary vein antrum isolation (PVAI) in patients presenting for treatment of AF. METHODS AND RESULTS: Twenty eight patients (18 men; mean age 55 +/- 11 years) were ablated using either a cooled-tip or an 8 mm tip ablation catheter. Endoscopy of the oesophagus was performed 24 h after PVAI. If oesophageal wall changes were detected post ablation, a proton-pump inhibitor (PPI) was started and repeat endoscopy was considered. Within 24 h post ablation oesophageal wall changes were confirmed in 47% of our study patients. Erythema was identified in 29% and necrotic or ulcer-like changes in 18% of patients. None of study patients experienced left atrial-oesophageal fistula. A significant correlation between Reflux-like symptoms and oesophageal wall changes was demonstrated. Complete recovery of oesophageal lesions was shown in all study patients 2-4 weeks post ablation. CONCLUSION: A significant number of patients experienced oesophageal wall injury post PVAI. Initiating PPIs in this group of patients might facilitate recovery of oesophageal wall injuries caused by radio-frequency energy delivery.

Randomized comparison between open irrigation technology and intracardiac-echo-guided energy delivery for pulmonary vein antrum isolation: procedural parameters, outcomes, and the effect on esophageal injury.

INTRODUCTION: We performed a prospective study to compare efficacy and safety of both open irrigation tip (OIT) technology with intracardiac echo (ICE)-guided energy delivery in patients presenting for PVAI. METHODS AND RESULTS: Fifty-three patients presenting for PVAI were randomized to ablation using an OIT catheter (Group 1, 26 patients; temperature and power were set at 50 degrees and 50 W, respectively, with a saline pump flow rate of 30 mL/min) or radiofrequency (RF) energy delivery under ICE guidance (Group 2, 27 patients; energy was titrated based on microbubbles formation). The mean procedure time and fluoroscopy exposure were lower in Group 1 (164 +/- 42 min and 7,560 +/- 2,298 microGray m2 vs 204 +/- 47 min and 12,240 +/- 4,356 microGray m2; P = 0.005 and 0.008, respectively). Moreover, the durations of RF lesions applied per PV antrum was lower in Group 1 compared with Group 2 (5.1 +/- 2.2 min vs 9.2 +/- 3.2 min, P = 0.03, respectively). Within 24 hours after PVAI in 35.7% (all erythema) of Group 1 and 57.1% (21.4% erythema and 35.7% necrosis) of Group 2, patients' esophageal wall changes were documented. After 14 +/- 2 months of follow up, recurrences were documented in 19.2% of Group 1 and 22.2% of Group 2 patients. CONCLUSION: Although both OIT and ICE-guided energy delivery possess a similar effect in treating AF, OIT seems to be superior in terms of achieving isolation and shortening fluoroscopy exposure. Moreover, a lower incidence of esophageal wall injury was observed utilizing OIT for PVAI.