Impact of contact force sensing technology on outcome of catheter ablation of idiopathic pre-mature ventricular contractions originating from the outflow tracts.

AIMS: Catheter ablation of frequent idiopathic pre-mature ventricular contractions (PVC) is increasingly performed. While potential benefits of contact force (CF)-sensing technology for atrial fibrillation ablation have been assessed in several studies, the impact of CF-sensing on ventricular arrhythmia ablation remains unknown. This study aimed to compare outcomes of idiopathic outflow tract PVC ablation when using standard ablation catheters as opposed to CF-sensing catheters. METHODS AND RESULTS: In a retrospective multi-centre study, unselected patients undergoing catheter ablation of idiopathic outflow tract PVCs between 2013 and 2016 were enrolled. All procedures were performed using irrigated-tip ablation catheters and a 3D electro-anatomical mapping system. Sustained ablation success was defined as a ≥80% reduction of pre-procedural PVC burden determined by 24 h Holter ECG during follow-up. Overall, 218 patients were enrolled (median age 52 years, 51% males). Baseline and procedural data were similar in the standard ablation (24%) and the CF-sensing group (76%). Overall, the median PVC burden decreased from 21% (IQR 10-30%) before ablation to 0.2% (IQR 0-3.0%) after a median follow-up of 2.3 months (IQR 1.4-3.9 months). The rates of both acute (91% vs. 91%, P = 0.94) and sustained success (79% vs. 74%, P = 0.44) were similar in the standard ablation and the CF-sensing groups. No differences were observed in subgroups according to arrhythmia origin from the RVOT (65%) or LVOT (35%). Complications were rare (1.8%) and evenly distributed between the two groups. CONCLUSION: The use of CF-sensing technology is not associated with increased success rate nor decreased complication rate in idiopathic outflow tract PVC ablation.

The Medtronic Sprint Fidelis® lead history revisited-Extended follow-up of passive leads.

BACKGROUND: Due to high failure rates, Medtronic withdrew the Sprint Fidelis lead (SFL) from the market. Passive fixation lead models exhibited better survival than active models, but most studies have limited follow-up. Aim of this study was to give insights into passive lead survival with a follow-up of 10 years. METHODS: In two large Swiss centers, patients with passive SFLs were identified and data from routine implantable cardioverter defibrillator (ICD) follow-ups were collected. Patients were censored at time of death, last device interrogation (if lost to follow-up), time of lead revision (in non-SFL-related problems), or at database closure (31th December 2017). We defined lead failure as any of the following: lead fracture with inappropriate discharge; sudden increase in low-voltage impedance to >1500 or high-voltage impedance to >100 Ω; >300 nonphysiological short VV-intervals. RESULTS: We identified 145 patients. Age at implant was 60 ± 12 years with a median follow-up of 10.2 (interquartile range [IQR]: 5.0-11.2) years. Thirty-five percent of patients died after 5.4 ± 2.7 years. A total of 19 leads (13%) failed after 6.7 ± 3.2 years (range: 1.2-12.0). Overt malfunction with shocks existed in four patients (3%). Cumulative lead survival was 93.1% at 6, 88.2% at 8, 83.8% at 10, and 77.6% at 11 years, respectively, with 35% of implanted leads under monitoring at 10 years. Lead survival fits best a Weibull distribution with accelerating failure rates (k = 1.95, 95% CI 1.32-2.87, P < 0.001). CONCLUSIONS: During very long-term follow-up, failure rate of the passive SFL shows an increase resulting in an impaired lead survival of 84% at 10 years.

Individually tailored vs. standardized substrate modification during radiofrequency catheter ablation for atrial fibrillation: a randomized study.

Aims: This randomized single-centre study sought to compare the efficacy and safety of pulmonary vein isolation (PVI) plus voltage-guided ablation vs. PVI with or without linear ablation depending on the type of atrial fibrillation (AF). Methods and results: Overall, 124 ablation-naive patients with paroxysmal or persistent AF were randomized to PVI with (persistent AF) or without (paroxysmal AF) additional linear ablation (control group) vs. PVI plus ablation of low-voltage areas (LVAs) irrespective of AF type. Bipolar voltage mapping was performed during stable sinus rhythm. An LVA consisted of ≥ 3 adjacent mapping points that each had a peak-to-peak amplitude ≤0.5 mV. After a mean follow-up of 12 ± 3 months, significantly more patients in the LVA ablation group were free from atrial arrhythmia recurrence >30 s off antiarrhythmic drugs (AADs) after a single procedure (primary endpoint) compared with control group patients [40/59 (68%) vs. 25/59 (42%), log-rank P = 0.003]. Arrhythmia-free survival on or off AADs was found in 33/59 control group patients (56%) and in 41/59 LVA ablation group patients (70%) (adjusted log-rank P = 0.10). During the 7 day Holter monitoring period at 12 months, significantly more patients in the LVA ablation group were free from arrhythmia recurrence on or off AADs [45/50 (90%) vs. 33/46 (72%), P = 0.04]. No between-group differences were observed regarding procedure duration, fluoroscopy time, and major complications. Conclusion: In this single-centre study, individually tailored substrate modification guided by voltage mapping was associated with a significantly higher arrhythmia-free survival rate compared with a conventional approach applying linear ablation according to AF type.

[Rational use of ambulatory ECG recordings]. / Diagnose von Herzrhythmusstörungen - sinnvoller Einsatz von Holter, Event Rekordern, Loop Rekordern sowie Schrittmacher- und ICD-Speichern.

Ambulatory ECG recordings and the memory function of cardiac devices are very useful to record arrhythmias. For this purpose various modalities of documentation are available including externally worn ECGs with variable recording duration and implantable cardiac devices with recording periods over years. The probably most frequent indication for an ambulatory ECG recording is syncope. In contrast to episodic palpitations, syncope is associated with hemodynamic impairment and reduced cerebral perfusion which precludes visiting a physician in order to record an ECG during the attack. Furthermore, ambulatory ECG might be useful in patients with short-lasting palpitations. A selective application of this diagnostic tool might also be appropriate in asymptomatic patients, particularly in order to search for episodes of atrial fibrillation. This indication is of great interest since the introduction of pulmonary vein isolation as a valuable therapeutic option in atrial fibrillation patients to document asymptomatic recurrences for quality control reasons.

Anatomical predictors for acute and mid-term success of cryoballoon ablation of atrial fibrillation using the 28 mm balloon.

INTRODUCTION: Cryoballoon (CB) pulmonary vein isolation (CB-PVI) for the treatment of paroxysmal atrial fibrillation (AF) has been demonstrated to be safe and reliable. Preprocedural patient selection to address the high variability in pulmonary vein (PV) anatomy may improve the acute and chronic success of CB-PVI. The purpose of this study was to identify anatomical predictors for CB-PVI failure using the 28 mm balloon. METHODS AND RESULTS: We included 47 patients with paroxysmal AF undergoing CB-PVI with the 28 mm CB. Anatomical global left atrial and PV selective parameters were quantified from 3-dimensional reconstructed preprocedural computed tomography or magnetic resonance imaging data. The mean follow-up was 26 ± 9 months (range: 12-32 months). Multivariate logistic regression analysis revealed that a continuous sharp left lateral ridge between the left PVs and the left lateral appendage (OR, 7.09; 95% CI, 1.17-43.47) and a sharp carina between the left superior and left inferior PV (OR, 5.99; 95% CI, 1.33-27.03) predict acute and mid-term failure. For the right inferior PVs, a non-perpendicular angle between the axis of the PV and the ostial plane (OR, 6.33; 95% CI, 1.20-33.33) and an early branching PV with change in the axis angle (OR, 7.41; 95% CI, 1.44-38.46) were predictors of acute and mid-term failure. CONCLUSION: Anatomical variables preventing maximal heat transfer from the tissue to the CB could be identified as predictors for CB-PVI failure with the 28 mm balloon. These findings may be a step toward a more tailored ablation strategy based on individual anatomical variations.

Long-term efficacy of single procedure remote magnetic catheter navigation for ablation of ischemic ventricular tachycardia: a retrospective study.

BACKGROUND: Remote magnetic navigation (RMN) aims to reduce some inherent limitations of manual radiofrequency (RF) ablation. However, data comparing the effectiveness of both methods are scarce. This study evaluated the acute and long-term success of RMN guided versus manual RF ablation in patients with ischemic sustained ventricular tachycardia (sVT). METHODS: One hundred two consecutive patients (age 68 ± 10 years, LVEF 32 ± 12%, 88 men) with ischemic sVT were ablated with RMN (Stereotaxis; 49%) or manually (51%) using substrate and/or activation mapping (Carto) and open-irrigated-tip catheters. All received implantable defibrillators or loop recorders. Acute success was defined as noninducibility of any sVT at the end of the ablation procedure and long-term success as freedom from VT upon follow-up. RESULTS: There was no difference in the baseline characteristics between the groups. Three patients died in hospital. Acute success rate was similar for RMN and manual ablation (82% vs 71%, P = 0.246). RMN was associated with significantly shorter fluoroscopy time (13 ± 12 minutes vs 32 ± 17 minutes, P = 0.0001) and RF time (2337.59 ± 1248.22 seconds vs 1589.95 ± 1047.42 seconds, P = 0.049), although total procedure time was similar (157 ± 40 minutes vs 148 ± 50 minutes, P = 0.42). There was a nonsignificant trend toward better long-term success in RMN group: after a median of 13 (range 1-34) months, 63% in the RMN and 53% in the manual ablation group were free from VT recurrence (P = 0.206). CONCLUSION: RMN guided RF ablation of ischemic sustained VT is equally efficient compared with manual ablation in terms of acute and long-term success rate. These results are achieved with a significantly reduced fluoroscopy time and shorter RF time.

The prognosis of implantable defibrillator patients treated with cardiac resynchronization therapy: comorbidity burden as predictor of mortality.

AIMS: Comorbidity, such as myocardial infarction, diabetes, and renal failure, plays a pivotal role in the prognosis of a patient with arrhythmias. However, data on the prognostic impact of comorbiditiy in heart failure patients with cardiac resynchronization therapy and defibrillation (CRT-D) are scarce. The purpose of this study was to determine the impact of comorbidity on survival in CRT-D patients. METHODS AND RESULTS: The study population consisted of 463 heart failure patients who received a CRT-D between 1999 and 2008 in Rotterdam and Basel. The Charlson comorbidity index (CCI) is often used as an adjusting variable in prognostic models. The Cox proportional hazards analysis was performed to determine the independent effect of comorbidity on survival. During a median follow-up of 30.5 months, 85 patients died. Mortality rates at 1 and 7 years were 6.3 and 32.3%. Cumulative incidence of implantable cardioverter defibrillator (ICD) therapy at 7 years was 50%, and death without ICD therapy was observed in 9% of patients. At least three comorbid conditions were observed in 81% of patients. Patients who died had a higher CCI score compared with those who survived (3.9 ± 1.5 vs. 2.9 ± 1.5; P < 0.001). An age-adjusted CCI score ≥ 5 was a predictor of mortality (hazard ratio 3.69, 95% CI 2.06-6.60; P < 0.001) independent from indication for ICD therapy, and from ICD interventions during the clinical course. CONCLUSION: Comorbidity is often present in heart failure patients, and a high comorbidity burden was a significant predictor of mortality in CRT-D recipients. Comorbidity cannot predict appropriate ICD therapy. Death without prior ICD therapy occurs in a minor proportion of patients.

Remote monitoring of cardiovascular implantable electronic devices: prerequisite or luxury?

The number of patients implanted with cardiovascular electronic devices (CIED) like implantable defibrillators (ICD), cardiac resynchronisation (CRT) devices, and pacemakers continues to grow. These devices require regular follow-up interrogation in dedicated device clinics. Contemporary CIED are capable of wireless remote interrogation and monitoring. This technology has been proven to be technically reliable and helpful in certain conditions. It is of particular benefit in monitoring devices that are under a safety alert since it allows early identification of device malfunction and minimises the risk of under-reporting. There is also strong evidence that it helps to reduce heart failure hospitalisations in CRT and ICD patients. Furthermore, this technology proves to be very helpful in the early detection of arrhythmias like atrial fibrillation or ventricular tachyarrhythmias. Remote monitoring significantly reduces the number of follow-up visits, patients' and physicians' time spent per visit, and increases patients' adherence to follow-up visits. Future studies are needed to determine how to best allocate this new technology in a cost-effective manner.

[Drug induced QT prolongation]. / Medikamentös induzierte Verlängerung des QT-Intervalls.

Prolongation of the ventricular repolarisation manifests itself as a prolongation of the QT intervall on the surface ECG and represents a major risk for a special form of ventricular tachycardia called "torsades de pointes". Torsades de pointes are often self limited and are associated with palpitations, dizziness or syncope. Degeneration into ventricular fibrillation and sudden cardiac death can occur. In addition to the various forms of the congenital long QT syndrome many drugs, such as antiarrhythmic drugs class IA and III, antibiotics, antihistamines, antidepressants, and methadone are known to prolong the QT interval. Most of these drugs block a specific potassium channel substantially involved in the ventricular repolarisation. In addition, drug interaction or disturbances of drug metabolism may play a major role in the acquired form of the long QT syndrome. The individual risk and the potential of a pharmacologic substance to prolong the QT interval are not predictable. Certain risk factors identify patients at higher risk for drug-induced prolongation of the QT interval. Correctable factors include electrolyte disorders (e.g. hypokalemia) and concomitant administration of different QT prolonging drugs. External defibrillation is the therapy of choice in the hemodynamic unstable patient presenting torsades de pointes. In hemodynamic more stable patients application of intravenous magnesium can terminate torsades de pointes (membrane stabilizing properties). Temporary external or transvenous pacing at high heart rate might terminate incessant torsades de pointes by decreasing QT interval. Repeated ECG controls during therapy with QT prolonging drugs are mandatory, especially when drug doses are changed, additional drugs are prescribed, or in case of vomiting and diarrhea. QT prolongation in individual medical therapy is not always predictable. Therefore, updated lists of drugs with the potential of QT prolongation are available on the Internet (e.g. www.qtdrugs.org ).

First clinical experience of a dedicated irrigated-tip radiofrequency ablation catheter for the ablation of cavotricuspid isthmus-dependent atrial flutter.

BACKGROUND: Different types of irrigated-tip ablation catheters are available for ablation of atrial flutter (AFL). The aim of this study was to compare an established with a novel dedicated Gold irrigated-tip catheter for ablation of AFL. METHODS AND RESULTS: We compared consecutive patients undergoing ablation of AFL using a standard 3.5 mm irrigated-tip platinum-iridium (Pt-Ir) catheter (Thermocool, TC-group) and a 3.5 mm irrigated gold-tip catheter (Gold-group) specifically designed for cavotricuspid isthmus ablation (CTI). The primary endpoint was acute efficacy (net RF time) to achieve block across the CTI. Secondary endpoints included procedure time, fluoroscopy duration, complications, and recurrence of AFL.153 patients (age 68 ± 11 years, 74% male) were included. Net RF time to achieve CTI block was not different between the TC-group (793 ± 503 s) and the Gold-group (706 ± 422 s; p = 0.406). Total procedure time was not significantly different between the TC-group (70 ± 26 min) and the Gold-group (70 ± 27 min; p = 0.769). A significant difference between the groups was identified for the fluoroscopy duration (TC-group: 934 ± 537 s, Gold-group: 596 ± 362 s, p < 0.001). There were no major complications observed in the groups. Recurrence of AFL occurred in 3 of 66 (5%) in the TC-group and in 2 of 87 (2%) in the Gold-group (p = 0.652). CONCLUSIONS: In conclusion, acute and chronic efficacy of the irrigated Pt-Ir and gold-tip catheters were comparable. However, the dedicated catheter design was associated with decreased fluoroscopy duration.

Tailored atrial substrate modification based on low-voltage areas in catheter ablation of atrial fibrillation.

BACKGROUND: Reduced electrogram amplitude has been shown to correlate with diseased myocardium. We describe a novel individualized approach for catheter ablation of atrial fibrillation (AF) based on low-voltage areas (LVAs) in the left atrium (LA). We sought to assess (1) the incidence of LVAs in patients undergoing AF catheter ablation, (2) the distribution of LVAs within the LA, and (3) the effect of an individualized ablation strategy on long-term rhythm outcomes. METHODS AND RESULTS: In 178 patients with paroxysmal or persistent AF, LA voltage maps were created during sinus rhythm after circumferential pulmonary vein isolation. Subsequent substrate modification was confined to the presence of LVA (<0.5 mV) and inducible regular atrial tachycardias. LVAs were identified in 35% and 10% of patients with persistent and paroxysmal AF, respectively. The LA roof and the anterior, septal, and posterior wall LA were most often affected. The 12-month atrial tachycardias/AF-free survival was 62% for patients without LVAs and 70% for patients with LVAs and tailored substrate modification (P=0.3). Success rate in a comparison group of 26 LVA patients without further substrate modification was 27%. CONCLUSIONS: LVAs can be found at preferred sites in 10% of patients with paroxysmal AF and in 35% of patients with persistent AF. This is the first clinical report describing a consistent voltage-based approach for substrate modification in addition to circumferential pulmonary vein isolation irrespective of AF type. Application of this limited individualized approach may have the potential to compensate for the impaired 12-month outcome of patients with endocardial structural defects.

Long-term comparison of cryoballoon and radiofrequency ablation of paroxysmal atrial fibrillation: a propensity score matched analysis.

BACKGROUND: Although radiofrequency (RF) and cryoballoon (CB) based technologies for pulmonary vein isolation (PVI) have both individually been demonstrated to be effective and safe for the treatment of paroxysmal AF, head-to-head comparisons are lacking. The purpose of this study was to compare the outcome of cryoballoon versus radiofrequency ablation in patients with paroxysmal atrial fibrillation undergoing pulmonary vein isolation. METHODS: Out of a prospective registry of 327 patients undergoing PVI, 208 patients (age 58±11 years, ejection fraction 59±6%, left atrial size 39±6 mm) with paroxysmal AF were identified. The presented dataset was obtained by 1:1 propensity score matching and contained 142 patients undergoing CB-PVI or RF-PVI in conjunction with a 3D mapping system, respectively. We compared single procedure efficacy of the two methods using a Cox proportional hazards model. RESULTS: After a mean follow-up of 28 months and a single procedure, AF recurred in 37 of 71 (52%) in the CB-PVI group and in 31 of 71 patients (44%) in the RF-PVI group (HR [95% CI]=1.19 [0.74, 1.92], p=0.48). Recurrence of AF for PVI using solely the CB was observed in 23 of 51 (45%) patients and in 23 of 51 (45%) patients in the corresponding RF-PVI group (HR [95% CI]=0.93 [0.52, 1.66], p=0.81). Complication rate was not different between the groups. CONCLUSION: A propensity score matched comparison between CB-PVI and RF-PVI using a 3D-mapping system for AF ablation showed similar long-term success rates.

Validation of a novel spiral mapping catheter for real-time recordings from the pulmonary veins during cryoballoon ablation of atrial fibrillation.

BACKGROUND: The Achieve mapping catheter allows real-time recordings from the pulmonary veins (PVs) during cryoballoon (CB) ablation of atrial fibrillation (AF). OBJECTIVE: To assess the clinical applicability of the Achieve mapping catheter and the value of real-time recordings from the PVs during CB. METHODS: Patients with paroxysmal AF undergoing CB ablation were studied. Recordings from the PVs were analyzed during (real-time recordings) and after CB ablation and validated by using a variable circumferential mapping catheter (Achieve group; n = 20). A comparison was made by using a group of patients in whom CB ablation with a guidewire and a variable circumferential mapping catheter was performed (Guidewire group; n = 20). RESULTS: Forty patients (age 58±11 years; ejection fraction 0.59±0.07; left atrial size 40±6 mm) with paroxysmal AF were included. In the Achieve group, real-time recordings from the PVs could be obtained in 40 of 80 (50%) PVs and could be seen more often at the left-sided PVs (25 of 39, 64%) than at the right-sided PVs (15 of 41, 37%; P = .02). Validation with a standard circumferential mapping catheter confirmed PV isolation in 75 of 80 (93%) PVs. After a single procedure and a follow-up of 14±4 months, 25 of 40 (63%) patients were in sinus rhythm with no significant difference between groups. CONCLUSIONS: The Achieve catheter can be used as a substitute for a guidewire during CB ablation, but real-time recordings can be obtained only in half of the PVs and are not sufficient to accurately confirm isolation of all PVs.

Phrenic nerve palsy during ablation of atrial fibrillation using a 28-mm cryoballoon catheter: predictors and prevention.

PURPOSE: The purposes of this study were to determine whether predictors of phrenic nerve palsy (PNP) exist and to test whether a standardized ablation protocol may prevent PNP during cryoballoon (CB) ablation using the 28 mm CB. METHODS: Three-dimensional (3D) geometry of the pulmonary veins (PV) and their relationship to the superior vena cava (SVC) was analyzed. Phrenic nerve (PN) stimulation was performed during ablation of the right-sided PVs with a 28-mm CB. The freezing cycle was immediately terminated in case of loss of PN capture. RESULTS: Sixty-five patients (age, 58 ± 11 years; ejection fraction, 0.59 ± 0.06; left atrial size, 40 ± 5 mm) with paroxysmal atrial fibrillation were included. No persistent PNP was observed. Transient PNP occurred in 4 of 65 patients (6 %). PN function normalized within 24 h in all four patients. A short distance between the right superior PV and the SVC was significantly associated with PNP, but left atrial and 3D PV anatomy were not. Low temperature early during the freezing cycle (<-41 °C at 30 s) predicted PNP with a sensitivity and a specificity of 100 and 98 %, respectively. CONCLUSION: The anatomical relationship between the right superior PV and the SVC is a preprocedural predictor for the development of transient PNP, and low temperature early during ablation at the right superior PV is a sensitive warning sign of impending PNP. Despite the use of the 28 mm CB, transient PNP occurred in 6 % of patients undergoing CB ablation.

Prevalence of severely impaired left ventricular ejection fraction after reperfused ST-elevation myocardial infarction.

BACKGROUND: Preventive implantation of an implantable cardioverter defibrillator (ICD) early after myocardial infarction failed to demonstrate a survival benefit in patients with depressed left ventricular ejection fraction (LVEF). This may be explained by early recovery of the LVEF after percutaneous coronary intervention (PCI). We sought to determine the incidence of a sustained LVEF ≤35% in patients with severely depressed LVEF early after a revascularised acute ST-segment elevation myocardial infarction (STEMI). METHODS: LVEF was assessed in patients with an acute STEMI treated with PCI in two Swiss high-volume centres within 10 days (in-hospital LVEF) after the STEMI. Those with an in-hospital LVEF ≤35% were scheduled for follow-up LVEF measurement within 6-8 weeks. RESULTS: A total of 330 patients were included (79% male, mean age 63 ± 12 years). In-hospital LVEF measured 3 ± 3 days after STEMI was ≤35% in 32/330 patients (10%, 95% confidence interval (CI) 13%-67%). LVEF was available in 31/32 (97%) patients at follow-up 53 ± 19 days after STEMI and improved to >35% in 19 patients (61%, 95% CI 42%-78%). The incidence of a LVEF ≤35% at follow-up was 39% (12/31, 95% CI 22%-56%). CONCLUSION: Our data demonstrate that the incidence of severely impaired LV function 53 ± 19 days after a STEMI treated with PCI is low. A severely depressed LVEF early after STEMI was present in 10% of all patients. Only 39% of these patients had a persistently impaired LVEF during follow-up. These findings support an expectant strategy before considering primary preventive ICD implantation after STEMI.

Sustained monomorphic left ventricular outflow tract tachycardia early after aortic valve replacement.

Sustained monomorphic ventricular tachycardia (VT) after valve surgery is uncommon. Cases of focal VT or bundle-branch re-entry after aortic valve surgery have been reported. We present the case of a 60 year-old patient with an incessant outflow tract VT early after aortic valve replacement. We suggest the disease process affecting the valve and adjacent area, and/or the surgical procedure, might somehow relate to VT substrate adjacent to the aortic annulus.

Clinical impact of screening for sleep related breathing disorders in atrial fibrillation.

OBJECTIVE: The aim of this study was to quantify daytime symptoms in atrial fibrillation (AF) patients with and without sleep related breathing disorders (SRBD). BACKGROUND: SRBD are common in patients with AF but little is known about daytime symptoms among those with SRBD. METHODS: Patients with AF admitted to clinics of two tertiary referral hospitals for a variety of different cardiovascular diseases were screened with a trans-nasal airflow measurement device allowing measurement of the apnea-hypopnea-index. Data on cardiac risk factors, left ventricular ejection fraction (LVEF) and cardiac medication were collected. Presence of SRBD was defined as an AHI ≥ 15/h. The Epworth sleepiness scale (ESS) was used to quantify daytime symptoms. RESULTS: Of 102 screened patients 8 were excluded due to device malfunction (n=1), dislocation of nasal cannula (n=6), or hyperthyroidism (n=1). Among the remaining 94 patients, 40 (43%) were diagnosed with SRBD. Patients with and without SRBD had similar age, body mass index, LVEF and cardiac medication. The prevalence of coronary artery disease was higher in patients with SRBD than in those without (50 vs. 17%; p=0.0007). ESS score was low and similar in both groups (no SRBD: median 4, interquartile range (IQR) 2-4 vs. SRBD: 5, IQR 3-8; p=0.14). Only 6/40 (5%) of the patients underwent overnight polysomnography and 2 (5%) started CPAP ventilation during follow-up. CONCLUSIONS: Even though SRBD are common in patients with AF, the prevalence of daytime symptoms is rare. Consequently, most patients will not initiate CPAP ventilation after positive SRBD screening.

Treating Atrial Fibrillation With Cryoballoon Technology.

Cryoballoon ablation has emerged as a novel tool to perform pulmonary vein isolation. The aim of this paper is to review the advantages, drawbacks as well as possible complications and clinical outcomes of this technology and to discuss some important technical issues.