High incidence of (ultra)low oesophageal temperatures during cryoballoon pulmonary vein isolation for atrial fibrillation.

BACKGROUND: Low oesophageal temperatures (OTs) during cryoballoon pulmonary vein isolation (PVI) have been associated with complications. This study assessed the incidence of low OT in clinical practice during cryoballoon PVI and verified possible predictive values for low OT. METHODS: Consecutive patients who underwent PVI using the second-generation cryoballoon were retrospectively included. The distance from the oesophagus to the different pulmonary veins (PVs) (OP distance), body mass index (BMI), sex, age, balloon temperature and application time were studied as potential predictors of low OTs. Computed tomography was performed before the procedure to determine the OP distance. OT was measured using an oesophageal temperature probe. Applications were ended prematurely if the OT reached <16 °C. Low and ultralow OT were defined as OT <20 and <16 °C respectively. RESULTS: Two hundred and four patients were included. Low OT was observed in 54 patients (26%) and 27 patients (13%) reached ultralow OTs. OP distance was the only predictor of low OTs after multivariate analysis. A cut-off value of 19 mm showed 96.2% sensitivity and 37.8% specificity in predicting low OTs. No clinically relevant relation was found between low OTs and BMI, age, sex, balloon temperature or application duration. CONCLUSIONS: The incidence of low OT was 26% for cryoballoon PVI. OP distance was the only predictor of low OTs. Since an OP distance <19 mm was present in all patients in at least one PV, we recommend routine OT measurement during PVI cryoballoon therapy to prevent oesophagus-related complications.

Use of three-dimensional computed tomography overlay for real-time cryoballoon ablation in atrial fibrillation reduces radiation dose and contrast dye.

AIMS: Cryoballoon pulmonary vein (PV) isolation in patients with atrial fibrillation has proven to be effective in short-term and long-term follow-up. To visualise the PV anatomy, pre-ablation contrast pulmonary venography is commonly performed. Three-dimensional (3D) computed tomography (CT) overlay is a new technique creating a live 3D image of the left atrium by integrating a previously obtained CT scan during fluoroscopy. To evaluate the benefits of 3D CT overlay during cryoballoon ablation, we studied the use of 3D CT overlay versus contrast pulmonary venography in a randomised fashion in patients with paroxysmal atrial fibrillation undergoing cryoballoon PV isolation. METHODS AND RESULTS: Between October 2012 and June 2013, 30 patients accepted for PV isolation were randomised to cryoballoon PV isolation using either 3D CT overlay or contrast pulmonary venography. All patients underwent a pre-procedural cardiac CT for evaluation of the anatomy of the left atrium (LA) and the PVs. In the 3D CT overlay group, a 3D reconstruction of the LA and PVs was made. An overlay of the CT reconstruction was then projected over live fluoroscopy. Patients in the contrast pulmonary venography group received significantly more contrast agent (77.1 ± 21.2 cc vs 40.1 ± 17.6 cc, p < 0.001) and radiation (43.0 ± 21.9 Gy.cm2 vs 28.41 ± 11.7 Gy.cm2, p = 0.04) than subjects in the 3D CT overlay group. There was no difference in total procedure time, fluoroscopy time and the amount of cryoapplications between the two groups. CONCLUSION: The use of 3D CT overlay decreases radiation and contrast dye exposure and can assist in guiding cryoballoon-based PV isolation.

Prognostic value of microvolt T-wave alternans in a real-world ICD population. Twente ICD Cohort Studie (TICS).

INTRODUCTION: Survival benefit from ICD implantation is relatively low in primary prevention patients. Better patient selection is important to maintain maximum survival benefit while reducing the number of unnecessary implants. Microvolt T-wave alternans (MTWA) is a promising risk marker. In this study, we aimed to evaluate the predictive value of MTWA in ICD patients. METHODS AND RESULTS: This study was a substudy of the Twente ICD Cohort Study (TICS). Patients with ischaemic or non-ischaemic left ventricular dysfunction who received an ICD following current ESC guidelines were eligible for inclusion. Exercise-MTWA was performed and classified as non-negative or negative. The primary endpoint was the composite of mortality and appropriate shock therapy. Analysis was performed in 134 patients (81 % male, mean age 62 years, mean ejection fraction 26.5 %). MTWA was non-negative in 64 %. There was no relation between non-negative MTWA testing and mortality and/or appropriate shock therapy (all p-values >0.15). Due to clinical conditions, 24 % were ineligible for testing. These patients experienced the highest risk for mortality (p < 0.01). CONCLUSION: Non-negative MTWA testing did not predict mortality and/or appropriate shock therapy. Furthermore, MTWA testing is not feasible in a large percentage of patients. These ineligible patients experience the highest risk for mortality.

Optimisation of cardiac resynchronization therapy in clinical practice during exercise.

AIMS: Although cardiac resynchronisation therapy (CRT) is an established treatment to improve cardiac function, a significant amount of patients do not experience noticeable improvement in their cardiac function. Optimal timing of the delay between atrial and ventricular pacing pulses (AV delay) is of major importance for effective CRT treatment and this optimum may differ between resting and exercise conditions. In this study the feasibility of haemodynamic measurements by the non-invasive finger plethysmographic method (Nexfin) was used to optimise the AV delay during exercise. METHODS AND RESULTS: Thirty-one patients implanted with a CRT device in the last 4 years participated in the study. During rest and in exercise, stroke volume (SV) was measured using the Nexfin device for several AV delays. The optimal AV delay at rest and in exercise was determined using the least squares estimates (LSE) method. Optimisation created a clinically significant improvement in SV of 10 %. The relation between HR and the optimal AV delay was patient dependent. CONCLUSION: A potential increase in SV of 10 % can be achieved using Nexfin for optimisation of AV delay during exercise. A considerable number of patients showed benefit with lengthening of the AV delay during exercise.

Incidence and predictors of phantom shocks in implantable cardioverter defibrillator recipients.

BACKGROUND: Implantable cardioverter defibrillators (ICDs) are designed to deliver shocks or antitachycardia pacing (ATP) in the event of ventricular arrhythmias. During follow-up, some ICD recipients experience the sensation of ICD discharge in the absence of an actual discharge (phantom shock). The aim of this study was to evaluate the incidence and predictors of phantom shocks in ICD recipients. METHODS: Medical records of 629 consecutive patients with ischaemic or dilated cardiomyopathy and prior ICD implantation were studied. RESULTS: With a median follow-up of 35 months, phantom shocks were reported by 5.1 % of ICD recipients (5.7 % in the primary prevention group and 3.7 % for the secondary prevention group; p=NS). In the combined group of primary and secondary prevention, there were no significant predictors of the occurrence of phantom shocks. However, in the primary prevention group, phantom shocks were related to a history of atrial fibrillation (p=0.03) and NYHA class

Infarct tissue characteristics of patients with versus without early revascularization for acute myocardial infarction: a contrast-enhancement cardiovascular magnetic resonance imaging study.

Histopathological studies have suggested that early revascularization for acute myocardial infarction (MI) limits the size, transmural extent, and homogeneity of myocardial necrosis. However, the long-term effect of early revascularization on infarct tissue characteristics is largely unknown. Cardiovascular magnetic resonance (CMR) imaging with contrast enhancement (CE) allows non-invasive examination of infarct tissue characteristics and left ventricular (LV) dimensions and function in one examination. A total of 69 patients, referred for cardiac evaluation for various clinical reasons, were examined with CE-CMR >1 month (median 6, range 1-213) post-acute MI. We compared patients with (n = 33) versus without (n = 36) successful early revascularization for acute MI. Cine-CMR measurements included the LV end-diastolic and end-systolic volumes (ESV), LV ejection fraction (LVEF, %), and wall motion score index (WMSI). CE images were analyzed for core, peri, and total infarct size (%), and for the number of transmural segments. In our population, patients with successful early revascularization had better LVEFs (46 ± 16 vs. 34 ± 14%; P < 0.01), superior WMSIs (0.53, range 0.00-2.29 vs. 1.42, range 0.00-2.59; P < 0.01), and smaller ESVs (121 ± 70 vs. 166 ± 82; P = 0.02). However, there was no difference in core (9 ± 6 vs. 11 ± 6%), peri (9 ± 4 vs. 10 ± 4%), and total infarct size (18 ± 9 vs. 21 ± 9%; P > 0.05 for all comparisons); only transmural extent (P = 0.07) and infarct age (P = 0.06) tended to be larger in patients without early revascularization. CMR wall motion abnormalities are significantly better after revascularization; these differences are particularly marked later after infarction. The difference in scar size is more subtle and does not reach significance in this study.

Continuation of vitamin K antagonists as acceptable anticoagulation regimen in patients undergoing pulmonary vein isolation.

BACKGROUND: Recent studies have demonstrated that radiofrequency isolation of the pulmonary veins (PVI) is an effective treatment for symptomatic atrial fibrillation. Based on these positive results, non- pharmacological therapy has been incorporated in the guidelines for drug refractory atrial fibrillation, resulting in an increased popularity. The prevention of thromboembolic complications remains an important issue. METHODS: In January 2010, we adopted an anticoagulation strategy based on continuation of vitamin K antagonists (VKAs) and selective use of transoesophageal echocardiogram (TEE). We retrospectively analysed the results of this strategy in all patients referred for PVI treatment. VKAs were started for all patients 2 months prior to treatment. Discontinuation of oral anticoagulation was considered 3 months after treatment based on thromboembolic and bleeding risk profile. Bleeding and thromboembolic complications were registered during outpatient clinic follow-up up until 3 months. RESULTS: We performed 151 PVI procedures from January 2010 to March 2011. All patients were seen 6 weeks after discharge. No transient ischaemic accidents or ischaemic cerebrovascular incidents occurred pre-, peri- or postprocedure. Four (2.7%) procedures were complicated by tamponade requiring pericardiocentesis. CONCLUSIONS: Our data support the increasing evidence for continuation of periprocedural administration of VKAs complemented by a selective TEE approach as a safe therapy for thromboembolic complications.

Is T-wave alternans testing feasible in candidates for prophylactic implantable defibrillators?

AIMS: Previous studies have demonstrated that microvolt T-wave alternans (TWA) screening in patients with ischaemic and dilated cardiomyopathy is effective in identifying patients at high or low risk of sudden cardiac death. It remains unclear which percentage of potential recipients of an implantable cardioverter defibrillator (ICD) are able to perform TWA testing using an exercise protocol which is, at this moment, the golden standard. In this study, we evaluated the feasibility of TWA in the risk stratification of potential ICD recipients with ischaemic or dilated cardiomyopathy. METHODS AND RESULTS: Medical charts of 165 primary prevention ICD recipients were reviewed to decide if patients were able to perform a TWA exercise test or not. Reasons to waiver a test were: atrial fibrillation or flutter, pacemaker dependency, recent (cardiovascular) surgery (<1 month) and inability to exercise. Of the potential ICD recipients 35% had one or more of these contraindications and were therefore not suitable for testing. CONCLUSION: In several studies, TWA is a promising risk stratifier for predicting sudden cardiac death; however, in our population, 35% of the potential ICD candidates could not be tested. In order to fulfil its promise as a predictor for SCD, an alternative means to measure TWA needs to be evaluated.

Towards a better risk stratification for sudden cardiac death in patients with structural heart disease.

With the introduction of the implantable cardioverter defibrillator (ICD), patients can be protected against sudden cardiac death (SCD) due to ventricular arrhythmia (VA). Guidelines have been drawn up for selecting patients for primary and secondary prophylaxis. However, most ICD recipients today who receive an ICD for primary prevention will not experience a life-threatening VA requiring antitachypacing or shock therapy. Better risk stratification is desirable with efficacy, costs and complication rate in mind. An overview is presented of widely accepted and potentially valuable risk markers and the role they may play in better identifying candidates for ICD therapy. (Neth Heart J 2009;17:101-6.).

Acute success and short-term follow-up of catheter ablation of isthmus-dependent atrial flutter; a comparison of 8 mm tip radiofrequency and cryothermy catheters.

OBJECTIVES: To compare the acute success and short-term follow-up of ablation of atrial flutter using 8 mm tip radiofrequency (RF) and cryocatheters. METHODS: Sixty-two patients with atrial flutter were randomized to RF or cryocatheter (cryo) ablation. Right atrial angiography was performed to assess the isthmus. End point was bidirectional isthmus block on multiple criteria. A pain score was used and the analgesics were recorded. Patients were followed for at least 3 months. RESULTS: The acute success rate for RF was 83% vs 69% for cryo (NS). Procedure times were similar (mean 144+/-48 min for RF, vs 158+/-49 min for cryo). More applications were given with RF than with cryo (26+/-17 vs. 18+/-10, p<0.05). Fluoroscopy time was longer with RF (29+/-15 vs. 19+/-12 min, p<0.02). Peak CK, CK-MB and CK-MB mass were higher, also after 24 h in the cryo group. Troponin T did not differ. Repeated transient block during application (usually with cryoablation) seemed to predict failure. Cryothermy required significantly less analgesia (p<0.01), and no use of long sheaths (p<0.005). The isthmus tended to be longer in the failed procedures (p=0.117). This was similar for both groups, as was the distribution of anatomic variations. Recurrences and complaints in the successful patients were similar for both groups, with a very low recurrence of atrial flutter after initial success. CONCLUSIONS: In this randomized study there was no statistical difference but a trend to less favorable outcome with 8 mm tip cryocatheters compared to RF catheters for atrial flutter ablation. Cryoablation was associated with less discomfort, fewer applications, shorter fluoroscopy times and similar procedure times. The recurrence rate was very low. Cryotherapy can be considered for atrial flutter ablation under certain circumstances especially when it has been used previously in the same patient, such as in an AF ablation.

Challenging pacemaker implantation: persistent left superior vena cava with absent right superior vena cava.

A persistent left superior vena cava (PLSVC) in combination with an absent right superior vena cava (RSVC) is a rare congenital cardiovascular abnormality which is usually found by chance during pacemaker (PM) implantation. In this case we describe a PM implantation using right cephalic approach through PLSVC and coronary sinus (CS), with lead fixation in right atrium and a posterolateral branch of the CS.

Imaging of a coronary artery bypass graft during coronary sinus venography.

Retrograde coronary sinus perfusion to maintain viability during cardiac surgery means that a connection via the capillary system to the coronary arteries, and potentially bypass grafts, may be possible. Coronary sinus (CS) venography prior to resynchronisation therapy in this patient with previous bypass grafting was associated with visualisation of these grafts.

Magnetic navigation in AV nodal re-entrant tachycardia study: early results of ablation with one- and three-magnet catheters.

AIMS: Steering soft, flexible catheters using an external magnetic field could have advantages for heart catheterization, especially for therapy of tachyarrhythmias. Our aims were to assess the feasibility of magnetic navigation to Koch's triangle and reliable ablation of atrioventricular nodal re-entry tachycardia (AVNRT) with a magnetic catheter. METHODS AND RESULTS: Consecutive patients with AVNRT were mapped and ablated with a magnetically enabled catheter (Helios I or II), with, respectively, one and three magnets at the tip. The catheter was remotely advanced with the Cardiodrive system and orientated with the Navigant control system. After initial positioning with the external magnets, adjustment was made in 5 degrees steps. Success rates, procedure, and fluoroscopy times were analysed, and compared with a local contemporary series of conventional AVNRT ablations. Magnetic navigation was feasible in all 20 patients. Targets were easily reached. Catheters remained stable in position during accelerated junctional rhythms. Ablation was successful in 18/20 procedures (90%). No significant complications occurred. Median patient fluoroscopy time was 12 min, median physician fluoroscopy time was 4 min. Fluoroscopy times tended to be shorter than that in the conventionally treated group. Procedure duration decreased significantly over time, median procedure time was similar to that in the conventional group. CONCLUSION: AVNRT can be successfully mapped and ablated using magnetic navigation. A learning curve was evident, unrelated to catheter type, but to increasing operator experience. Physician radiation times were one-third of patient times. No complications occurred. Procedure time is comparable with that of conventional ablation.

Anticoagulation in atrial fibrillation and flutter.

Atrial fibrillation and atrial flutter are important risk factors for stroke. Based on a literature search, pathogenesis of thromboembolism, risk assessment in patients, efficacy of anticoagulation therapy and its alternatives are discussed. Special emphasis is put on issues like paroxysmal atrial fibrillation, atrial flutter and anticoagulation surrounding catheter ablation and cardioversion. A strategy for anticoagulation around the time of pulmonary vein ablation is suggested.

Pulmonary vein antrum isolation guided by phased-array intracardiac echocardiography: A third way to do PV ablation.

BACKGROUND: Pulmonary vein isolation (PVI) has emerged as an important strategy in the treatment of patients with atrial fibrillation (AF). The two most frequently used techniques are segmental PVI and left atrial circumferential ablation. AIM: To describe and discuss pulmonary vein antrum isolation guided by phased-array intracardiac echocardiography (ICE) as an alternative approach, and to present initial results. METHODS: Patients with symptomatic AF were included. The antra (the larger circumferential area around the PVs) were isolated guided by ICE. ICE was also used to titrate the ablation energy. RESULTS: 38 patients (3 with persistent AF) were included. Of the 35 patients with paroxysmal AF, 24 are without recurrences, and in six the incidence of paroxysms was significantly reduced after one procedure and a mean follow-up of 201 days. No major complications occurred. CONCLUSION: Pulmonary vein antrum isolation guided by ICE is a promising technique in AF ablation and has the potential to avoid severe complications.