Multi-catheter cryotherapy for the treatment of resistant accessory pathways.

OBJECTIVE: To investigate the utility of simultaneous multi-catheter cryotherapy for the treatment of APs that were previously resistant to standard radiofrequency (RF) catheter ablation. BACKGROUND: Catheter ablation is established in the treatment of accessory pathways (AP), with high rates of permanent procedural success with a single attempt. However, there are still instances of acute procedural failure and AP recurrences with standard RF and cryotherapy methods. METHODS: Seven consecutive cases of pre-excitation syndromes with prior failed RF catheter ablation had the novel treatment. Cryotherapy was delivered using two 8 mm tip focal cryoablation catheters (Freezor® Max, Medtronic, Minneapolis, Minnesota, USA). RESULTS: Accessory pathway localisation was septal in 5 cases, left posterolateral in 1, right lateral in 1. In all cases, ablation of the AP was acutely successful with no procedural complications. Median procedure and fluoroscopy durations were 199 and 35 min, sequentially. Median Procedure duration fell significantly in the second half of series (174 min) compared to the first half (233 min, P = 0.05). One patient had evidence of a recurring AP conduction with pre-excitation at 5-week follow up. After a median follow up of 66.8+-6.5 months, 6 out of 7 patients remained asymptomatic and free of pre-excitation. CONCLUSION: Simultaneous multi-catheter cryotherapy is feasible, safe and can provide definitive cure of accessory pathways that were previously resistant to standard radiofrequency ablation. Further study is required in the assessment of this novel form of advanced cryotherapy to treat complex and resistant arrhythmias.

Randomized comparison of oesophageal protection with a temperature control device: results of the IMPACT study.

AIMS: Thermal injury to the oesophagus is an important cause of life-threatening complication after ablation for atrial fibrillation (AF). Thermal protection of the oesophageal lumen by infusing cold liquid reduces thermal injury to a limited extent. We tested the ability of a more powerful method of oesophageal temperature control to reduce the incidence of thermal injury. METHODS AND RESULTS: A single-centre, prospective, double-blinded randomized trial was used to investigate the ability of the ensoETM device to protect the oesophagus from thermal injury. This device was compared in a 1:1 randomization with a control group of standard practice utilizing a single-point temperature probe. In the protected group, the device maintained the luminal temperature at 4°C during radiofrequency (RF) ablation for AF under general anaesthesia. Endoscopic examination was performed at 7 days post-ablation and oesophageal injury was scored. The patient and the endoscopist were blinded to the randomization. We recruited 188 patients, of whom 120 underwent endoscopy. Thermal injury to the mucosa was significantly more common in the control group than in those receiving oesophageal protection (12/60 vs. 2/60; P = 0.008), with a trend toward reduction in gastroparesis (6/60 vs. 2/60, P = 0.27). There was no difference between groups in the duration of RF or in the force applied (P value range= 0.2-0.9). Procedure duration and fluoroscopy duration were similar (P = 0.97, P = 0.91, respectively). CONCLUSION: Thermal protection of the oesophagus significantly reduces ablation-related thermal injury compared with standard care. This method of oesophageal protection is safe and does not compromise the efficacy or efficiency of the ablation procedure.

Multi-catheter cryotherapy compared with radiofrequency ablation in long-standing persistent atrial fibrillation: a randomized clinical trial.

AIMS: Restoring sinus rhythm (SR) by ablation alone is an endpoint used in radiofrequency (RF) ablation for long-standing persistent atrial fibrillation (AF) but not with cryotherapy. The simultaneous use of two cryotherapy catheters can improve ablation efficiency; we compared this with RF ablation in chronic persistent AF aiming for termination to SR by ablation alone. METHODS AND RESULTS: Consecutive patients undergoing their first ablation for persistent AF of >6 months duration were screened. A total of 100 participants were randomized 1:1 to multi-catheter cryotherapy or RF. For cryotherapy, a 28-mm Arctic Front Advance was used in tandem with focal cryoablation catheters. Open-irrigated, non-force sensing catheters were used in the RF group with a 3D mapping system. Pulmonary vein (PV) isolation and non-PV triggers were targeted. Participants were followed up at 6 and 12 months, then yearly. Acute PVI was achieved in all cases. More patients in the multi-catheter cryotherapy group were restored to SR by ablation alone, with a shorter procedure duration. Sinus rhythm continued to the last available follow-up in 16/49 patients (33%) in the multi-catheter at 3.0 ± 1.6 years post-ablation and in 12/50 patients (24%) in the RF group at 4.0 ± 1.2 years post-ablation. The yearly rate of arrhythmia recurrence was similar. CONCLUSION: Multi-catheter cryotherapy can restore SR by ablation alone in more cases and more quickly than RF ablation. Long-term success is difficult to achieve by either methods and is similar with both.

The association between serum angiogenin and osteopontin levels and coronary collateral circulation in patients with chronic total occlusion.

OBJECTIVE: A well-developed coronary collateral circulation lowers both in-hospital and long-term morbidity and mortality limiting the infarct. Angiogenin (AGN) and osteopontin (OPN) are known to be potent inducers of angiogenesis. The aim of the present study was to investigate the relationship between serum ANG and OPN levels and collateral filling grade in subjects with stable coronary artery disease (SCAD). METHODS: A total of 122 age- and gender-matched consecutive patients who were found to have total occlusion (n=70) and no significant stenosis in epicardial coronary arteries (n=52) who underwent coronary angiography due to SCAD between January 2015 and July 2017 were included in the study. AGN and OPN levels were measured using enzyme linked immunosorbent assay. Coronary collateral circulation was graded using Rentrop's classification of collateral filling. RESULTS: A total of 52 patients (61.60±11.78 years, 61.5% male) without significant epicardial coronary artery stenosis and 70 patients (62.87±8.24 years, 65.7% male) with totally occluded coronary arteries were included in the study. Subjects with total occlusion had significantly higher levels of AGN [122.00 (79.00-623.00) pg/mL vs. 98.00 (18.00-160.00) pg/mL, p<0.001] and OPN [1863.50 (125.00-6500.00) pg/mL vs. 451.00 (112.00- 1850.00) pg/mL, p<0.001] than those without significant stenosis. In addition, AGN [127.00 (87.00-623.00) pg/mL vs. 110.00 (79.00-188.00) pg/mL, p=0.011] and OPN [2681.00 (126.00-6500.00) pg/mL vs. 649.00 (125.00-4255.00) pg/mL, p=0.001] levels were significantly higher in patients with better developed collaterals. Serum AGN and OPN levels were found to be significantly associated with coronary collateral development. CONCLUSION: AGN and OPN are associated with better developed coronary collateral circulation and may have therapeutic implications for the promotion of coronary collateral development.

Long-term outcomes of pulmonary vein isolation using second-generation cryoballoon during atrial fibrillation ablation.

BACKGROUND: Currently available second-generation cryoballoon (CB2) is accepted as an effective and safe tool for pulmonary vein isolation (PVI). Although much more data exist about 1-year outcomes of CB2 ablation, data on long-term outcomes are scarce. OBJECTIVE: We aimed to assess the long-term outcomes of PVI using CB2 in a large-scale symptomatic atrial fibrillation (AF) population at our tertiary referral center. METHODS: In this nonrandomized prospective observational study, a total of 486 patients with paroxysmal (71%) or persistent (29%) AF who underwent index PVI using CB2 at our hospital between January 2013 and June 2017 were enrolled. Atrial tachyarrhythmia (ATa)-free survival was defined as the absence of AF, atrial flutter, or atrial tachycardia recurrence ≥30 s following a 3 months blanking period. Predictors of recurrence were evaluated by univariate and multivariate Cox proportional hazards regression models. RESULTS: Acute procedural success rate was 99.8% (1898/1902 PVs). Mean procedural and fluoroscopy time were 64.9 ± 9.2 and 12.1 ± 2.6, respectively. At median 39 (interquartile range: 26-56) months follow-up, ATa-free survival was 78.6% after a single procedure (280/345 [81.2%] for paroxysmal AF vs. 102/141 [72.3%] for persistent AF, P = .019) and 84.4% after a mean 1.48 ± 0.42 ablations. Cox regression analysis showed that left atrium diameter, duration of AF history, and early ATa recurrence were found as the independent predictors of late recurrence. Phrenic nerve palsy was observed in 17 (3.5%) patients. CONCLUSIONS: CB2-based PVI is effective to maintain sinus rhythm in a significant proportion of paroxysmal and persistent AF patients with an acceptable complication rate at long-term follow-up.

Half a century of continuous pacing: a living witness to the evolution of a technology.

To chart the development of pacing technology and its pitfalls we present the experience of a patient who has benefitted from it but also suffered as a result of it from its earliest days. A 53-year-old physician was referred to us with obstruction of the superior and inferior vena cava on a background of more than 50 years of continuous ventricular pacing and 24 previous pacemaker-related interventions. In a single surgical procedure, his existing pacing system and redundant leads were extracted, the superior vena cava was reconstructed, and a new biventricular pacing system with epicardial leads was implanted. Pacemakers can maintain life and preserve the quality of life for many decades. The quality of this therapy has improved due to advances in the technology and in techniques. Maintaining safe pacing in the very long term requires labour, patience, and ingenuity.

Cardiac arrest following protamine administration: a case series.

AIMS: Protamine sulfate is commonly used to reverse the action of heparin after catheter ablation procedures. Serious protamine-related adverse effect is rare, but its recognition and appropriate management by electrophysiologists and intensivists is important. Direct ventricular fibrillation (VF) soon after a slow infusion of protamine has not been clearly described. METHODS AND RESULTS: We examined the records of all patients who suffered apparent adverse events after protamine administration in our electrophysiology lab from 2013 to 2018. We describe a series of three patients, all of whom suffered a precipitous fall in arterial pressure followed by VF within minutes after administration of protamine following ablation for atrial fibrillation. The same supplier of protamine was used in all three cases, but they were from different batches. Serum tryptase levels were measured in all cases, immediately post-cardiac arrest and at 2- and 6-h post-event. Immunoglobulin levels were not measured. Two patients recovered after aggressive supportive therapy; the third died despite similar support. CONCLUSION: We have encountered three cases of profound hypotension followed by VF soon after administration of protamine. Although protamine is safe in a large majority of patients, these adverse events have led our centre to exercise greater selectivity and caution in its use.

Impact of anatomical features of the left atrial appendage on outcomes after cryoablation for atrial fibrillation.

AIMS: Pulmonary vein isolation (PVI) using cryoballoon has been accepted as a safe and effective method for treatment of atrial fibrillation (AF). Despite advances in catheter-based technologies, some patients still experience AF recurrence. In this study, we aimed to compare left atrial appendage (LAA) morphology in AF patients and subjects with sinus rhythm and also investigate the association between LAA morphology and success of PVI using cryoballoon in subjects with AF. METHODS: In this prospective study, 359 AF patients who underwent pre-ablation computed tomographic angiography (CTA) scan between January 2013-March 2016 were included as the patient group. 100 age and gender-matched subjects in sinus rhythm who had no AF episodes in 24-h Holter monitoring that underwent CTA were included as the control group. RESULTS: Non-chicken wing LAA morphology was more common in AF patients (p < 0.001). LAA was significantly deeper (p < 0.001) and short-axis diameter of LAA orifice and LAA orifice area were significantly larger (p < 0.001) in AF patients. Low take-off type morphology of LAA was more common in controls compared to AF patients (p = 0.006). At a median follow-up of 37 months, only longitudinal-axis left atrial diameter on CT (p = 0.003) and cauliflower-type LAA morphology (p = 0.004) were independent predictors of AF recurrence. CONCLUSION: This is the first study in the literature that investigates the relationship between anatomical variations of LAA and AF recurrence following cryoablation. Our findings demonstrate that cauliflower-type LAA morphology is associated with two-fold increased risk of AF recurrence.

Remanufactured circular mapping catheters: safety, effectiveness and cost.

BACKGROUND: The use of remanufactured single-use devices (SUDs), including cardiac electrophysiology catheters, has become established in the USA and other health care systems but without much published scientific evaluation on the relative safety or efficacy of these devices. In the United Kingdom (UK), the use of remanufactured SUDs has not been routine. We performed a structured evaluation of the safety and efficacy of a remanufactured circular mapping catheter (Stryker® remanufactured Lasso NAV 2515) during its introduction in our centre. METHODS: We prospectively evaluated the performance of a remanufactured circular mapping catheter in 100 consecutive patients undergoing an AF ablation. Operator feedback was obtained, assessing the device appearance, ease of use and function. As an indirect measurement of efficacy, acute procedure metrics were compared to those in 100 propensity-matched cases performed by the same operators using a new device. Cost savings were calculated. RESULTS: No complication occurred in association with the remanufactured device. There was one reported failure of device malfunction-the flexion-extension mechanism of a remanufactured catheter and none in the matched-control group. There was satisfactory communication with the electro-anatomic mapping system. Ease of use of the remanufactured catheter was reported to be similar to a newly manufactured device. Procedural duration was similar with remanufactured devices and matched controls. With 100 cases using the remanufactured device, cost savings amounted to £30,444. CONCLUSIONS: The use of remanufactured circular mapping catheters is safe, efficient and reliable. Widespread use of remanufactured SUDs offers the possibility of significant economic benefit.

Pulmonary vein orientation is independently associated with outcomes following cryoballoon-based atrial fibrillation ablation.

AIMS: Several studies have investigated the influence of pulmonary vein (PV) anatomy on outcomes of atrial fibrillation (AF) ablation. We aimed to evaluate the relationship between PV orientation and AF-free survival following cryoablation. METHODS: 160 patients scheduled for cryoablation between September 2012-March 2014 were included. Patients underwent a pre-procedural cardiac CT scan with retrospective ECG gating. PV orientation was assessed according to the position of the PV orifice relative to the sagittal plane with reference to coronal and horizontal planes. RESULTS: 160 patients (57 ±â€¯9 years, 54% male, 33% persistent AF) were included and followed for a median of 17 (12-36) months. Excluding a blanking period of 3 months, freedom from AF after a single ablation procedure was 76%. Ventral-caudal left upper PV (p = 0.044) and ventral-caudal left lower PV orientation (p = 0.001) were more common in patients with AF recurrence. In multivariate Cox regression analysis, only left lower PV orientation [particularly dorsal-caudal (HR: 3.447, 95% CI: 1.180-10.070, p = 0.024) and ventral-caudal (HR: 3.391, 95% CI: 1.088-10.571, p = 0.035) orientations compared to dorsal-cranial orientation] as well as LA diameter (HR: 3.420, 95% CI: 1.809-6.465, p < 0.001) were significantly associated with AF recurrence. CONCLUSION: This is the first study to demonstrate the impact of PV orientation on prediction of AF recurrence following cryoablation. Preprocedural assessment of PV orientation may modify operator preferences on treatment strategies in AF.

Platelet Toll-like receptor and its ligand HMGB-1 expression is increased in the left atrium of atrial fibrillation patients.

BACKGROUND: Atrial fibrillation(AF) is the most common sustained arrhythmia. Its most feared sequelae are stroke and peripheral thromboembolism due to atrial thrombi formation. Mechanisms underlying the relationship between platelet activation and left atrial thrombi have not been clearly elucidated yet. We aimed to investigate whether immune-mediated platelet activation occurred in AF patients in this cross-sectional study. METHODS: Persistent and paroxysmal AF patients who underwent cryoballoon-based AF ablation between March 2015 and July 2016 were included as the patient group. Patients without AF in whom transseptal puncture was performed at the same period for purposes other than AF ablation were included as the control group. Peripheral and left atrial blood samples were obtained for determination of platelet Toll-like receptor(TLR)-2, TLR-4 and high mobility group box-1(HMGB-1) expression levels. RESULTS: A total of 75 subjects (53 patients with AF and 22 control subjects) [mean: 60.33 (SD: 6.14) years, 57.33% male] were included. Left atrial and peripheral TLR-2, 4 and HMGB-1 expression levels were significantly higher in the patient group when compared to the controls. Left atrial platelet TLR-2 and TLR-4 expression and serum HMGB-1 levels were higher in persistent AF patients compared to paroxysmal AF patients. In the patient group, left atrial expression of TLR-2, 4 and HMGB-1 were significantly higher than the peripheral expression levels. CONCLUSION: Findings of our study suggest evidence for immune-mediated platelet activation in the left atria of AF patients.

Echocardiographic assessment of regional right ventricular systolic function using two-dimensional strain echocardiography and evaluation of the predictive ability of longitudinal 2D-strain imaging for pulmonary arterial hypertension in systemic sclerosis patients.

Systemic sclerosis (SSc) is a generalized connective tissue disorder, and SSc patients are at risk of developing pulmonary arterial hypertension (PAH). The aims of this study are to evaluate the right ventricular regional systolic function using two-dimensional speckle-tracking echocardiography (2D STE) and to determine the predictive ability of peak longitudinal systolic strain (PLSS) at the RV lateral wall for PAH in SSc patients. 80 SSc patients (mean age 51 ± 12 years) were included in the study. Echocardiography and 2D STE were performed at baseline and after 12 months. RHC was performed only in SSc patients with clinical indications. PLSS at the apical segment of the RV free wall was significantly impaired in PAH patients compared with non-PH patients (-14.6 ± 5.9 vs. - 22.2 ± 7.5%, p = 0.034). PLSS at the basal, mid, and apical segments of the RV free wall was lower in both groups at follow-up compared to baseline, but the drop in strain values was statistically significant only in the non-PH group (p < 0.05). Right atrial area (OR 1.758; p = 0.023), peak tricuspid regurgitation velocity (OR 24.23; p = 0.011) and PLSS at the apical segment of the RV lateral wall (OR 2.47; p = 0.005) were independent predictors of PAH. A cut-off value of - 14.48% PLSS at the apical segment of the RV lateral wall resulted in 100% specificity for predicting PAH in SSc patients. RV pressure overload affects RV systolic function as manifested by impaired RV longitudinal deformation. Evaluating RV regional systolic function with 2D STE could be useful as an additional echocardiographic parameter for screening PAH in SSc patients.

Left ventricular lead misplacement discovered a decade after cardiac resynchronization therapy-defibrillator implantation: a case report.

INTRODUCTION: Satisfactory left ventricular (LV) lead placement into the coronary sinus (CS) can be achieved in the majority of patients but there are still instances of acute failure most often due to anatomical differences, for example due to tortuous CS anatomy. Chronic LV lead misplacement and its delayed discovery is not a common scenario. It is unclear if chronic dual right ventricular pacing can hasten the progression of heart failure. CASE PRESENTATION: A 73-year-old lady presented to our cardiac centre with severe heart failure. She had non-ischaemic dilated cardiomyopathy with underlying left bundle branch block and a cardiac resynchronization therapy-defibrillator device in situ for the past decade. She also had a chronic pericardial effusion of unknown aetiology. Whilst the patient was being treated for acute heart failure, it was noted on patient telemetry that the QRS morphology for supposed bi-ventricular pacing was unusual. This led to a lateral chest radiograph and a CS venogram to be performed, both of which confirmed that the LV lead was in fact not in the CS. Plans were made to place a new LV lead but unfortunately the patient continued to clinically deteriorate despite maximal treatment and died before this could be performed. DISCUSSION: It is only with thorough review of the electrocardiographic data and chest radiography that led to the discovery of chronic LV lead misplacement. This case illustrates the importance of expert review of radiographic imaging and electrocardiographic data in patients with implanted cardiac devices.

Entrapment of focal atrial tachycardia using cryoballoon ablation; Sinus rhythm in the left atrium and ongoing atrial tachycardia in the left atrial appendage.

Left atrial appendage (LAA) is a well-known source of focal atrial tachycardias (AT). Although radio-frequency (RF) energy is the most commonly used technique in such cases, there was an option other than epicardial approach when RF technique fails. Cryoballoon technology is primarily developed to be used for pulmonary vein isolation (PVI). Also, there was no report regarding the isolation of LAA by using cryo-balloon in patients with focal AT. In this case, for the first time in the literature, we successfully isolated the LAA because of failed attempts of RF ablation for focal AT in whom the surface electrogram showed a sinus rhythm while arrhythmia continues inside the LAA.