Therapy of ventricular arrhythmias in patients suffering from isolated left ventricular non-compaction cardiomyopathy.

AIMS: Non-compaction cardiomyopathy (NCCM) is associated with high rates of mortality and morbidity. Knowledge regarding risk stratification, arrhythmogenesis, therapy, and prognosis is limited. The aim of this study was to analyse the outcome of patients suffering from NCCM and ventricular arrhythmias (VAs) focusing on a treatment with implantable cardioverter-defibrillator (ICD) therapy and catheter ablation. METHODS AND RESULTS: We conducted a multicentre observational study on 18 patients with NCCM, who underwent ICD implantation for secondary (n = 12) and primary (n = 6) prevention. In patients with multiple symptomatic episodes of VAs catheter ablation was performed. During a follow-up of 62 ± 42 months, 12 patients (67%) presented with appropriate ICD therapies [ventricular tachycardia (VT): n = 8; ventricular fibrillation (VF): n = 4; VT/VF: n = 3]. Ten patients underwent catheter ablation for VT/VF. Solely endocardial ablation was conducted in eight patients, and in two patients endo- and epicardial ablation was performed within the same procedure. Acute procedural success was achieved in 9/10 patients. Ventricular tachycardia recurrence was observed in two patients and the median arrhythmia free interval was 9.5 months (interquartile range 5.3-21 months). One patient underwent reablation, four patients died due to the underlying NCCM, and one patient received a left ventricular assist device. CONCLUSION: Ventricular arrhythmias are common in patients suffering from NCCM and ICD therapy may be effective for primary and secondary prevention. In our cohort, consisting of patients with multiple VA episodes and recurrent ICD therapy, catheter ablation offered a safe and effective therapeutically option.

Catheter ablation of recurrent scar-related ventricular tachycardia using electroanatomical mapping and irrigated ablation technology: results of the prospective multicenter Euro-VT-study.

INTRODUCTION: Ventricular tachycardia (VT) late after myocardial infarction is an important contributor to morbidity and mortality. This prospective multicenter study assessed the efficacy and safety of electroanatomical mapping in combination with open-saline irrigated ablation technology for ablation of chronic recurrent mappable and unmappable VT in remote myocardial infarction. METHODS AND RESULTS: In 8 European institutions, 63 patients (89% males) were enrolled in the study. All patients had remote myocardial infarction and presented with a median number of 17 (range 1-380) VTs in the preceding 6 months. Incessant VT was present in 14 patients (22%). Left ventricular ejection fraction measured 30 +/- 13%. A mean of 3 VTs were targeted per patient and 22% of all patients had only unmappable VT. The mean follow-up period was 12 +/- 3 months. A total of 164 VTs were targeted during catheter ablation. Ablation was acutely successful in 51 patients (81%). One patient (1.5%) experienced a major complication with degeneration of VT into ventricular fibrillation necessitating cardiopulmonary resuscitation maneuvers. However, no death occurred acutely or within the first 30 days after catheter ablation. During the follow-up, 19 of the initially successful ablated patients (37%) and 31 of all ablated patients (49%) developed some type of VT recurrence. CONCLUSIONS: The results of this multicenter study demonstrate the high acute success rate and a low complication rate of irrigated tip catheter ablation of all clinical relevant VTs in remote myocardial infarction. However, during the follow-up a relevant number of recurrences occurred.

Transvenous cardiac resynchronization therapy in complex congenital heart diseases: dextrocardia with transposition of the great arteries after Mustard operation.

Cardiac resynchronization therapy revealed first promising results in patients with a congenital heart disease and a systemic right ventricle. Contrast-enhanced magnetic resonance imaging showed accessibility of the coronary sinus in an 18-year-old male patient with mirror dextrocardia, d-transposition of the great arteries and ventricular septal defect (VSD) after Mustard operation and VSD patch closure. In literatures, transvenous lead placement is discussed in this anatomical setting, with opposed position of the ventricular leads and reliable lead characteristics.

Catheter Ablation for Atrial Fibrillation in Adults With Congenital Heart Disease: Lessons Learned From More Than 10 Years Following a Sequential Ablation Approach.

OBJECTIVES: This study aimed to evaluate the impact, safety, and success of atrial fibrillation (AF) ablation in adults with congenital heart disease (ACHD) transferring ablation strategies established in normal hearts. BACKGROUND: AF is an emerging arrhythmia in ACHD. METHODS: Fifty-seven consecutive ACHD (median age 51.1 ± 14.8 years) with drug-refractory AF were analyzed who underwent catheter ablation between 2004 and 2017. CHD was classified according to its complexity into mild (61.4%), moderate (17.5%), and severe (21.1%) lesions. AF ablation was performed in 104 procedures following a sequential ablation approach. RESULTS: Of the 57 patients, 30 underwent corrective surgery, 6 underwent palliative surgery, 5 had catheter interventions, and 16 were natural survivors. Follow-up was available for all patients (median 41 ± 36 months). The median duration of cyanosis was 9.2 ± 19.7 years, and the time of volume or pressure overload prior to corrective surgery or intervention was 26.1 ± 21.2 years and 18.1 ± 15.8 years, respectively. The Kaplan-Meier estimate for arrhythmia-free survival following the index ablation procedure was 63% for 1 year and 22% for 5 years. Performing subsequent ablation procedures (2.0 ± 0.5), the Kaplan-Meier estimate significantly improved, with 99% for 1 year and 83% for 5 years (p < 0.01). Five patients died during follow-up due to their underlying CHD condition or underwent transplantation. CONCLUSIONS: AF ablation strategies established in normal hearts can be transferred to ACHD. The treatment is safe and effective with acceptable long-term results. Varying anatomical pre-conditions and the heterogeneous population itself are challenging and contribute toward a higher reablation rate. Therefore, AF ablation in ACHD should be reserved for dedicated and highly specialized teams.

The best of two worlds? Pulmonary vein isolation using a novel radiofrequency ablation catheter incorporating contact force sensing technology and 56-hole porous tip irrigation.

AIMS: This study aimed to evaluate feasibility and safety as well as 1-year clinical outcome of pulmonary vein isolation (PVI) using a unique radiofrequency ablation catheter ("Thermocool SmartTouch SurroundFlow"; STSF) incorporating both, contact force (CF) sensing technology and enhanced tip irrigation with 56 holes, in one device. METHODS: A total of 110 patients suffering from drug-refractory atrial fibrillation underwent wide area circumferential PVI using either the STSF ablation catheter (75 consecutive patients, study group) or a CF catheter with conventional tip irrigation ("Thermocool SmartTouch", 35 consecutive patients, control group). For each ablation lesion, a target CF of ≥ 10-39 g and a force time integral (FTI) of > 400 g s was targeted. RESULTS: Acute PVI was achieved in all patients with target CF obtained in > 85% of ablation points when using either device. Mean procedure time (131.3 ± 33.7 min in the study group vs. 133.0 ± 42.0 min in the control group; p = 0.99), mean fluoroscopy time (14.0 ± 6 vs. 13.5 ± 6.6 min; p = 0.56) and total ablation time were not significantly different (1751.0 ± 394.0 vs. 1604.6 ± 287.8 s; p = 0.2). However, there was a marked reduction in total irrigation fluid delivery by 51.7% (265.52 ± 64.4 vs. 539.6 ± 118.2 ml; p < 0.01). The Kaplan-Meier estimate 12-month arrhythmia-free survival after the index procedure following a 3-month blanking period was 79.9% (95% CI 70.4%, 90.4%) for the study group and 66.7% for the control group (95% CI 50.2%, 88.5%). This finding did not reach statistical significance (p = 0.18). Major complications occurred in 2/75 patients (2.7%; one pericardial tamponade and one transient ischemic attack) in the study group and no patient in the control group (p = 18). CONCLUSION: PVI using the STSF catheter is safe and effective and results in beneficial 1-year clinical outcome. The improved tip irrigation leads to a significant reduction in procedural fluid burden.

Electroanatomic mapping and catheter ablation of breakthroughs from the right atrium to the superior vena cava in patients with atrial fibrillation.

BACKGROUND: The superior vena cava (SVC) is one of the sources of ectopies that can initiate atrial fibrillation (AF). We investigated by radiofrequency ablation the electrophysiological characteristics of the junction of the right atrium (RA) and the SVC and the feasibility of electrical disconnection of the SVC from the RA. METHODS AND RESULTS: Sixteen patients with paroxysmal AF after pulmonary vein isolation underwent electroanatomic mapping at the RA-SVC junction during sinus rhythm. Mapping showed sharp potentials (SVC potentials) inside the SVC. Activation spread from the earliest SVC potential (breakthrough) to the rest of the SVC. SVC potentials were found over a large amount of the circumference, suggesting widespread muscle coverage of the SVC. Breakthroughs from the RA to SVC were located anteriorly, laterally, posteriorly, and septally in 3, 4, 10, and 6 patients, respectively. The number of breakthroughs was 1.4+/-0.5 per patient. Radiofrequency energy was applied with the end point of electrical disconnection. All breakthroughs were eliminated with 3.1+/-1.7 applications per breakthrough without complications. CONCLUSIONS: SVC potentials can be recorded inside the SVC. There are specific breakthroughs from the RA to the SVC that can be identified by electroanatomic mapping. The electrical disconnection of the SVC from the RA is feasible.

Electroanatomic substrate of idiopathic left ventricular tachycardia: unidirectional block and macroreentry within the purkinje network.

BACKGROUND: An abnormal potential (retroPP) from the left posterior Purkinje network has been demonstrated during sinus rhythm (SR) in some patients with idiopathic left ventricular tachycardia (ILVT). We hypothesized that this potential can specifically be identified and be a critical substrate for ILVT. METHODS AND RESULTS: In 9 patients with ILVT and 6 control patients who underwent mapping of the left ventricle during SR using 3-dimensional electroanatomic mapping, an area with retroPP was found within the posterior Purkinje fiber network only in patients with ILVT. The earliest and latest retroPP was 185.4+/-57.4 and 465.2+/-37.3 ms after Purkinje potential; in the other patient with ILVT, an entire left ventricle mapping demonstrated a slow conduction area and passive retrograde activation along the posterior fascicle during ILVT. ILVT was noninducible in 3 patients after SR mapping. Diastolic potentials critical for ILVT during ILVT coincided with the earliest retroPP during SR in 7 patients. Mechanical termination of ILVT occurred in 5 patients. A single radiofrequency pulse was applied at the site with mechanical translation in 5 patients and the site with diastolic potential in 2 patients, and 3 radiofrequency pulses were delivered to the site with the earliest retroPP in the other 3 patients without inducible ILVT after SR mapping. No ILVT was inducible during control stimulation, and none recurred during follow-up of 9.1+/-5.1 months. CONCLUSION: In patients with ILVT, abnormal retroPP within the posterior Purkinje fiber network is a common finding. The earliest retroPP critical for ILVT substrate can be used for guiding successful ablation.

Characterization of reentrant circuits in left atrial macroreentrant tachycardia: critical isthmus block can prevent atrial tachycardia recurrence.

BACKGROUND: Left atrial macroreentrant tachycardia (LAMRT) has not been characterized in detail. METHODS AND RESULTS: Twenty-eight patients with LAMRT, including 4 patients with ablated typical atrial flutter (AFL), underwent electroanatomic mapping of the left atrium (LA) between February 1999 and October 2001. LA maps were performed during LAMRT in 26 patients and during sinus rhythm in 2 patients. Electrically silent areas or continuous lines of double potentials were identified as acquired anatomic barriers in all patients. In 23 of 26 patients with LAMRT mapping, 42 reentry circuits with a protected isthmus were identified. The isthmus was 11.8+/-5.9 mm wide, with the maximal amplitude of 0.07 to 3.61 mV. Radiofrequency pulses terminated all LAMRTs in 23 patients and resulted in conduction block across the isthmus in 20 patients. In 2 patients with sinus mapping, all identified isthmuses were ablated. Additionally, AFL was induced and ablated in 6 patients. Atrial tachycardia recurred in 4 patients: 3 patients without validated block across the isthmus presented with recurrence of the same LAMRT, and 1 patient without ablated cavotricuspid isthmus presented with AFL. All tachycardias were abolished during a second procedure. Of 25 patients with identified isthmuses, 20 patients were without atrial arrhythmia and 5 had only atrial fibrillation during a median follow-up of 14 months. CONCLUSION: The reentry circuit with a protected isthmus can be identified in 89% patients with LAMRT by electroanatomic mapping. The isthmuses were amenable to radiofrequency applications in most patients. No atrial tachycardia recurred in any patients with isthmus block.

Primary prevention of sudden cardiac death in idiopathic dilated cardiomyopathy: the Cardiomyopathy Trial (CAT).

BACKGROUND: Patients with idiopathic dilated cardiomyopathy (DCM) and impaired left ventricular ejection fraction have an increased risk of dying suddenly. METHODS AND RESULTS: Patients with recent onset of DCM (< or =9 months) and an ejection fraction < or =30% were randomly assigned to the implantation of an implantable cardioverter-defibrillator (ICD) or control. The primary end point of the trial was all-cause mortality at 1 year of follow-up. The trial was terminated after the inclusion of 104 patients because the all-cause mortality rate at 1 year did not reach the expected 30% in the control group. In August 2000, the vital status of all patients was updated by contacting patients, relatives, or local registration offices. One hundred four patients were enrolled in the trial: Fifty were assigned to ICD therapy and 54 to the control group. Mean follow-up was 22.8+/-4.3 months, on the basis of investigators' follow-up. After 1 year, 6 patients were dead (4 in the ICD group and 2 in the control group). No sudden death occurred during the first and second years of follow-up. In August 2000, after a mean follow-up of 5.5+/-2.2 years, 30 deaths had occurred (13 in the ICD group and 17 in the control group). Cumulative survival was not significantly different between the two groups (93% and 80% in the control group versus 92% and 86% in the ICD group after 2 and 4 years, respectively). CONCLUSIONS: This trial did not provide evidence in favor of prophylactic ICD implantation in patients with DCM of recent onset and impaired left ventricular ejection fraction.

Repetitive monomorphic ventricular tachycardia originating from the aortic sinus cusp: electrocardiographic characterization for guiding catheter ablation.

OBJECTIVES: We sought to investigate the electrocardiographic (ECG) characteristics for guiding catheter ablation in patients with repetitive monomorphic ventricular tachycardia (RMVT) originating from the aortic sinus cusp (ASC). BACKGROUND: Repetitive monomorphic ventricular tachycardia can originate from the right ventricular outflow tract (RVOT) and ASC in patients with a left bundle branch block (LBBB) morphology and an inferior axis. METHODS: Activation mapping and ECG analysis was performed in 15 patients with RMVT or ventricular premature contractions. The left main coronary artery (LMCA) was cannulated as a marker and for protection during radiofrequency delivery if RMVT originated from the left coronary ASC. RESULTS: During arrhythmia, the earliest ventricular activation was recorded from the superior septal RVOT in eight patients (group 1) and from the ASC in the remaining seven patients (group 2). The indexes of R-wave duration and R/S-wave amplitude were significantly lower in group 1 than in group 2 (31.8+/-13.5% vs. 58.3+/-12.1% and 14.9+/-9.9% vs. 56.7+/-29.5%, respectively; p < 0.01), despite similar QRS morphology. In five patients from group 2, RMVT originated from the left ASC, with a mean distance of 12.2+/-3.2 mm (range 7.3 to 16.1) below the ostium of the LMCA. In the remaining two patients, the RMVT origin was in the right ASC. All arrhythmias were successfully abolished. None of the patients had recurrence or complications during 9+/-3 months of follow-up. CONCLUSIONS: On the surface ECG, RMVT from the ASC has a QRS morphology similar to that of RVOT arrhythmias. The indexes of R-wave duration and R/S-wave amplitude can be used to differentiate between the two origins. Radiofrequency ablation can be safely performed within the left ASC with a catheter cannulating the LMCA.

Substrate mapping vs. tachycardia mapping using CARTO in patients with coronary artery disease and ventricular tachycardia: impact on outcome of catheter ablation.

AIMS: For ablation of ventricular tachycardia (VT) in patients after myocardial infarction, a three-dimensional mapping system is often used. We report on our overall success rate of VT ablation using CARTO in 47 patients, with a subgroup analysis comparing VT mapping with the results of mapping that had to be performed during sinus rhythm or pacing (substrate mapping). METHODS AND RESULTS: A CARTO map was performed and VT ablation attempted using two strategies: Patients in the VT-mapping group had incessant VT (four patients) or inducible stable VT (18 patients) such that the circuit of the clinical VT could be reconstructed using CARTO. During VT, the critical area of slow conduction was identified using diastolic potentials and conventional concealed entrainment pacing. In contrast, patients in the substrate-mapping group had initially inducible VT. However, a complete VT map was not possible because of catheter-induced mechanical block (six patients) or because haemodynamics deteriorated during the ongoing VT (19 patients). Therefore, pathological myocardium was identified by fragmented, late- and/or low-amplitude (<1.5 mV) bipolar potentials during sinus rhythm or pacing, and the ablation site was primarily determined by pace mapping inside or at the border of this pathological myocardium. Acute ablation success in all patients with regard to non-inducibility of the clinical VT or any slower VT was 79% after a single ablation procedure, but increased to 95% after a mean of 1.2 ablation procedures. However, chronic success was 75%, when it was defined as freedom from any ventricular tachyarrhythmia (VT or VF) during a follow-up of 25+/-13 months. In the subgroup analysis, patients in the VT-mapping group were not significantly different from patients in the substrate-mapping group with regard to age (65+/-7 vs. 65+/-9 years), ejection fraction (30+/-7 vs. 30+/-8%), VT cycle length (448+/-81 vs. 429+/-82 ms), number of radiofrequency applications (17+/-9 vs. 14+/-6 applications), use of an irrigated tip catheter (23 vs. 32%), and ablation results. CONCLUSION: When using a CARTO-guided approach for VT ablation in patients with coronary artery disease, the freedom from any ventricular arrhythmia is high (75%), but leaves the patient at a 23% risk of developing fast VT/VF during follow-up. Mapping during sinus rhythm or pacing is as successful as mapping during VT.

Focal atrial tachycardia originating from the musculature of the coronary sinus.

Focal atrial tachycardias originate predominantly from the right atrium along the crista terminalis and less commonly from the left atrium. Successful catheter ablation usually can be performed via an endocardial approach. We report the case of a 34-year-old patient in whom a focal atrial tachycardia was successfully ablated 4 cm within the coronary sinus after extensive mapping of the left atrial endocardium and coronary sinus using the three-dimensional CARTO mapping system. Rarely, atrial tachycardia can originate from the coronary sinus musculature and require ablation inside the coronary sinus.

Risk of sudden death after successful accessory atrioventricular pathway ablation in resuscitated patients with Wolff-Parkinson-White syndrome.

INTRODUCTION: Cardiac arrest in patients with Wolff-Parkinson-White (WPW) syndrome can be due to ventricular fibrillation mediated by fast conduction over the accessory pathway during atrial fibrillation. However, if primary ventricular fibrillation is the reason for resuscitation, placement of an implantable cardioverter defibrillator (ICD) would be indicated. The aim of this study was to test the hypothesis that in resuscitated patients with WPW syndrome, recurrences can be prevented by sole ablation of their accessory pathways. METHODS AND RESULTS: We performed a long-term follow-up study of 48 resuscitated patients with WPW syndrome who underwent successful accessory pathway ablation as their sole primary treatment. Cardiac arrest had occurred either spontaneously in 32 patients (group A) or after intravenous administration of antiarrhythmic drugs in 16 patients (group B) and was never associated with an acute myocardial infarction or other concomitant factors. All patients had normal left ventricular function at echocardiography. A total of 56 accessory AV pathways were ablated successfully with radiofrequency current (n = 55) or during surgery (n = 1) and were located at the left free wall (n = 35), right free wall (n = 8), or septal-paraseptal region (n = 13). Follow-up 5.0+/-1.9 years after ablation (range 0.2 to 7.9) was obtained in all 48 patients. All of the patients were alive, and none had a life-threatening arrhythmia or syncope after successful ablation of their accessory pathways. CONCLUSION: In resuscitated patients with WPW syndrome who have normal left ventricular function at echocardiography and no ECG abnormalities suggesting additional electrical disease, ablation of their overt accessory pathways prevented cardiac arrest recurrences; therefore, ICD placement is generally not indicated.