Inducible Supraventricular Tachycardia Research Articles

Long-Term Follow-Up In Paroxysmal Atrial Fibrillation Patients With Documented Isolated Trigger.

Supraventricular tachycardias may trigger atrial fibrillation (AF). The aim of the study was to evaluate the prevalence of supraventricular tachycardia (SVT) inducibility in patients referred for AF ablation and to evaluate the effects of SVT ablation on AF recurrences. 249 patients (mean age: 54 ± 14 years) referred for paroxysmal AF ablation were studied. In all patients, only AF relapses had been documented in the clinical history. 47 patients (19%; mean age: 42 ± 11 years) had inducible SVT during the electrophysiological study and underwent an ablation targeted only at SVT suppression. Ablation was successful in all 47 patients. The ablative procedures were: 11 slow-pathway ablations for atrioventricular nodal re-entrant tachycardia; 6 concealed accessory pathway ablations for atrioventricular re-entrant tachycardia; 17 focal ectopic atrial tachycardia ablations; 13 with only one arrhythmogenic pulmonary vein. No recurrences of SVT were observed during the follow-up (32 ± 18 months). 4 patients (8.5%) showed recurrence of at least one episode of AF. Patients with inducible SVT had less structural heart disease and were younger than those without inducible SVT. A significant proportion of candidates for AF ablation are inducible for an SVT. SVT ablation showed a preventive effect on AF recurrences. Those patients should be selected for simpler ablation procedures tailored only to the triggering arrhythmia suppression.

A rapid wide complex tachycardia

A rapid wide complex tachycardia

Postnatal recurrence and transesophageal inducibility of prenatally treated fetal supraventricular tachycardia.

Antiarrhythmic treatment of fetal supraventricular tachycardia (SVT) is used to prevent morbidity and mortality. The postnatal management of survivors is often arbitrary and varied. The purpose of this study was to examine the utility of a risk-based postnatal management strategy. Sixty-six prenatally treated newborns with fetal long or short ventriculoatrial tachycardia were reviewed. Postnatal diagnoses included atrioventricular reentrant tachycardia, atrial ectopic tachycardia, and permanent junctional reciprocating tachycardia. Unless SVT persisted to birth, early neonatal observation without treatment was recommended. For newborns without spontaneous arrhythmia after ≥2 days of observation, inducibility was tested by transesophageal pacing study (TEPS). Postnatal therapy was advised for spontaneous or inducible SVT. Characteristics associated with these outcomes were analyzed. Twenty-eight patients (42%) experienced SVT at or early after birth, which was associated with fetal long ventriculoatrial tachycardia (odds ratio [OR] 6.8; 95% confidence interval [CI] 1.88-24.57; P = .0029); delayed in utero cardioversion with treatment (median 11 days vs 5.5 days; P < .0001); prenatal treatment with multiple antiarrhythmics (OR 4.42; 95% CI 1.56-12.55; P = .0059); and postnatal atrial ectopic tachycardia/permanent junctional reciprocating (OR 18.0; 95% CI 2.11-153.9; P = .0013). Of the 38 neonates undergoing TEPS, 19 (50%) had inducible tachyarrhythmias. Recurrence of SVT during infancy or childhood was documented in 4 of 6 patients with SVT at birth (66%), 8 of 22 patients with early neonatal SVT (36%), 4 of 19 patients with inducible SVT (21%), and 0 of 19 untreated patients without inducible SVT (0%) (P= .0032). The postnatal risk of SVT is related to the arrhythmia mechanism and prenatal treatment response. In newborns without spontaneous SVT, TEPS may be useful to guide the need for postnatal treatment on the basis of SVT inducibility.

B-AB13-02 A NOVEL VARIANT IN MANNOSE RECEPTOR C-TYPE 2 IDENTIFIED IN INDIVIDUALS WITH FAMILIAL WOLFF-PARKINSON-WHITE SYNDROME

Wolff-Parkinson-White (WPW) syndrome is the most common arrhythmia disorder observed in patients with structurally normal hearts and affects up to 1% of the population. A common cause of supraventricular tachycardia (SVT) worldwide, WPW contributes to sudden cardiac death in otherwise healthy children and adults. The genetic basis of WPW syndrome remains to be elucidated in individuals with structurally normal hearts. Identify a novel variant causing WPW in the structurally normal heart, leading to further insight into the molecular underpinnings of re-entry bypass tract formation. Whole exome sequencing (WES) was performed on 2 members of a three-generation extended family in which multiple members were affected by SVT, WPW pattern, or WPW syndrome. Shared non-synonymous variants between these 2 family members were then tested in all other family members and demonstrated a variant in the Mannose Receptor C-type 2 (Mrc2) gene. In addition, 154 unrelated individuals with WPW syndrome underwent whole exome sequencing and of these 75 were trio pairs, for a total of 324 subjects. An Mrc2 E990G knock-in mouse model was generated and used for experimental analysis. Resting serial ECGs, electrophysiology studies, echocardiography and optical mapping studies were performed. WES revealed a novel monogenic heterozygous variant E990G in Mrc2 as the disease-causing candidate gene. In Mrc2 E990G knock-in mice, ECGs did not demonstrate a WPW pattern, but a significantly higher incidence of inducible supraventricular tachycardia, in both heterozygous and homozygous mice, was observed with in vivo electrophysiology studies, while echocardiography did not show any change in cardiac structure or function. Furthermore, optical mapping studies also demonstrated an increased burden of SVT, and an abnormal conduction patterns suggesting the presence of a re-entry bypass tract. This study identifies a novel nonsynonymous variant E990G in the gene Mrc2 in familial WPW syndrome. Furthermore, the presence of this variant in a murine model leads to increased incidence of supraventricular tachycardia and bypass tract formation in the setting of preserved cardiac structure and function.

Characteristics of antegrade-only accessory pathways in children and adolescents.

There is minimal data regarding antegrade-only accessory pathways in young patients. Given evolving recommendations and treatments, retrospective analysis of the clinical and electrophysiologic properties of antegrade-only pathways in patients <21 years old was performed, with subsequent comparison of electrophysiology properties to age-matched controls with bidirectional pathways. Of 522 consecutive young patients with ventricular pre-excitation referred for electrophysiology study, 33 (6.3%) had antegrade-only accessory pathways. Indications included palpitations (47%), chest pain (25%), and syncope (22%). The shortest value for either the accessory pathway effective refractory period or the pre-excited R-R interval was taken for each patient, with the median of the antegrade-only group significantly greater than shortest values for the bidirectional group (310 [280-360] ms versus 270 [240-302] ms, p < 0.001). However, the prevalence of pathways with high-risk properties (effective refractory period or shortest pre-excited R-R interval <250 ms) was similar in both study patients and controls (13% versus 21%) (p = 0.55). Sixteen patients had a single antegrade-only accessory pathway and no inducible arrhythmia. Six patients had Mahaim fibres, all right anterolateral with inducible antidromic reciprocating tachycardia. However, 11 patients with antegrade-only accessory pathways and 3 with Mahaim fibres had inducible tachycardia due to a second substrate recognised at electrophysiology study. These included concealed accessory pathways (7), bidirectional accessory pathways (5), and atrioventricular node re-entry (2). Antegrade-only accessory pathways require comprehensive electrophysiology evaluation as confounding factors such as high-risk conduction properties or inducible Supraventricular Tachycardia (SVT) due to a second substrate of tachycardia are often present.

Value of provocative electrophysiology testing in the management of pediatric patients after congenital heart surgery.

To determine the impact of provocative electrophysiology testing in postoperative congenital heart disease (CHD) patients on the management of supraventricular tachycardia (SVT) and clinical outcomes. This is a retrospective study including patients<18 years of age with surgery for CHD who had postoperative SVT between 2006 and 2017. Postoperative outcomes were compared between patients with and without postoperative electrophysiology testing using the Wilcoxon rank sum test, Fisher's exact test, Kaplan-Meier method with the log-rank test, and Cox proportional hazard model. From 341 patients who had SVT after surgery for CHD, 65 (19%) had postoperative electrophysiology testing. There was no significant difference in baseline patient characteristics or surgical complexity between patients with and without electrophysiology testing. Patients with inducible SVT on electrophysiology testing were more likely to have recurrence of SVT prior to hospital discharge with an odds ratio 4.0 (95% confidence interval 1.3, 12.0). Patients who underwent postoperative electrophysiology testing had shorter intensive care unit (12 [6, 20] vs 16 [9, 32] days, HR 2.1 [95% CI 1.6, 2.8], P<.001) and hospital (25 [13, 38] vs 31 [18, 54] days, HR 1.8 [95% CI 1.4, 2.4], P<.001) length of stay. Postoperative electrophysiology testing was associated with improved postoperative outcomes, likely related to the ability to predict recurrence of arrhythmia and tailored antiarrhythmic management.

Comparison of Electrophysiologic Profiles in Pediatric Patients with Incidentally Identified Pre-Excitation Compared with Wolff-Parkinson-White Syndrome

The rising utilization of screening electrocardiograms has resulted in increased incidental identification of ventricular pre-excitation in pediatric patients. We compared accessory pathways of incidentally identified pre-excitation to Wolff-Parkinson-White Syndrome (WPW) with the aim to identify factors important in preprocedural counseling and planning. This single-center, retrospective study of patients ≤18 years without congenital heart disease identified 227 patients diagnosed with pre-excitation and referred for invasive electrophysiology study between 2008 and 2017. WPW Syndrome was diagnosed in 178 patients, while 49 patients had incidental identification of pre-excitation. Anterograde conduction of incidentally identified accessory pathways was not clinically different between the two cohorts at baseline or upon isoproterenol infusion. However, the proportion of accessory pathways meeting high-risk criteria was significantly lower than in patients diagnosed with WPW, 12% versus 28% (p < 0.05). Retrograde conduction at baseline of incidentally diagnosed accessory pathways was slower with a median block cycle length 365 milliseconds (IQR 260 to 450) versus 290 milliseconds (IQR 260 to 330, p < 0.01). In the incidentally identified cohort, right-sided, paraHisian, and fascicular pathways were more common with fewer attempted ablations (71% vs 94%, p < 0.001) and lower success rate (91% vs 97%, p < 0.001). A binomial logistic regression analysis further indicated patients incidentally identified with pre-excitation were associated with having lower rates of inducible supraventricular tachycardia, atrial fibrillation, and ablations performed, in addition, to having right-sided pathways. In conclusion, as patients with incidentally identified pre-excitation present more frequently for consideration of invasive electrophysiology study, these results impact procedural approaches, technical considerations, patient counseling, and outcome expectations.

Influence of advancing age on clinical presentation, treatment efficacy and safety, and long-term outcome of inducible paroxysmal supraventricular tachycardia without pre-excitation syndromes: A cohort study of 1960 patients included over 25 years.

AimTo investigate the influence of increasing age on clinical presentation, treatment and long-term outcome in patients with inducible paroxysmal supraventricular tachycardia (SVT) without pre-excitation syndromes.MethodsClinical and electrophysiological study (EPS) data, as well as long-term clinical outcome (mean follow-up 2.4±4.0 years) were collected in patients referred for regular tachycardia with inducible SVT during EPS without pre-excitation.ResultsAmong 1960 referred patients, 301 patients (15.4%) were aged ≥70 (70–97). In this subset, anticoagulants were prescribed in 49 patients following an erroneous diagnosis of atrial tachycardia and 14 were previously erroneously diagnosed with ventricular tachycardia because of wide QRS. Ablation was performed more frequently in patients ≥70 despite more frequent failure and complications. During follow-up, higher risks of AF, stroke, pacemaker implantation and death were observed in patients ≥70 whereas SVT recurrences were similar in both age groups. In multivariable analysis, age ≥70 was independently associated with higher risks of SVT-related adverse events prior to ablation (OR = 1.93, 1.41–2.62, p<0.001), conduction disturbances (OR = 11.27, 5.89–21.50, p<0.001), history of AF (OR = 2.18, 1.22–3.90, p = 0.009) and erroneous diagnosis at baseline (OR = 9.14, 5.93–14.09, p<0.001) as well as high rates of procedural complications (OR = 2.13, 1.19–3.81, p = 0.01) and ablation failure (OR = 1.68, 1.08–2.62, p = 0.02). In contrast, age ≥70 was not significantly associated with a higher risk of AF in multivariable analysis.ConclusionsA sizeable proportion of patients with inducible SVT without pre-excitation syndromes are elderly. These patients exhibit higher risks of erroneous tachycardia diagnosis prior to EPS as well as failure and/or complication of ablation, but similar risk of SVT recurrence. These results support performing transesophageal EPS in most patients and intracardiac EPS in selected patients. EPS may furthermore prove useful in elderly patients with regular tachycardia, mainly by avoiding treatment based on an erroneous diagnosis.

Adenosine‐sensitive Wolff‐Parkinson‐White: Longer time across the atrioventricular groove

Successful ablation sites in Wolff-Parkinson-White syndrome (WPW) are characterized by short atrioventricular (AV) intervals. Approximately 15% of patients with WPW have adenosine-sensitive accessory pathways (APs). We sought to determine if local AV intervals of adenosine-sensitive APs are different from those of adenosine-insensitive APs in patients with WPW. Patients ≤21 years with WPW and adenosine-sensitive APs who underwent successful ablation over a 9-year period were included. Patients with WPW and adenosine-insensitive APs were matched by age and weight in a 1:2 case-control design. AP location, antegrade and retrograde conduction properties, supraventricular tachycardia (SVT) inducibility, local AV interval, interval from delta wave onset to local ventricular activation (del-V), and time to loss of preexcitation were reviewed. Fourteen patients with adenosine-sensitive APs and 28 with adenosine-insensitive APs were included. Patients with adenosine-sensitive APs had minimum 1:1 antegrade AP conduction at a longer median paced cycle length (380, interquartile range [IQR] 295 to 585ms vs 290, IQR 250 to 330ms, P=0.046), were less likely to have inducible SVT (35.7%vs 75.0%, P=0.035), and had a longer median local AV interval (40.5, IQR 30.8 to 58.3ms vs 32.0, IQR 29.3 to 37.8ms, P=0.029) when compared to those with adenosine-insensitive APs. Patients with WPW and adenosine-sensitive APs have 1:1 antegrade AP conduction at longer cycle lengths, lower likelihood of SVT induction, and longer local AV intervals when compared to those with adenosine-insensitive APs. In patients with WPW, it may be important to consider adenosine response when selecting appropriate ablation targets.

176-30: Performance of the SA-VA difference to differentiate atrioventricular nodal reentrant tachycardia from orthodromic reentrant tachycardia in a large cohort of consecutive patients

Background: The SA-VA difference represents a simple diagnostic maneuver to distinguish between atrioventricular nodal reentrant tachycardia (AVNRT) and orthodromic reentrant tachycardia (ORT) during electrophysiology study. However, its usefulness has largely been studied in selected patient subgroups. Objective: The purpose of this study was to evaluate the performance of the SA-VA difference against commonly used diagnostic maneuvers in a large cohort of consecutive patients. Methods: Consecutive patients with inducible supraventricular tachycardia and successful entrainment through pacing trains from right ventricular apex during an electrophysiological study were included. Atrial tachycardias were excluded. The following intervals were calculated for each patients: SA-VA difference; his potential and atrial electrogram during entrainment minus his potential and atrial electrogram during tachycardia (ΔHA); and the corrected return cycle (cPPI-TCL). Results: A total of 456 patients fulfilled the inclusion criteria, of which electrophysiological study revealed 265 typical AVNRT, 38 atypical AVNRT, 54 and 108 ORT through a septal and free-wall accessory pathway, respectively. An SA-VA difference >99 ms identified AVNRT in all patients with sensitivity, specificity, positive and negative predictive values of 97.7%, 96.9%, 98.3%, and 95.7%, respectively. Conclusions: This study confirms the high ability to distinguish AVNRT from ORT using the SA-VA difference, not only in selected patient subgroups, but as whole when a cutoff of >99 ms is used. Comparison of pacing maneuvers for AVNRT vs. ORT AUC = area under ROC curve (95% CI); NPC = negative predictive value; PPV = positive predictive value. Comparison of pacing maneuvers for AVNRT vs. ORT AUC = area under ROC curve (95% CI); NPC = negative predictive value; PPV = positive predictive value.

Performance of the SA-VA Difference to Differentiate Atrioventricular Nodal Reentrant Tachycardia from Orthodromic Reentrant Tachycardia in a Large Cohort of Consecutive Patients.

The stimulus-atrial (SA) interval minus ventriculoatrial (VA) interval (SA-VA) difference represents a simple diagnostic maneuver to distinguish between atrioventricular nodal reentrant tachycardia (AVNRT) and orthodromic reentrant tachycardia (ORT) during electrophysiology study. However, its usefulness has largely been studied in selected patient subgroups. The purpose of this study was to evaluate the performance of the SA-VA difference against commonly used diagnostic maneuvers in a large cohort of consecutive patients. Consecutive patients with inducible supraventricular tachycardia and successful entrainment through pacing trains from right ventricular apex during an electrophysiological study were included. Atrial tachycardias were excluded. The following intervals were calculated for each patient: SA-VA difference, His potential, and atrial electrogram during entrainment minus His potential and atrial electrogram during tachycardia, and the corrected return cycle. A total of 456 patients fulfilled the inclusion criteria, of which electrophysiological study revealed 265 typical AVNRT, 38 atypical AVNRT, and 54 and 108 ORT through a septal and free-wall accessory pathway, respectively. An SA-VA difference >99 ms identified AVNRT in all patients with sensitivity, specificity, and positive and negative predictive values of 97.7%, 96.9%, 98.3%, and 95.7%, respectively. This study confirms the high ability to distinguish AVNRT from ORT using the SA-VA difference, not only in selected patient subgroups, but as whole when a cut-off of >99 ms is used.

OUTCOMES OF EMPIRIC SLOW PATHWAY ABLATION IN DOCUMENTED BUT NON-INDUCIBLE SUPRAVENTRICULAR TACHYCARDIA

Empiric slow pathway ablation (ESPA) is a slow pathway ablation in patients with non-inducible supraventricular tachycardia (SVT) at electrophysiology study (EPS). We earlier documented that the practice of ESPA is common in Canada (5-10% of SVT cases); evidence to support this approach is limited. The aim of this study is to assess efficacy and safety of ESPA in adults. A multi center cohort study of patients who had ESPA between January 2008 and October 2013 was performed. Patients were identified by screening reports of consequent SVT ablation procedures. Forty-three (5%) out of 859 SVT ablation procedures were identified as ESPA. The median age was 53 (IQR: 24) years, 63% were female; none had structural heart disease. All patients had pre-EPS documentation of SVT (either strip or ECG). In 23 (53.5%) cases, pre-EPS ECG convincingly showed short RP tachycardia. Frequency of pre-procedural episodes ranged between daily to quarterly. During diagnostic EPS, none of the patients had inducible SVT or explicit signs of an accessory pathway. Thirty-two (74.4%) patients had DAVNP plus echo beats, 9 (20.9%) patients had DAVNP only, and 2 (4.7%) patients had no DAVNP. Junctional rhythm (JR) as procedural endpoint was noted in 39 (90.7%) patients. In 18 (41.9%) patients, abolishment of DAVNP was achieved. No complications were encountered. A median follow up of 17 months (6 to 31 months) revealed 83.7% (36 of 43) success rate, defined as absence of pre-procedural symptoms and any documented sustained arrhythmia during follow-up. All recurrences (n=7) occurred within 2 months after the procedure. As compared to patients with recurrence (n=7), patients with no recurrence (n=36) had significantly higher prevalence of clinical short RP tachycardia (61.1% vs. 14.3%, p=0.038), and EPS finding of DAVNP plus echo beats (80.6% vs. 42.9%, p=0.034). Groups were similar with respect to other baseline characteristics. In patients with DAVNP, presence of echo beats on EPS was associated with a higher 2-year probability of freedom from recurrence (90.6% vs. 55.6%, Long-rank P=0.023). Absence of DAVNP plus echo beats on EPS was the only predictor of recurrence in Cox proportional hazards model (p=0.048. HR: 4.53 95%CI 1.013 to 20.23). JR alone versus JR plus abolishment of DAVNP as procedural endpoints had no influence on long-term success (p=0.27). ESPA is a reasonable approach in patients with documented SVT, in particular short RP tachycardia, who are not inducible at EPS. Larger studies are required to assess this practice.

Empirical slow pathway modulation: clinical and procedural characteristics as well as long term follow-up

Introduction: Atrioventricular nodal reentrant tachycardia (ANVRT) is the most common supraventricular tachycardia (SVT). First line treatment is the radiofrequency (RF) modulation of the slow pathway (SPM). For patients with a typical history in whom AVNRT is non inducible, the current guidelines give a Class 2 recommendation for empirical SPM (ESPM) under the precondition that both, dual nodal pathway physiology (DNP) and a surface ECG compatible with AVNRT exist. This recommendation is based on small series of patients. Patient population and outcome: Out of 2927 patients who underwent SPM at our institution between 1994 and 2012, we included 223 patients who clinically suffered from SVT but had no inducible SVT. We here present data on 63 of these patients who received a long term follow-up. Follow up of the remaining 160 patients is under way and will be completed by the end of 2012. 73% of the 63 patients (27 male; 36 female; mean age 51±2 yrs) had an ECG documentation of SVT. Programmed atrial stimulation during electrophysiological study revealed DNP in 91% of patients by occurrence of either an AH jump (n=33) or 1 or 2 echo beats (1 echo beat: n=37; 2 echo beats: n=13). Presence of an accessory pathway was excluded in all cases. In 97% of all patients either ECG documentation existed or DNP was present. ESPM was performed in all patients. No severe complications occurred in any of the patients. A telephone questionnaire was conducted for long term follow up (mean follow up interval 29±3 months). 44% of all patients reported to be free of symptoms. 48% of the patients reported an improvement of symptoms in at least one of the following criteria; duration, intensity or frequency of arrhythmia events. 8% had experienced no improvement. Out of those patients with ECG documentation only, but absence of DNP (n=9), 6 were free of symptoms and 3 reported improvement of symptoms. Out of those patients with DNP but absence of ECG documentation (n=15), 6 reported freedom from symptoms, 8 reported improvement of symptoms and 1 did not benefit at all. Conclusion: Our data show that empiric slow pathway modulation is a safe procedure that improves clinical symptoms in the majority of patients during long term follow up. This also seems to apply for cases where there is no DNP but a characteristic ECG documentation, and vice versa.

Lone Atrial Fibrillation in the Young – Perhaps Not So “Lone”?

To determine if pediatric patients with a history of lone atrial fibrillation (AF) have other forms of supraventricular tachycardia (SVT) that may potentially trigger AF. A multicenter review of patients with lone AF who underwent electrophysiology (EP) study from 2006-2011 was performed. age ≤21 years, normal ventricular function, structurally normal heart, history of AF, and EP study and/or ablation performed. congenital heart disease or cardiomyopathy. Patient demographics, findings at EP study and follow-up data were recorded. Eighteen patients met inclusion criteria. The mean age was 17.9±2.2 years, weight was 82±21 kg, body mass index was 27±6, and 15 (83%) were males. Eleven (61%) were overweight or obese. Seven (39%) had inducible SVT during EP study: 5 atrioventricular nodal re-entry tachycardia (71%) and 2 concealed accessory pathways with inducible atrioventricular re-entry tachycardia (29%). All 7 patients with inducible SVT underwent radiofrequency ablation. There were no complications during EP study and/or ablation for all 18 patients. The mean follow-up was 1.7±1.5 years and there were no recurrences in the 7 patients who underwent ablation. There were 2 recurrences of AF in patients with no other form of SVT during EP study. Inducible SVT was found in 39% of pediatric patients undergoing EP study for lone AF. EP study should be considered for pediatric patients presenting with lone AF.

Approaches to empiric ablation of slow pathway: results from the Canadian EP web survey

Dual atrioventricular nodal physiology (DAVNP) is a frequent finding in patients with suspected or documented supraventricular tachycardia (SVT). Empiric slow pathway ablation (ESPA) is sometimes performed in patients with DAVNP without inducible SVT at the time of electrophysiological study. Evidence to guide this practice in the adult population is limited. This study was aimed to assess the practice of ESPA by adult electrophysiologists in Canada. All Canadian interventional electrophysiologists (n = 81) were invited to complete a web-based questionnaire assessing their practice of ESPA in patients with suspected and documented SVT. Operator experience, reimbursement models, diagnostic, and treatment decisions regarding ESPA were assessed with case scenarios. Forty-one responses (50 %) were obtained. Ninety-five percent of the responders stated that the evidence for ESPA is lacking or limited. Responders were more likely to perform ESPA in the setting of non-inducible SVT when there was documentation of the clinical arrhythmia (64 vs. 31 % (p = 0.017)). The threshold to perform ESPA was highly variable. Longer time in practice (r = 0.38, p = 0.017) and less perceived complications with ESPA (r = 0.31, p = 0.05) were correlated with the practice of ESPA, whereas length of ablation waiting lists (r = -0.15, p = 0.38), number of procedures performed per day (r = 0.11, p = 0.51) and type of reimbursement (p = 0.24) were not associated with the practice of ESPA. The perceived complication rate with ESPA was <1 %. Variability in the practice of ESPA in cases of non-inducible SVT exists. Documentation of the clinical arrhythmia, operator experience, and perceived low complication rates positively influence this practice.

Transesophageal Evaluation of Asymptomatic Wolff‐Parkinson‐White Syndrome

Risk stratification for Wolff-Parkinson-White (WPW) by intracardiac electrophysiology study (ICEPS) carries risks related to catheterization. We describe an alternative approach by using transesophageal electrophysiology study (TEEPS). The pediatric electrophysiology database was reviewed for patients with WPW and no documented clinical supraventricular tachycardia (SVT) who underwent risk stratification by TEEPS from October 2005 to November 2010. Of those who underwent subsequent ICEPS, only those with data available to compare accessory pathway (AP) conduction during ICEPS and TEEPS were included. Of 65 patients who underwent TEEPS, 42 were found to have an indication for ablation. The most common indication for ICEPS was inducible SVT, which was induced in 67% of patients. Of 42 patients who underwent subsequent ICEPS, 23 had sufficient data for comparison of AP conduction between ICEPS and TEEPS. There was no difference between the baseline minimum 1:1 antegrade conduction through the accessory pathway found at TEEPS versus ICEPS (312 ± 51 ms vs 316 ± 66 ms, P = 0.5). There was no significant difference between the baseline antegrade AP-effective refractory period found at TEEPS versus ICEPS (308 ± 34 ms vs 297 ± 37 ms, P = 0.07). There were no complications related to TEEPS or ICEPS. TEEPS is a safe and feasible alternative to ICEPS for risk stratification in patients with asymptomatic WPW and should be considered before ICEPS and ablation.

Remote-Controlled Magnetic Navigation and Ablation With 3D Image Integration as an Alternative Approach in Patients With Intra-Atrial Baffle Anatomy

Improvement in outcome of infants born with congenital heart defects has been accompanied by an increasing frequency of late arrhythmias. Ablation is difficult because of multiple tachycardias in the presence of complex anatomy with limited accessibility. We report on remote-controlled ablation using magnetic navigation in conjunction with 3D image integration in patients with previous intra-atrial baffle procedures. Thirteen patients (8 male; age, 30.5±8 years) with supraventricular tachycardia (SVT) underwent catheter ablation. Group A had a medical history of a Mustard or Senning operation, whereas group B had undergone total cavopulmonary connection. A total of 26 tachycardias were treated in 17 procedures (median cycle length of 280 ms). Group A patients had more inducible SVTs than group B, and all index SVTs were located in the remainder of the morphological right atrium in all but 1 patient. Retrograde access through the aorta was performed and led to successful ablation, using magnetic navigation with a very low total radiation exposure (median of 3.8 minutes in group A versus 5.9 minutes in group B). Only 1 of 13 patients continued to have short-lasting SVTs despite 3 ablation procedures during a median follow-up time of >200 days. Remote-controlled catheter ablation by magnetic navigation in combination with accurate 3D image integration allowed safe and successful elimination of SVTs, using an exclusively retrograde approach, resulting in low radiation exposure for patients after intra-atrial baffle procedures (Mustard, Senning, or total cavopulmonary connection).

Wenckebach During Supraventricular Tachycardia

In case 1, a 71-year-old man with a history of coronary artery disease presented with recurrent paroxysmal supraventricular tachycardia (SVT) despite treatment with β-blockers. During electrophysiology study, the baseline sinus cycle length was 895 ms, atrial-His (AH) interval was 120 ms, and His-ventricular interval was 60 ms. A narrow complex SVT with tachycardia cycle length of 480 ms was initiated with atrial overdrive pacing at 400 ms, as well as with single atrial extrastimuli. The tachycardia showed a long RP interval with regular concentric atrial activation pattern and atrioventricular Wenckebach conduction (Figure 1). Ventricular overdrive pacing during tachycardia repeatedly terminated the tachycardia without activation of the atrium (Figure 2). Figure 1. Inducible SVT with Wenckebach block above the His (arrows) in patient 1 (ECG leads I, III, V1, and V6). His d indicates distal His; His p, proximal His; CS 1,2, distal coronary sinus; CS 7,8, proximal coronary sinus; and RVa, right ventricular apex. Figure 2. Ventricular overdrive pacing terminates tachycardia with ventriculoatrial block (arrow) (ECG leads I, III, V1, and V6 …

How many atrial fibrillation ablation candidates have an underlying supraventricular tachycardia previously unknown? Efficacy of isolated triggering arrhythmia ablation

Supraventricular tachycardia may trigger atrial fibrillation (AF). The aim of the study was to evaluate the prevalence of supraventricular tachycardia (SVT) inducibility in patients referred for AF ablation and to evaluate the effects of SVT ablation on AF recurrences. Two hundred and fifty-seven patients (185 males; mean age: 53.4 ± 14.6 years) referred for AF ablation were studied. In all patients only AF relapses had been documented in the clinical history. Twenty-six patients (10.1%; mean age: 43.4 ± 13.3 years; 17 males) had inducible SVT during electrophysiological study and underwent an ablation targeted only at SVT suppression. Ablation was successful in all 26 patients. The ablative procedures are: 12 slow-pathway ablations for atrioventricular nodal re-entrant tachycardia; 9 concealed accessory pathway ablations for atrioventricular re-entrant tachycardia; and 5 focal ectopic atrial tachycardia ablations. No recurrences of SVT were observed during the follow-up (21 ± 11 months). Two patients (7.7%) showed recurrence of at least one episode of AF. Patients with inducible SVT had less structural heart disease and were younger than those without inducible SVT (interventricular septum thickness: 8.4 ± 1.6 vs. 11.0 ± 1.4 mm, P < 0.01; left atrial diameter: 37.0 ± 3.0 vs. 44.0 ± 2.2 mm, P < 0.01; age: 43.4 ± 13.3 vs. 57.3 ± 11.2 years, P < 0.01). Prevalence of paroxysmal AF was higher in patients with inducible SVT when compared with those with only AF (84.6 vs. 24.6%, P < 0.01). A significant proportion of candidates to AF ablation are inducible for a SVT. SVT ablation showed a preventive effect on AF recurrences. Those patients should be selected for simpler ablation procedures tailored only on the triggering arrhythmia suppression.

182 History of stroke in patients with paroxysmal supraventricular tachycardia. clinical significance

Atrial fibrillation (AF) is a major cause of embolic event, but the significance of other arrhythmias remains unknown. The purpose of study was to assess the significance of unexplained stroke in patients who had apparently only supraventricular tachycardia (SVT). Unexplained stroke was noted in 26 patients (pts) (group I) admitted for palpitations and electrophysiological study (EPS); they were issued from a population of 1002 pts with normal ECG in sinus rhythm, palpitations or tachycardia and with inducible SVT at EPS; 976 pts had no history of stroke (group II). EPS consisted of atrial pacing and programmed atrial stimulation in control state and if necessary after infusion of isoproterenol. Clinical and electrophysiological data of both groups were studied. Pts with stroke had a normal carotid ultrasound study and transcranial Doppler ultrasonography. Pts with unexplained stroke represent 2.5% of population with SVT. They were older than remaining pts without stroke (65±10 vs 50±19 years) (p 0.001). They have more frequently associated heart disease (8/26, 31% vs 37/976, 4%) (p < 0.001). Male gender was more frequent in group I (16/26, 60%) than in group II (355/956, 37%) (p< 0.05). Typical AV node re-entrant tachycardia was noted in 17 group I pts (65%) and 693/976 (68%) (NS); AV re-entrant tachycardia associated with a concealed accessory pathway was noted in 2 group I pts (8%) and 168 group I pts (17%) (NS); atypical AV node re-entrant tachycardia was more frequent in group I (7/26, 27%) than in group II (115/976, 12%) (p<0.05). AF induction was more frequent in group I (6/26, 23%) than in group II (35/976, 3.5%) (p< 0.001). Ablation was performed in 6 group I pts; one of them died from another stroke; another one died suddenly; another one developed a permanent AF. Old age, male gender, associated heart disease, and induction of atrial fibrillation were significant factors associated with the history of stroke in pts with SVT. They have a risk of adverse events during the follow-up. However, unexplained stroke was a rare event in patients with paroxysmal SVT, noted in 2.5% of this population.