Atrioventricular Tachycardia Research Articles

Utility of the aVL Lead in the Electrocardiographic Diagnosis of Atrioventricular Nodal Re-Entrant Tachycardia

Background: Reciprocating atrioventricular tachycardia can be categorized into common slow–fast atrioventricular node re-entrant (AVNRT) and orthodromic atrioventricular reciprocating tachycardia (AVRT). The electrocardiogram (ECG) during tachycardia is useful in distinguishing these two mechanisms. The presence of a pseudo- R0-wave in lead V1 or pseudo-S-wave in the inferior leads has been widely used, although the value of an isolated aVL lead has not been evaluated yet. To determine whether an isolated aVL lead of the surface 12-lead ECG is useful for the differential diagnosis between AVNRT and AVRT. Methods: This cross sectional observational study was conducted at the department of Cardiology, National Institute of Cardiovascular Diseases & Hospital, for 1-year period. Patient admitted in NICVD due to supraventricular tachycardia and was screened as a case of AVNRT & AVRT were approached for inclusion of the study. After initial management all patients were subjected to perform electrophysiological study and radiofrequency ablation. The specific pattern of changes in aVL lead were recorded in each cases and were analyze to determine the sensitivity, specificity and positive predictive values to estimate AVRT & AVNRT. Informed written consent was taken from the subject and ethical issues were ensured. Total 60 patients were included for final analysis. Data analysis was done by statistical program Statistical Package for Social Science (SPSS) version 20.0. Results: Among the 60 study population, mean age was 41.28±11.21 SD (years) [age range: 18-65 years]. Total 44 patients (73%) had AVNRT and 16 patients (27%) had found AVRT in Electrophysiological evaluation. About 61.7% patients were female and 38.3% patients were male in this study with no significant gender difference in between AVNRT and AVRT group (p>0.05). Total 43.3% patients had aVL notch on ECG. Among patients who had AVNRT, 54.5% had aVL notch and among patients who had AVRT, 12.5% had aVL .........

Orthodromic Atrioventricular Tachycardia in Wolff-Parkinson-White Syndrome with Two Accessory Pathways Participation during the Same AVT

Case report of a 49-year-old patient with Wolff-Parkinson-White syndrome, very symptomatic, with apparent parahisian pathway who, during an electrophysiological study, presented orthodromic atrioventricular tachycardia, featuring two accessory pathways, retrogradely, the parahisian pathway and a hidden left posterolateral pathway, during the same tachycardia, alternating the retrograde pathway of tachycardia without interruption.

Tachycardia and Anxiety in a 14-year-old Boy

Tachycardia and Anxiety in a 14-year-old Boy

Myocardial and Arrhythmic Spectrum of Neuromuscular Disorders in Children.

Neuromuscular disorders (NMDs) are highly heterogenous from both an etiological and clinical point of view. Their signs and symptoms are often multisystemic, with frequent cardiac involvement. In fact, childhood onset forms can predispose a person to various progressive cardiac abnormalities including cardiomyopathies (CMPs), valvulopathies, atrioventricular conduction defects (AVCD), supraventricular tachycardia (SVT) and ventricular arrhythmias (VA). In this review, we selected and described five specific NMDs: Friedreich’s Ataxia (FRDA), congenital and childhood forms of Myotonic Dystrophy type 1 (DM1), Kearns Sayre Syndrome (KSS), Ryanodine receptor type 1-related myopathies (RYR1-RM) and Laminopathies. These changes are widely investigated in adults but less researched in children. We focused on these specific topics due their relative frequency and their potential unexpected cardiac manifestations in children. Moreover these conditions present different inheritance patterns and mechanisms of action. We decided not to discuss Duchenne and Becker muscular dystrophies due to extensive work regarding the cardiac aspects in children. For each described NMD, we focused on the possible cardiac manifestations such as different types of CMPs (dilated-DCM, hypertrophic-HCM, restrictive-RCM or left ventricular non compaction-LVNC), structural heart abnormalities (including valvulopathies), and progressive heart rhythm changes (AVCD, SVT, VA). We describe the current management strategies for these conditions. We underline the importance, especially for children, of a serial multidisciplinary personalized approach and the need for periodic surveillance by a dedicated heart team. This is largely due to the fact that in children, the diagnosis of certain NMDs might be overlooked and the cardiac aspect can provide signs of their presence even prior to overt neurological diagnosis.

Association of high serum soluble interleukin 2 receptor levels with risk of adverse events in patients with cardiac sarcoidosis

Abstract Background Sarcoidosis is a systemic granulomatous disease that affects multiple organs. Among these, the presence of cardiac involvement is recognised as a determinant of worse clinical outcomes. Soluble interleukin 2 receptor (sIL-2R) is a potentially useful biomarker in the diagnosis and evaluation of disease severity in patients with sarcoidosis. However, it remains to be seen whether sIL-2R is associated with the severity and activity of disease in patients with cardiac sarcoidosis (CS). Purpose The aims of this study were to investigate whether sIL-2R was associated with clinical outcomes and to clarify the relationship between sIL-2R levels and disease activity evaluated by 18F-fluorideoxyglucose in positron emission tomography/computed tomography (18F-FDG PET/CT) in patients with CS. Methods We examined 101 consecutive patients with CS who were admitted to our University HospitalbetweenMay 2003 and February 2020. Patients who had no data of serum sIL-2R levels before initiation of immunosuppressive therapy (n=18) were excluded. Ultimately, 83 patients were examined in this study. The primary outcome was a composite of advanced atrioventricular block (AVB), ventricular tachycardia or ventricular fibrillation (VT/VF), heart failure hospitalisation, and all-cause death. Inflammatory activity in the myocardium and lymph nodes were assessed by18F-FDG PET/CT. We used a published program to analyse the cardiac metabolic activity (CMA), and total lymph node glycolysis (TLyG), which are quantitative measures of FDG volume-intensity. Results During a median follow-up period of 2.96 (interquartile range 2.24–4.27) years, the primary outcome occurred in 24 patients (29%), including 1 advanced AVB, 13 VT/VF, 5 hospitalisations for heart failure, and 5 all-cause deaths. Kaplan-Meier analyses showed that the primary outcome occurred more frequently in patients with higher sIL-2R levels (>538 U/mL, the median) than in those with lower sIL-2R levels (Figure). A multivariable Cox regression analysis revealed that a higher sIL-2R level was independently associated with an increased subsequent risk of adverse events (hazard ratio 3.71, 95% confidence interval 1.63–8.44, p=0.002), even after adjustments for age, plasma B-type natriuretic peptide, estimated glomerular filtration rate, left ventricular ejection fraction, and late gadolinium enhancement, which are known to be strong determinants of worse clinical outcomes in patients with CS (Table). Furthermore, sIL-2R levels were significantly correlated with TLyG, the inflammatory activity in lymph nodes (r=0.346, p=0.003) but not with CMA, the inflammatory activity in myocardium (r=0.131, p=0.27). Conclusions Increased sIL-2R is associated with worse long-term clinical outcomes accompanied by increased systemic inflammatory activity in CS patients. These findings suggest the importance of assessing sIL-2R as a surrogate marker for further risk stratification in these patients. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): Japan Society for the Promotion of Science

Remote magnetic navigation shows superior long-term outcomes in pediatric atrioventricular (nodal) tachycardia ablation compared to manual radiofrequency and cryoablation.

BackgroundCatheter ablation (CA) is the first-choice treatment for tachyarrhythmia in children. Currently available CA techniques differ in mechanism of catheter navigation and energy sources. There are no large studies comparing long-term outcomes between available CA techniques in a pediatric population with atrioventricular reentry tachycardia (AVRT) or atrioventricular nodal reentry tachycardia (AVNRT) mechanisms.ObjectiveThis study aimed to compare procedural and long-term outcomes of remote magnetic navigation-guided radiofrequency (RF) ablation (RMN), manual-guided RF ablation (MAN) and manual-guided cryoablation (CRYO).MethodsThis single-center, retrospective study included all first consecutive CA procedures for AVRT or AVNRT performed in children without structural heart disease from 2008 to 2019. Three study groups were defined by the ablation technique used: RMN, MAN or CRYO. Primary outcome was long-term recurrence of tachyarrhythmia.ResultsIn total, we included 223 patients, aged 14 (IQR 12–16) years; weighting 56 (IQR 47–65) kilograms. In total, 108 procedures were performed using RMN, 76 using MAN and 39 using CRYO. RMN had significantly lower recurrence rates compared to MAN and CRYO at mean follow-up of 5.5 ± 2.9 years (AVRT: 4.3% versus 15.6% versus 54.5%, P < 0.001; AVNRT: 7.7% versus 8.3% versus 35.7%, P = 0.008; for RMN versus MAN versus CRYO respectively). In AVNRT ablation, RMN had significantly lower fluoroscopy doses compared to CRYO [30 (IQR 20–41) versus 45 (IQR 29–65) mGy, P = 0.040).ConclusionIn pediatric patients without structural heart disease who underwent their first AV(N)RT ablation, RMN has superior long-term outcomes compared to MAN and CRYO, in addition to favorable fluoroscopy doses.

Remote magnetic navigation shows superior long-term outcomes in pediatric atrioventricular (nodal) tachycardia ablation compared to manual radiofrequency and cryoablation

Abstract Funding Acknowledgements Type of funding sources: None. Introduction – Catheter ablation (CA) is a first-choice treatment for tachyarrhythmia in pediatric patients. The currently available CA techniques differ in manner of catheter steering technique and energy sources. There are no large studies comparing long-term outcomes between the available CA techniques in pediatric patients with atrioventricular reentry (also known as accessory pathway mediated) tachycardia (AVRT) or atrioventricular nodal reentry tachycardia (AVNRT) mechanisms. Objective – The aim of this study was to compare procedural parameters and outcomes of remote magnetic navigation-guided radiofrequency (RF) ablation (RMN), manual-guided RF ablation (MAN) and manual-guided cryoablation (CRYO). Methods – This single-center, retrospective study included all first consecutive CA procedures for AVRT or AVNRT mechanisms performed in pediatric patients with no structural heart disease from January 2008 until June 2019. Three study groups were defined by the ablation technique used: RMN, MAN or CRYO. Primary outcome was recurrence of tachyarrhythmia and/or pre-excitation on ECG. Baseline clinical parameters, procedure times and complication rates were also evaluated. Results – In total, we included 223 patients, aged 13.8 ± 2.8 years, with a mean weight of 55.6 ± 14 kilograms. In total, 108 procedures were performed using RMN, 76 using MAN and 39 using Cryo. RMN had the lowest recurrence rates at a mean follow-up of 5.5 ± 2.9 years (AVRT ablation: 4% vs. 16% vs. 55%, P &amp;lt; 0.001; AVNRT ablation: 8% vs. 8% vs. 36%, P = 0.008; for RMN vs. MAN vs. CRYO respectively). In AVRT ablation, procedure and fluor times were comparable between groups. However, in AVNRT ablation, RMN and MAN had significantly lower fluoroscopy times compared to Cryo (10 (IQR 7-14) vs. 9 (IQR 6-26) vs. 15 (IQR 10-22) minutes respectively, P = 0.040). Moreover, procedure times were shortest in MAN and second in RMN ablation (101 (IQR 87-121) vs. 88 (IQR 62-99) vs. 120 (IQR 88-143) minutes respectively, P = 0.018). We observed minor complications in 3 patients (1%), which were comparable between groups and no major complications. Conclusion – In pediatric patients with no structural heart disease who underwent their first AV(N)RT ablation, RMN has the most favorable long-term outcomes, in addition to favorable fluoroscopy and procedure times. Abstract Figure. AVRT and AVNRT ablation recurrence rates

Antiarrhythmic drugs-safety and efficacy during pregnancy.

When deciding on antiarrhythmic drug (AAD) treatment, athorough knowledge of the physiological adaptation processes that occur during pregnancy and their effect on metabolism and the efficacy of AAD is mandatory. Beyond the desired effects of AAD therapy, side effects can occur in pregnant women. Furthermore, potential harm to fetal development-depending on gestational age-needs to be considered. Athorough evaluation of potential risks opposed to expected benefits for mother and fetus should be carried out before initiation of AAD treatment. Regular maternal echocardiography and fetal sonographic examination during pregnancy under AAD treatment are advisable. If possible, serum concentrations of AAD should be measured on aregular basis. Due to electrolyte and volume imbalances after delivery, maternal monitoring is recommended for approximately 48 h under AAD therapy. Current guidelines are based on almost historic analyses, where AAD were often prescribed for other indications than rhythm disorders. In clinical practice, AAD predominantly used during pregnancy are intravenous adenosine for acute treatment of atrioventricular nodal dependent tachycardias, whereas betablockers, sotalol, and flecainide can be orally administered for long-term therapy.

Long-term prognostic significance of dispersion of ventricular repolarization in patients with cardiac sarcoidosis

Abstract Background Although the presence of cardiac involvement is recognised as a determinant of worse clinical outcomes in sarcoidosis patients, the determinants of adverse outcomes in patients with cardiac sarcoidosis (CS) have not been well understood. T-peak to T-end interval (TpTe) on the surface electrocardiogram (ECG) was proposed as a marker of dispersion of ventricular repolarisation. Prolonged TpTe to QT interval ratio (TpTe/QT) represents a period of potential vulnerability to reentrant ventricular arrhythmias. Notably, prolonged TpTe/QT has been associated with increased risk of mortality in hypertrophic cardiomyopathy, congenital long-QT syndrome, and Brugada syndrome. However, its prognostic implication in patients with CS is unclear. Purpose We sought to investigate whether TpTe/QT was associated with long-term clinical outcomes in patients with CS. Methods A total of 108 consecutive CS patients between August 1986 and March 2019 in two academic hospitals who had ECG data before initiation of immunosuppressive therapy were examined. We excluded patients who received pacemaker (n=15) or cardiac resynchronization therapy (n=3) at the time of ECG. Ultimately, 90 CS patients were included in this study. All standard 12-lead ECGs were recorded at 25 mm/s with an amplification of 10 mm/mV. TpTe was measured from the peak of T wave to the end of T wave which defined as the intersection of the tangent to the down slope of the T wave and the isoelectric line. Lead V5 was selected for the analyses. If V5 is not suitable for analyses, V4 was selected. The primary outcome was the composite of advanced atrioventricular block (AVB), ventricular tachycardia or ventricular fibrillation (VT/VF), heart failure hospitalisation and all-cause death. Results During a median follow-up period of 4.70 (interquartile range [IQR] 2.06–7.23) years, adverse events occurred in 21 patients (23.3%), including 2 advanced AVB, 12 VT/VF, 4 heart failure hospitalisation and 3 all-cause death. Events group had higher TpTe/QT compared to no events group (0.231 [IQR 0.193–0.261] vs. 0.282 [IQR 0.263–0.304] P&amp;lt;0.001). Kaplan-Meier analyses revealed that the primary outcome, especially VT/VF or sudden cardiac death more frequently occurred in patients with higher TpTe/QT (≥0.242, the median) compared to those with lower TpTe/QT (Figure 1). Multivariable Cox regression analysis showed that higher TpTe/QT was independently associated with increased subsequent risk of adverse events (hazard ratio 1.09, 95% confidence interval [CI] 1.02–1.17, P=0.014) even after adjustment for age, sex and left ventricular ejection fraction. Furthermore, the optimal cut-off value of TpTe/QT for the discriminatory of primary outcome was 0.257, and c-index was 0.77 (95% CI 0.64–0.89). Conclusions Higher TpTe/QT was associated with worse long-term clinical outcomes in patients with CS. Our findings indicate the importance of assessing TpTe/QT for risk stratification in patients with CS. Figure 1 Funding Acknowledgement Type of funding source: None

Catheter ablation of common atrioventricular nodal reentry tachycardia using the conventional method

Background and objective: Atrioventricular nodal reentry tachycardia is the commonest type of supraventricular tachycardia referred to the electrophysiology laboratory. It constitutes about two thirds of the supraventricular tachycardia admitted to the emergency department. The mechanism of this tachycardia is reentry. This study aimed to evaluate the efficacy of radiofrequency ablation therapy in atrioventricular nodal reentry tachycardia as the first line treatment using the conventional method. Methods: The standard technique for the electrophysiological study done to induce tachycardia. Three or four catheters were used. Atrial or ventricular programmed stimulation used to induce the tachycardia. Differentiation of the atrioventricular nodal reentry from atrial tachycardia and atrioventricular tachycardia done by ventricular entrainment. The dry ablation catheter of 4 mm tip used to modify the slow pathway. The appearance of junctional rhythm was a sign of the effective application of the radiofrequency application. The success of ablation was indicated by a failure to induce the tachycardia with repeated programmed stimulation. Results: Seventy patients with atrioventricular nodal reentry tachycardia were selected from total supraventricular tachycardia cases of 106 patients referred to the catheter lab for radiofrequency ablation. In 85% of the cases atrial programmed stimulation were used to induce the tachycardia and ventricular programmed stimulation and in 15% of the cases. Acute success rate was seen in 68 patients (97%). Conclusion: Catheter radiofrequency ablation is becoming technically easy, safe, and reliable as first line treatment in the majority of patients with atrioventricular reentry tachycardia.

Clinical observation of paroxysmal atrioventricular reciprocal tachycardia in intermittent Wolff–Parkinson–White syndrome

Aim. To present potentials of electrocardiographic (ECG) research method in the diagnosis of paroxysmal tachycardia, as well as in the presence of additional conduction pathways (DPP). To demonstrate potentials of a trivial method for identification of the type of arrhythmia, the mechanism of occurrence, and topics of the additional conduction pathway in Wolf-Parkinson-White syndrome on a clinical example.&#x0D; Conclusion. A widely available routine method of the ECG allows to determine the nature of arrhythmia, to choose the treatment tactics, to assess the prognosis of the disease, prior to performing complex invasive procedures.

P5361Pregnancy in patients with cardiac arrhythmias

Abstract Introduction Negative trends in the state of somatic and reproductive health of the female population are observed in the last decades all over the world. On the background of declining birth rates, the problems of managing pregnancy in women with extragenital pathology become relevant. Aim To study the effects of cardiac arrhythmias and antiarrhythmic treatment on the course and outcomes of pregnancy. Material and methods A total of 55 case histories of pregnant women hospitalized in the Department of Interventional Arrhythmology. All patients signed informed consent to be enrolled in the study. The age of patients ranged from 17 to 41 years (mean age of 30.2±4.0 years). Patients were hospitalized on average at 28.0±6.4 weeks of gestation (from 12 to 37 weeks) and had some form of cardiac arrhythmia. Results Cardiac arrhythmias were idiopathic in 65% of cases; the rest of patients had verified cardiovascular diseases. Cardiac arrhythmias were registered in 41 (74%) of women prior to pregnancy and their arrhythmological history lasted for 7.9±1.1 years. Extrasystolic arrhythmia was the most common type of cardiac arrhythmias: ventricular premature beats occurred in 23 pregnant women (42%) including supraventricular premature beats in 8 patients (14%), supraventricular tachycardia in 12 patients (22%), and ventricular tachycardia (VT) in 5 women (9%). In three cases, VTs were hemodynamically significant. Radiofrequency ablation (RFA) of VT was performed in pregnant women at 26, 27, and 32 weeks of gestation. Five patients with gestational ages of 27–34 weeks received RFA for atrial tachycardia and atrioventricular (AV) reciprocal tachycardia to treat symptomatic intracardiac tachycardia (n=4) and continuous recurrent AV nodal tachycardia (n=1), paroxysms of which were accompanied by destabilization of hemodynamics. AV block was registered in 4 pregnant women (9%); sick sinus syndrome was diagnosed in 1 patient (2%). Implantation of pacemaker was required in 1 case for a second-degree AV block type II (Mobitz type II) at 24 weeks of pregnancy. RFA and pacemaker implantation were carried out with minimal or zero fluoroscopy and only after the 22nd week of pregnancy, that is, without or with reduced radiation risk to the fetus. 16 patients (29%) had cesarean section; the rest of patients had spontaneous vaginal delivery. The average Apgar scores were 8.64 immediately after birth and 9.35 five minutes after birth. Preterm births (n=2) were due to obstetric pathology and were not associated with cardiac arrhythmias. Cardiac arrhythmias were not observed in any patient in childbirth. Conclusions Cardiac arrhythmias, observed in patients, did not require termination of pregnancy. Catheter ablation for symptomatic, hemodynamically significant, and life-threatening cardiac arrhythmias made it possible to effectively guide pregnant women to delivery with a close follow-up.

When and howdoes a single ventricular premature beat initiate and terminate supraventricular tachycardia?

The differential diagnosis of a supraventricular tachycardia (SVT) is accomplished using a number of pacing maneuvers. The incidence and mechanism of a single ventricular premature beat (VPB) on initiation and termination of tachycardia were evaluated during programmed electrical stimulation (PES) of the heart in patients with the two most common regular SVTs: atrioventricular re-entrant tachycardia (AVNRT) and orthodromic atrioventricular tachycardia (AVRT). Three hundred and thirty-seven consecutive patients aged above 18years with an inducible sustained AVNRT or AVRT were prospectively enrolled. Patients with more than one tachyarrhythmia mechanism were excluded. Two hundred and seventeen patients (64.4%) had typical slow/fast AVNRT and 120 (35.6%) had an orthodromic AVRT using a rapidly conducting accessory pathway for V-A conduction. In this cross-sectional study, we specifically report the analysis of tachycardia induction and termination by a single VPB. Tachycardia induction with a single VPB during sinus rhythm was seen in 7 of 120 AVRT and in only one of the 217 patients with AVNRT, (5.8% vs. 0.3%, p<0.05). When a single VPB was delivered during basic ventricular pacing these values were 28% versus 4%, respectively, (p<0.001). Termination of tachycardia by a single VPB was observed in nine (4.1%) patients with AVNRT and in 57 (47.5%) with AVRT (p<0.001). Initiation of SVT by a single VPB during sinus rhythm was uncommon and favored AVRT. Termination of SVT by a single VPB was commonly seen in AVRT but rarely in AVNRT. These findings can be of help when interpreting a noninvasive arrhythmia event recording.

Abstract 21385: Presenting Features in Suspected Cardiac Sarcoid

Background: Sarcoidosis is multi-system disease characterized by non-caseating granulomas, often presenting with pulmonary involvement. However, in the United States at least one-fourth of sarcoid patients have cardiovascular involvement. Sarcoid can also present as isolated cardiac sarcoidosis (CS), with symptoms that include heart failure (HF), advanced atrioventricular (AV) nodal block, ventricular tachycardia (VT), or sudden cardiac death. Consequently, it has been suggested that CS should be considered in patients presenting with high grade AV block, VT, or heart failure, with a non-ischemic presentation. Here, we present the CS experience at a tertiary medical center. Methods: Patients who underwent 18 F-FDG (2-deoxy-2-[fluorine-18]fluoro-D-glucose) PET/CT to assess perfusion and inflammation for clinical suspicion of CS between 2009-2015 at a tertiary referral center were included in the study. These patients were retrospectively assessed for frequency of presenting features. Results: Inclusion criteria were met by 71 patients. VT was the most common presenting symptom seen in 40 of 71 patients (56%). High grade AV block was seen in 24 of 71 patients (34%). VT and high grade AV block was seen concomitantly in 9 (13%). An abnormal PET result was seen in 51 out of 71 patients (72%) with 30 of 51 having VT (59%) and 21 of 51 having AV block (41%). Of the patients with both VT and AV block, 8 of 9 had abnormal PET studies. In 34 of 71 (47%) patients with known extracardiac sarcoid, 18 (53%) had VT and 11 (32%) had AV block. HF symptoms (New York Heart Association class II-IV) were seen in 24 (34%). An abnormal resting ECG was seen in 64 out of 71 patients (90%). Conclusions: In our retrospective cohort VT is the most common presenting symptom in patients with suspicion of CS, and the combination of AV block with VT should raise concerns for an infiltrative process. In patients with extracardiac sarcoid and rhythm disturbance, cardiac involvement should be suspected and screened. Early identification of cardiovascular involvement is critical to ensure that appropriate management of the source of rhythm disturbance or heart failure is addressed before cardiovascular dysfunction is sustained.

ELECTROPHYSIOLOGICAL EFFECTS OF VALSALVA MANOEUVER DURING EARLY PREGNANCY IN PATIENTS WITH PAROXYSMS OF ORTHODROMIC ATRIOVENTRICULAR TACHYCARDIA

Objective: The aim is to study electrophysiological (EPh) indicators of the heart in pregnant women in the first trimester with orthodrome paroxysms of reciprocal atrioventricular tachycardia during the Valsalva test, after a single dose of propafenone and a combination of Valsalva test with propafenone.Methods: Clinical survey, assessment of medical history, physical examination, electrocardiogram (ECG) in 12 leads, Holter ECG monitoring, echocardiography, expert ultrasound examination of the fetus, transesophageal EPh study of the heart, the blood test for electrolytes (potassium, sodium), thyroid hormones (T3, T4, thyroid-stimulating hormone) were included in this study. We examined 28 women during an early gestation.Results: We found that the Valsalva manoeuver, Propanorm, and the combination of the Valsalva manoeuver and Propanorm produced an antiarrhythmic effect through the anterograde and retrograde conduction in reentry.Discussion: The study is the first to reveal that the Valsalva manoeuver influences retrograde conduction in reentry in pregnant patients.Conclusion: We proved that it is necessary to use the Valsalva manoeuver to stop paroxysms of orthodromic atrioventricular tachycardia (POAVRT) in the first trimester of pregnancy. If the manoeuver is ineffective, it is advisable to use Propanorm or combination of Propanorm with Valsalva manoeuver.

Spectrum of Cardiac Arrhythmias in Isolated Ventricular Non-Compaction.

A wide spectrum of cardiac arrhythmias has been observed in patients with isolated ventricular non-compaction, which is defined by hypertrabeculated ventricular myocardium with deep intertrabecular recesses, in the absence of concomitant congenital heart disease. In this genetically diverse phenotype, the development of fibrosis contributes to an arrhythmogenic substrate underlying atrioventricular conduction diseases, supraventricular tachycardias and ventricular tachycardias. Within this spectrum, monomorphic ventricular tachycardia is the most frequently observed arrhythmia, and this prevalence has important implications for sudden cardiac death risk.

How to Approach Difficult Cases of AVNRT.

Our approach to the ablation of atrioventricular nodal reciprocating tachycardia (AVNRT), the most common supraventricular tachycardia, is as follows: We first attempt ablation in the right atrial posteroseptum anterior to the coronary sinus ostium with a 4-mm non-irrigated tip catheter. If ablation within the triangle of Koch is unsuccessful with radiofrequency (RF), we switch to cryoablation and target a more superior (mid septal) region. We also utilize cryoablation if RF ablation produces transient VA block (absence of retrograde conduction during junctional rhythm) or a fast junctional rhythm (<350msec). If cryoablation were to fail, or is not available, we would then suggest ablation within the coronary sinus targeting the roof (2-4cm from the os) using a 3.5-mm irrigated tip catheter. If tachycardia were still inducible despite these measures, we would then proceed with transseptal puncture (given our greater experience with this over a retrograde aortic approach) and perform RF ablation along the posteroseptal left atrium and inferoseptal mitral annulus utilizing an irrigated tip catheter. In our experience, cryoablation reliably results in elimination of the slow pathway. The only left atrial ablation for AVNRT at our institution in the past year was performed because a patent foramen ovale allowed for rapid left atrial access, facilitating left atrial ablation of the slow pathway.

A 2:1 Atrioventricular Tachycardia Recorded by an Implantable Cardioverter Defibrillator: What Is the Mechanism?

A 2:1 Atrioventricular Tachycardia Recorded by an Implantable Cardioverter Defibrillator: What Is the Mechanism?

Cardiac involvement in hereditary myopathy with early respiratory failure

Objective:To assess whether hereditary myopathy with early respiratory failure (HMERF) due to the c.951434T>C; (p.Cys31712Arg) TTN missense mutation also includes a cardiac phenotype.Method:Clinical cohort study of our HMERF cohort using ECG, 2D echocardiogram, and cross-sectional cardiac imaging with MRI or CT.Results:We studied 22 participants with the c.951434T>C; (p.Cys31712Arg) TTN missense mutation. Three were deceased. Cardiac conduction abnormalities were identified in 7/22 (32%): sustained atrioventricular tachycardia (n = 2), atrial fibrillation (n = 2), nonsustained atrial tachycardia (n = 1), premature supraventricular complexes (n = 1), and unexplained sinus bradycardia (n = 1). In addition, 4/22 (18%) had imaging evidence of otherwise unexplained cardiomyopathy. These findings are supported by histopathologic correlation suggestive of myocardial cytoskeletal remodeling.Conclusions:Coexisting cardiac and skeletal muscle involvement is not uncommon in patients with HMERF arising due to the c.951434T>C; (p.Cys31712Arg) TTN mutation. All patients with pathogenic or putative pathogenic TTN mutations should be offered periodic cardiac surveillance.

Pitfalls of Atrial Advancement Using a Ventricular Extra-stimulus During Supraventricular Tachycardia

The delivery of single His-refractory ventricular extra-stimulus during supraventricular tachycardia is useful to identify the mechanism of the tachycardia. We present the different responses based on the ventricular extra-stimulus site. Our findings demonstrate that the atrial activation via an accessory pathway was not advanced based on the ventricular pacing site. Therefore, atrioventricular tachycardia could masquerade as atrioventricular nodal reentrant tachycardia.