Double Ventricular Response with Aberrant Conduction Leading to Ventricular Dysfunction

Double ventricular response (DVR), where a single P wave results in two QRS complexes, is a rare presentation of dual AV node physiology. It has been associated with ventricular dysfunction in the setting of incessant tachycardia. We present the case of an otherwise healthy adolescent who had frequent DVR without tachycardia leading to left ventricular dysfunction. Slow pathway modification led to a significant reduction in ectopy and normalization of ventricular function. This highlights that DVR without tachycardia might lead to ventricular dysfunction in pediatric patients. Slow pathway modification with reduction of ectopy may be sufficient to restore ventricular function.

Five Criteria Predict Induction and Ablation of Supraventricular Tachycardia

INTRODUCTION

Current guidelines recommend electrophysiological study (EPS) and ablation for primary treatment of supraventricular tachycardia (SVT), but there is little information to guide patient selection for the procedure. The purpose of this study was to identify preoperative features that would predict whether patients with signs or symptoms of tachycardia were likely to have SVT induced and ablated at EPS.

METHODS

We performed a retrospective chart review of 1089 patients referred for EPS and ablation of SVT at 2 high volume centers. The population consisted of a derivation cohort of 810 patients and a validation cohort of 279 patients. We evaluated various clinical, EKG, and monitor features to determine which ones correlated with SVT induction or ablation.

RESULTS

Five preoperative findings predicted a high probability that SVT would be induced and ablated at EPS: 1. A characteristic EKG recording of SVT. 2. Termination of SVT with adenosine. 3. Termination of SVT or symptoms with vagal maneuvers. 4. An episode of SVT lasting ≥ 30 s on a monitor recording. 5. Pre-excitation on the baseline EKG. Patients exhibiting at least one of these features had a high probability of SVT induction and ablation, while those exhibiting none had a low probability (Induction, 76% vs. 19%, RR = 3.96 (2.76-5.69), p < .001; Ablation, 88% versus 26%, RR = 3.32 (2.48-4.46), p < .001). A point-based score was derived and validated that can be used to estimate the probability of induction and ablation for individual patients.

CONCLUSION

Simple criteria classify patients as having a high or low probability of SVT induction and ablation at EPS. They can be used as a guide for clinical decision making when considering invasive testing for patients with symptoms of tachycardia.

Validation of dual atrioventricular nodal physiology in dual atrioventricular nodal non-reentrant tachycardia via adenosine triphosphate injection during atrial pacing: A novel insight into the role of leftward inferior extension

INTRODUCTION

Dual atrioventricular nodal non-reentrant tachycardia (DAVNNT) is a rare and challenging-to-diagnose arrhythmia, without previous reports associating it with a leftward inferior extension (LIE).

METHODS

Diagnosis was made using adenosine triphosphate (ATP) injection during atrial pacing in a suspected DAVNNT patient.

RESULTS

Ablation of the rightward inferior extension was unsuccessful in eliminating DAVNNT; however, subsequent ablation of the LIE successfully eradicated the arrhythmia.

CONCLUSION

This unique case, marked by the first instance of DAVNNT caused by LIE, diagnosed through ATP injection, underscores the utility of this diagnostic approach and broadens the spectrum of our understanding and management of this condition.

Irregular Rhythm in a Middle-Aged Man Presenting With New-Onset Heart Failure

A man in his 50s with recurrent palpitations, fatigue, and progressive exertion dyspnea had irregular narrow-QRS tachycardia in an incessant, repetitive fashion with heart rates up to 180 beats per minute and occasional short runs of wide-QRS tachycardia on Holter monitoring and 12-lead electrocardiogram. What would you do next?

The great deceiver: a case series of 'double fire' atrioventricular nodal response

Background

The 'double fire' (DF) atrioventricular (AV) nodal response is a rare mechanism of two ventricular electrical activations following a single atrial beat due to dual AV node physiology. DF AV nodal response is often misdiagnosed and may lead to unnecessary invasive procedures.

Case summary

We describe a series of three cases with distinct clinical manifestations of DF AV nodal response: Patient 1 remained symptomatic after slow pathway modification for common AV nodal re-entry tachycardia. Patient 2 was misdiagnosed as having junctional bigeminy and developed heart failure with reduced left ventricle ejection fraction. Patient 3 was misdiagnosed as having atrial fibrillation (AF) and underwent two pulmonary vein isolation (PVI) procedures, without clinical improvement. All patients underwent an electrophysiological study (EPS) during which DF AV nodal response was confirmed and treated with radiofrequency ablation of the slow pathway. All patients were afterwards relieved from their symptoms.

Discussion and conclusion

DF AV nodal response is a rare electrophysiological phenomenon which can be clinically misinterpreted as other common arrhythmias, such as premature junctional bigeminy or AF and can contribute to tachycardia induced cardiomyopathy. Typical electrocardiogram- and EPS-derived findings can be indicative for DF AV nodal response. DF AV nodal response can be easily and effectively treated by slow pathway ablation.

Dual atrioventricular nodal non-reentrant tachycardia: Various atrioventricular conduction responses to atrioventricular simultaneous pacing

BACKGROUND

Specific pacing methods to unmask the existence of the dual atrioventricular (AV) nodal pathway in patients with dual AV nodal non-reentrant tachycardia remain to be established.

OBJECTIVE

This study aimed to determine the electrophysiological characteristics of dual AV nodal non-reentrant tachycardia by its responses to specific pacing methods.

METHODS

Five patients diagnosed as having dual AV nodal non-reentrant tachycardia were retrospectively investigated.

RESULTS

Atrial pacing could not induce the clinical tachycardia as continuous double firing in any of the 5 patients, but did induce sudden prolongation of the A-H interval as the linking phenomenon in 1 patient. A single atrial extrastimulation after sinus excitations was performed without interruption of double firing in 1 patient, and it induced the double ventricular response phenomenon within the limited range of the extrastimulus intervals. The pacing method of AV simultaneous basic pacing preceding atrial programmed extrastimulation did not allow interruptions of double firing during the basic drive trains and induced the double ventricular response phenomenon within the limited range of the extrastimulus intervals in all 5 patients, even in 1 patient without inducibility of the clinical tachycardia in the catheterization laboratory. The double ventricular response phenomenon within the limited range of the extrastimulus intervals may be based on the existence of the dual AV nodal pathway with concealed retrograde penetration.

CONCLUSION

The AV simultaneous basic pacing preceding atrial programmed extrastimulation method consistently and reproducibly unmasked the existence of the dual AV nodal pathway as the double ventricular response phenomenon in patients with dual AV nodal non-reentrant tachycardia.

Case report: Dual atrioventricular nodal non-reentrant tachycardia with six types of ECG patterns leading to tachycardia-induced cardiomyopathy in a 51-year-old man

More than three types of ECG manifestations in one patient with dual atrioventricular nodal non-reentrant tachycardia (DAVNNT) are rare. We report a 51-year-old male patient with DAVNNT consisting of six types of ECG patterns leading to tachycardia-induced cardiomyopathy. After radiofrequency ablation of the slow pathway, DAVNNT was eliminated and cardiac function was restored.

Unusual cause of cardiomyopathy in a young woman

Dual atrioventricular nodal nonreentrant tachycardia (DAVNNT) is a rare form of supraventricular tachycardia. In some patients, the presence of a dual pathway physiology results in two paths in the atrioventricular (AV) node with different conduction velocities. An atrial impulse arriving at the AV node may unfold and travel along these two pathways simultaneously, causing two ventricular activations. Thus, the ventricular rate will be twice the atrial rate. DAVNNT is less common than AVNRT, but its frequency may be underestimated.

The ECG is crucial to suspect the diagnosis. At first glance it looks like an irregular tachycardia, but a more careful look shows a rhythmic pattern. A sinus P wave followed by two QRS complexes (narrow or wide) should raise suspicion of this arrhythmia.

It is often unnoticed by the patient, and ventricular dysfunction due to tachycardiomyopathy is not uncommon. The response of DAVNNT to medication, including beta-blockers, flecainide, and amiodarone is very poor or absent, so the treatment of choice is slow pathway ablation. We report a Case of cardiomyopathy caused by this entity.

Frequent inappropriate implantable cardioverter defibrillator therapy was determined to be dual atrioventricular nodal non-reentrant tachycardia: A case report

RATIONALE

Dual atrioventricular node non-reentrant tachycardia (DAVNNRT) is a rare arrhythmia. We present a case of inappropriate implantable cardioverter defibrillator (ICD) therapy caused by DAVNNRT. DAVNNRT is easily misdiagnosed as atrial fibrillation and is often identified as ventricular tachycardia (VT) by the supraventricular tachycardia-ventricular tachycardia (SVT-VT) discriminator of the ICD.

PATIENT CONCERNS

A 73-year-old man with ischemic heart disease (IHD) presented with palpitations accompanied by dyspnea and syncope. Frequent multifocal premature ventricular beats and non-sustained ventricular tachycardia were observed on ambulatory electrocardiography. The left ventricular ejection fraction decreased to 32%.

DIAGNOSIS

He was diagnosed with IHD, heart failure with reduced ejection fraction (HFrEF), and VT.

INTERVENTIONS

: Initially, the patient received a single-chamber ICD implantation for secondary prevention of sudden death. He then suffered from inappropriate anti-tachycardia pacing (ATP)/shock therapy many times after the procedure. DAVNNRT was confirmed in an electrophysiology study (EPS), and radiofrequency ablation of the slow pathway successfully terminated this tachycardia.

OUTCOMES

No episode of inappropriate ICD therapy or tachycardia occurred during the follow-up.

LESSONS

In conclusion, it is essential to have a full understanding of DAVNNRT and eliminate slow pathways for patients with DAVNNRT and be prepared to implant an ICD.

Transesophageal electrophysiology study in the diagnosis of dual atrioventricular nodal nonreentrant tachycardia

“Double fire” is generally characterized by 1:2 atrioventricular conduction of sinus beats traveling down fast and slow pathways that result in double ventricular response. When this phenomenon repeats rapidly, dual atrioventricular nodal nonreentrant tachycardia (DAVNNT) occurs. We report a case of an irregular tachycardia with a comprehensive record that includes an electrocardiogram, a transesophageal electrophysiology study, and an intracardiac electrophysiology study. This is the first report of transesophageal electrophysiology study in the diagnosis of DAVNNT. A diagnosis of DAVNNT was deduced, and the patient was successfully treated with radiofrequency ablation of the slow pathway.

Outcomes in patients with dual antegrade conduction in the atrioventricular node: insights from a multicentre observational study

BACKGROUND

Supraventricular tachycardias induced by dual antegrade conduction via the atrioventricular (AV) node are rare but often misdiagnosed with severe consequences for the affected patients. As long-term follow-up in these patients was not available so far, this study investigates outcomes in patients with dual antegrade conduction in the AV node.

METHODS AND RESULTS

In this multicentre observational study, patients from six European centres were studied. Catheter ablation was performed in 17 patients (52 ± 16 years) with dual antegrade conduction via both AV nodal pathways between 2012 and 2018. Patients with the final diagnosis of a manifest dual AV nodal non-re-entrant tachycardia had a mean delay of the correct diagnosis of over 1 year (range 2-31 months). Two patients received prescription of non-indicated oral anticoagulation, two further patients suffered from inappropriate shocks of an implantable cardioverter defibrillator. In 12 patients, a co-existence of dual antegrade and re-entry conduction in the AV node was present. Mean fast pathway conduction time was 138 ± 61 ms and mean slow pathway conduction time was 593 ± 134 ms. Successful radiofrequency catheter ablation was performed in all patients. Post-procedurally oral anticoagulation was discontinued, without detection of cerebrovascular events or atrial fibrillation during a long-term follow-up of median 17 months (range 6-72 months).

CONCLUSION

This first multicentre study investigating patients with supraventricular tachycardia and dual antegrade conduction in the AV node demonstrates that catheter ablation is safe and effective while long-term patient outcome is good. Autonomic tone dependent changes in ante- vs. retrograde conduction via slow and/or fast pathway can challenge the diagnosis and therapy in some patients.

Successful cryoablation of dual atrioventricular nodal nonreentrant tachycardia: First reported cases

We describe two consecutive adult males with incessant dual atrioventricular nodal nonreentrant tachycardia and associated severe cardiomyopathy. After invasive diagnosis, this is the first published report showing the successful outcome of this rare tachycardia with effective cryoablation. Cryothermal lesions in the roof of the proximal coronary sinus and right midseptal area lead to complete resolution of the tachycardia-mediated cardiomyopathy in the mid-term follow-up of our patients.

Challenges in Narrow QRS Complex Tachycardia Interpretation

Several arrhythmogenic substrates may generate narrow QRS complex tachycardia, frequently encountered in clinical practice. Some narrow QRS complex tachycardias, however, are sustained by an uncommon arrhythmogenic mechanism. Although rare, these forms should be taken into account in the differential diagnosis to avoid misdiagnosis and improper patient management. Dual atrioventricular node physiology can be responsible for different uncommon forms of narrow QRS complex tachycardia, also nonreentrant in mechanism. A ventricular origin also is possible, if the tachycardia site is located in the upper ventricular septum with fast ventricular propagation to the specific conduction system and narrowing of the QRS complex.

The Value of Baseline and Arrhythmic ECG in the Interpretation of Arrhythmic Mechanisms

Owing to the rapid development of new electrophysiologic techniques, our understanding of arrhythmias and their underlying mechanisms has reached unprecedented levels. In some cases, baseline ECG alterations can be identified before arrhythmia development; early recognition of these alterations is of utmost importance to start appropriate preventive therapies and stratify the risk according to patients' outcomes. Hereby, we report a systematic revision of main baseline ECG abnormalities and their implications on clinical outcomes.

[AV nodal reentrant tachycardia. Diagnosis and therapy]

The AV nodal reentrant tachycardia (AVNRT) is one of the most common arrhythmias encountered in clinical practice. It is characterized by a constant heart rate and an on/off phenomenon. The clinical symptoms may include palpitations, anxiety, polyuria, and dyspnea. Typically, tachycardia may be disrupted by vagal maneuvers in many patients. First-line treatment of symptomatic AVNRT is radiofrequency ablation. The present article deals with the characteristics, differential diagnosis and treatment of AVNRT in the EP lab. It is the second part of a series of manuscripts which may facilitate further education in the specific field of electrophysiology.