Common Types of Supraventricular Tachycardia: Diagnosis and Management.

Supraventricular tachycardia (SVT) is an abnormal rapid cardiac rhythm that involves atrial or atrioventricular node tissue from the His bundle or above. Paroxysmal SVT, a subset of supraventricular dysrhythmias, has three common types: atrioventricular nodal reentrant tachycardia, atrioventricular reentrant tachycardia, and atrial tachycardia. Presenting symptoms may include altered consciousness, chest pressure or discomfort, dyspnea, fatigue, lightheadedness, or palpitations. Diagnostic evaluation may be performed in the outpatient setting and includes a comprehensive history and physical examination, electrocardiography, and laboratory workup. Extended cardiac monitoring with a Holter monitor or event recorder may be needed to confirm the diagnosis. Acute management of paroxysmal SVT is similar across the various types and is best completed in the emergency department or hospital setting. In patients who are hemodynamically unstable, synchronized cardioversion is first-line management. In those who are hemodynamically stable, vagal maneuvers are first-line management, followed by stepwise medication management if ineffective. Beta blockers and/or calcium channel blockers may be used acutely or for long-term suppressive therapy. When evaluating patients for paroxysmal SVTs, clinicians should have a low threshold for referral to a cardiologist for electrophysiologic study and appropriate intervention such as ablation. Clinicians should use a patient-centered approach when formulating a long-term management plan for atrioventricular nodal reentrant tachycardia. Catheter ablation has a high success rate and is recommended as the first-line method for long-term management of recurrent, symptomatic paroxysmal SVT, including Wolff-Parkinson-White syndrome.

Assessment of atrial functional remodeling in patients with atrioventricular nodal reentrant tachycardia with and without drug-induced type 1 Brugada pattern: A case-control study.

PURPOSE: The time interval between the onset of the P-wave on electrocardiogram (ECG) and peak A' velocity of the lateral left atrial wall assessed by tissue Doppler imaging (PA-TDI interval) determine total atrial conduction time (TACT) which reflects atrial remodeling and arrhythmic substrate. In this retrospective study, we aimed to assess TACT in patients with atrioventricular nodal reentrant tachycardia (AVNRT) with and without drug-induced type 1 Brugada electrocardiogram ECG pattern (DI-Type 1 BrP) and control subjects. METHODS: Study population consisted of 62 consecutive patients (46 women; mean age 44 ± 12 years) undergoing electrophysiological study and ablation for symptomatic, drug-resistant AVNRT, and 42 age-matched and sex-matched control subjects. All patients and control subjects underwent ajmaline challenge test and tissue Doppler imaging. RESULTS: A DI-Type 1 BrP was uncovered in 24 of 62 patients with AVNRT (38.7%). PA-TDI interval was similar among AVNRT patients with and without DI-Type 1 BrP (124 ± 12 ms vs 119 ± 14 ms, respectively, P = .32), but significantly longer in patients with AVNRT with as well as without DI-Type 1 BrP than in control subjects (124 ± 12 ms and 119 ± 14 ms vs 105 ± 11 ms, respectively, P < .001). CONCLUSION: The TACT assessed by PA-TDI interval is longer in patients with AVNRT with and without DI-Type 1 BrP than in age-matched and sex-matched healthy control subjects.

Quality of life assessment in children before and after a successful ablation for supraventricular tachycardia.

BACKGROUND AND OBJECTIVES: Young patients suffering from rhythm disorders have a negative impact in their quality of life. In recent years, ablation has become the first-line therapy for supraventricular arrhythmias in children. In the light of the current expertise and advancement in the field, we decided to evaluate the quality of life in young patients with supraventricular arrhythmias before and after a percutaneous ablation procedure. METHODS: The prospective cohort consisted of patients <18 years with structurally normal hearts and non-pre-excited supraventricular arrhythmias, who had an ablation in our centre from 2013 to 2018. The cohort was evaluated with the PedsQL™ 4.0 Generic Core Scales self-questionnaire prior to and post-ablation. RESULTS: The final cohort included 88 patients consisted of 52 males (59%), with a mean age at ablation of 12.5 ± 3.3 years. Forty-two patients (48%) had a retrograde-only accessory pathway mediating the tachycardia, 38 (43%) had atrio-ventricular nodal re-entrant tachycardia, 7 (8%) had ectopic atrial tachycardia, and 1 (1%) had atrial flutter. The main reason for an ablation was the patient's choice in 53%. There were no severe complications. Comparison between the baseline and post-ablation assessments showed that patients reported significant improvement in the scores for physical health, emotional and social functioning, as well as in the total scores. CONCLUSIONS: The present study demonstrates that the successful treatment of supraventricular arrhythmias by means of an ablation results in a significant improvement in the quality of self-reported life scores in young patients.

Atypical Slow-Slow Atrioventricular Nodal Reentrant Tachycardia with Use of a Superior Slow Pathway.

We report a case of atypical slow-slow atrioventricular nodal reentrant tachycardia (AVNRT) utilizing a superior slow pathway as a retrograde limb. The standard electrophysiological criteria confirm the diagnosis of this AVNRT by successfully excluding a diagnosis of atrial tachycardia and atrioventricular reentrant tachycardia. The earliest atrial activation during tachycardia was found at the interatrial septum 17.5 mm superior to the site identified during retrograde conduction with the fast pathway. The tachycardia was not inducible after ablation at the right posterior septum, consistent with successful ablation of the typical slow pathway.

Supraventricular arrhythmia with discordant electrocardiographic features: What is the arrhythmia mechanism?

Junctional and AV nodal reentrant tachycardia share common electrocardiographic features, but they differ in their management and outcomes after catheter ablation. This case concerns a 60-year-old female who presented with recurrent episodes of a relatively slow, regular supraventricular arrhythmia. Electrocardiographic features of the arrhythmia were discordant regarding its underlying mechanism. However, careful analysis of 12-lead electrocardiograms, with focus on the effect of spontaneous premature beats, pointed out the arrhythmia etiology. Electrophysiological study and pacing maneuvers defined the arrhythmic substrate that was successfully treated by catheter ablation.

Atrioventricular nodal reentrant tachycardia and cannon A waves.

Regular, narrow complex tachycardia with a ventricular rate around 150 can be challenging. The differential includes sinus tachycardia, atrioventricular nodal reentrant tachycardia (AVNRT), atrioventricular reentrant tachycardia (AVRT), and atrial tachycardia (focal or macro re-entrant - i.e. flutter). We present a case of a 90-year-old woman presenting with shortness of breath in which the ECG was not diagnostic, but the presence of regular neck pulsations helped secure the diagnosis of AVNRT. In AVNRT, atria and ventricular contractions occur nearly simultaneously. When the right atrium attempts to contract against a closed tricuspid valve, an abrupt increase in venous pressure is encountered. This increase in venous pressure manifests as prominent neck pulsations termed "cannon A waves." The patient was ultimately successfully electrically cardioverted resulting in resolution of her presenting symptoms, neck pulsations, and tachycardia. While irregular "cannon A waves" can be seen in conditions of AV dissociation, regular "cannon A waves" strongly favor the diagnosis of AVNRT.

Multiple Shifts of the Earliest Retrograde Atrial Activation Site Along the Tricuspid Annulus During the Fast-Slow Form of Atrioventricular Nodal Reentrant Tachycardia by Radiofrequency Modification.

A 70-year-old woman was admitted for treatment of supraventricular tachycardia. Ventriculoatrial conduction was revealed through programmed ventricular stimulation; the coronary sinus ostium (CSos) was the earliest atrial activation site. The fast-slow forms of atrioventricular nodal reentrant tachycardia (AVNRT) were induced by ventricular extra-stimuli. During tachycardia, the earliest atrial activation site was located at the bottom of CSos. Radiofrequency (RF) energy application to this site resulted in the delay of local electrical potential, prolongation of tachycardia cycle length, and a shift of the earliest retrograde activation site to the roof of CSos. Subsequent ablation induced a similar shift to the inferior tricuspid annulus and to the right posterior septum. Finally, RF energy application to the right posterior septum resulted in the termination of tachycardia, which was not induced afterward. Multiple shifts in the earliest retrograde atrial activation site along the tricuspid annulus after each slow pathway ablation suggested that annular tissue plays a substantial role as a substrate for AVNRT.

Atypical Fast-Slow Atrioventricular Nodal Reentrant Tachycardia Using a Slow Pathway Extending to the Superoanterior Right Atrium.

We report a case of atypical fast-slow atrioventricular nodal reentrant tachycardia (AVNRT) using a slow pathway variant extending to the superoanterior right atrium. The AVNRT diagnosis was confirmed by using standard electrophysiological criteria that exclude a diagnosis of atrial tachycardia and atrioventricular reentrant tachycardia. The earliest atrial activation during tachycardia was found in the superoanterior right atrium adjacent to the tricuspid annulus, where the first delivery of radiofrequency energy terminated and eliminated the inducibility of the tachycardia.

The athlete's heart is a proarrhythmic heart, and what that means for clinical decision making.

Recurring questions when dealing with arrhythmias in athletes are about the cause of the arrhythmia and, more importantly, about the eligibility of the athlete to continue sports activities. In essence, the relation between sports and arrhythmias can be understood along three lines: sports as arrhythmia trigger on top of an underlying problem, sports as arrhythmic substrate promotor, or sports as substrate inducer. Often, there is no sharp divider line between these entities. The athlete's heart, a heart that adapts so magically to cope with the demands of exercise, harbours many structural and functional changes that by themselves predispose to arrhythmia development, at the atrial, nodal and ventricular levels. In essence, the athlete's heart is a proarrhythmic heart. This review describes the changes in the athlete's heart that are related to arrhythmic expression and focuses on what this concept means for clinical decision making. The concept of the athlete's heart as a proarrhythmic heart creates a framework for evaluation and counselling of athletes, yet also highlights the difficulty in predicting the magnitude of associated risk. The management uncertainties are discussed for specific conditions like extreme bradycardic remodelling, atrioventricular nodal reentrant tachycardia, atrial fibrillation and flutter, and ventricular arrhythmias.

Wide QRS complex supraventricular tachycardia with negative precordial concordance: Electrocardiographic clues for Mahaim pathway with Ebstein anomaly.

Ebstein's anomaly is often accompanied by either Wolff-Parkinson-White syndrome or atriofascicular Mahaim. These bypass tracts give rise to antidromic atrioventricular (AV) re-entrant tachycardias, in which the bypass tract serves as the anterograde limb of the circuit and the AV node as the retrograde limb of the reentrant circuit. Since the antidromic AV reentrant tachycardia over a Mahaim fibre has a typically left bundle braunch block (LBBB) morphology, it is easy to make a misdiagnosis of supraventricular tachycardia with functional LBBB or even of ventricular tachycardia particularly in the presence of negative concordance. Some electrocardiographic clues might prevent misdiagnosis of ventricular tachycardia and inadvertent ICD implantation.

Alternative Treatment Options for Atrioventricular-Nodal-Reentry Tachycardia: An Emergency Medicine Review.

BACKGROUND: Atrioventricular-nodal-reentry tachycardia (AVNRT) is a form of supraventricular tachycardia (SVT) that is relatively common in the emergency department (ED). It is rarely indicative of underlying electrical or structural pathology. OBJECTIVE: This review evaluates the literature and controversies concerning treatment of AVNRT in the ED. DISCUSSION: For treatment of narrow-complex tachycardia, Advanced Cardiovascular Life Support guidelines recommend the use of vagal maneuvers, followed by adenosine. Recent literature suggests that nondihydropyridine calcium channel blockers, such as verapamil and diltiazem, may be as effective as adenosine, without the negative short-term side effects. Multiple studies have demonstrated that although adenosine is rapid acting, there is no statistically significant difference in conversion rate between adenosine and calcium channel blockers. Both medications result in a conversion rate above 90%, but there are significantly more minor adverse effects, such as flushing or chest discomfort, with adenosine. Calcium channel blockers are a viable option for treatment for AVNRT, especially in refractory states. Beta-blockers have been evaluated but should not be used routinely due to lower efficacy. AVNRT is the most common tachydysrhythmia in pregnancy, and vagal maneuvers and adenosine are first line. Electrical cardioversion should be utilized for hemodynamically unstable patients. Most patients with AVNRT may be discharged with appropriate follow-up. CONCLUSION: Several studies demonstrate that nondihydropyridine calcium channels (verapamil and diltiazem) are equally as efficacious as adenosine in converting AVNRT to sinus rhythm, without the negative (albeit short-lived) side effects. If given over 20 min, the risk for hypotension is low.

[Value of transesophageal atrial pacing in neonates with tachyarrhythmia].

OBJECTIVE: To study the value of transesophageal atrial pacing (TEAP) in neonates with tachyarrhythmia. METHODS: The clinical data of 26 neonates with tachyarrhythmia who underwent TEAP electrophysiological examination or cardioversion were collected. RESULTS: Of the 26 neonates, 15(58%) were diagnosed with atrioventricular reentrant tachycardia, 3(12%) were diagnosed with sinus tachycardia, 3(12%) were diagnosed with ventricular tachycardia, 2(8%) were diagnosed with fast/slow atrioventricular nodal reentrant tachycardia, 2(8%) were diagnosed with atrial tachycardia, and 1(4%) was diagnosed with sinus tachycardia with ventricular preexcitation. Overdrive suppression was performed for 22 neonates, among whom 18 achieved successful cardioversion, and 2 with atrial tachycardia and 2 with ventricular tachycardia failed to restore sinus rhythm. CONCLUSIONS: TEAP is helpful to the diagnosis of tachyarrhythmia in neonates and can bring about a high rate of cardioversion success.

Catheter ablation vs. antiarrhythmic drug therapy in patients with symptomatic atrioventricular nodal re-entrant tachycardia: a randomized, controlled trial.

AIMS: To conduct a randomized trial in order to guide the optimum therapy of symptomatic atrioventricular nodal re-entrant tachycardia (AVNRT). METHODS AND RESULTS: Patients with at least one symptomatic episode of tachycardia per month and an electrophysiologic diagnosis of AVNRT were randomly assigned to catheter ablation or chronic antiarrhythmic drug (AAD) therapy with bisoprolol (5 mg od) and/or diltiazem (120-300 mg od). All patients were properly educated to treat subsequent tachycardia episodes with autonomic manoeuvres or a 'pill in the pocket' approach. The primary endpoint of the study was hospital admission for persistent tachycardia cardioversion, during a follow-up period of 5 years. Sixty-one patients were included in the study. In the ablation group, 1 patient was lost to follow-up, and 29 were free of arrhythmia or conduction disturbances at a 5-year follow-up. In the AAD group, three patients were lost to follow-up. Of the remainder, 10 patients (35.7%) continued with initial therapy, 11 patients (39.2%) remained on diltiazem alone, and 7 patients (25%) interrupted their therapy within the first 3 months following randomization, and subsequently developed an episode requiring cardioversion. During a follow-up of 5 years, 21 patients in the AAD group required hospital admission for cardioversion. Survival free from the study endpoint was significantly higher in the ablation group compared with the AAD group (log-rank test, P < 0.001). CONCLUSIONS: Catheter ablation is the therapy of choice for symptomatic AVNRT. Antiarrhythmic drug therapy is ineffective and not well tolerated.

Number of Beats in the Transition Zone With Fixed SA Interval during Right Ventricular Overdrive Pacing Determines Accessory Pathway Location in Orthodromic Reentrant Tachycardia.

BACKGROUND: Ventricular overdrive pacing (VOP) produces reset during the transition zone (TZ) of QRS fusion in orthodromic reentrant tachycardia (ORT) and after the TZ in atrioventricular nodal reentrant tachycardia (AVNRT), and this represents a simple diagnostic maneuver to differentiate the two tachycardia mechanisms. OBJECTIVE: The purpose of this study was to determine whether the number of beats with reset in the TZ predicts accessory pathway (AP) location in ORT. METHODS: We retrospectively reviewed 57 patients with ORT (21 left-sided AP, 20 septal AP, and 16 right-sided AP) and 20 patients with AVNRT (19 typical AVNRT and one atypical AVNRT) who underwent VOP from the right ventricular apex. We analyzed the number of beats with reset during or after the TZ, demonstrated by fixed ventricular stimulus-atrial (SA) interval during VOP. RESULTS: The overall mean tachycardia cycle length [CL] minus VOP CL was 22.6 ± 7.5 ms with no statistical difference between the groups (P = 0.480). The mean number of beats in the TZ with fixed SA interval was 2.5 ± 1.4 for the whole ORT group, 1.1 ± 0.4 for left-sided AP (range 1-2), 2.8  ±  0.9 for septal AP (range 1-5), and 4.0 ± 0.9 for right-sided AP (range 3-6) (P < 0.001). Using a cutoff >2 beats distinguished right- versus left-sided AP in all cases. CONCLUSION: Assessing the number of beats in the TZ with fixed SA interval during VOP helps to determine AP location in ORT and adds valuable information to an established simple diagnostic pacing maneuver, especially when a two-catheter simplified approach is employed.

Overdrive pacing from downstream sites on multielectrode catheters to rapidly detect fusion and to diagnose macroreentrant atrial arrhythmias.

BACKGROUND: Entrainment criteria for macroreentrant arrhythmias are based on detecting fusion between tachycardia and paced wavefronts, but this is often difficult for atrial tachycardias (AT) after ablation of atrial fibrillation. METHODS AND RESULTS: With the use of a multipolar catheter, pacing was performed from electrodes within the coronary sinus showing activation later than adjacent electrodes (downstream overdrive pacing) during 66 ATs in 62 patients: 20 cavotricuspid isthmus-dependent ATs, 20 perimitral ATs, 13 focal ATs with sequential coronary sinus activation, and 13 other macroreentrant left atrial ATs. The paced cycle length was 10 to 30 milliseconds below the tachycardia cycle length (TCL), and activation at the neighboring upstream electrodes was assessed. Downstream overdrive pacing at 48 sites close to a macroreentrant circuit (PPI-TCL <40 milliseconds, where PPI is postpacing interval) produced constant fusion demonstrated by a long stimulus to upstream atrial electrogram interval (S-Au) >75% TCL and was consistent with orthodromic activation of the upstream site despite its close proximity to the pacing site. In contrast, downstream overdrive pacing at 18 sites during focal AT or remote from the macroreentrant AT circuit (PPI-TCL >40 milliseconds) always demonstrated a comparatively short S-Au <25% of TCL (12±4% versus 89±4% of TCL; P<0.001), consistent with direct activation. CONCLUSIONS: Selection of a downstream activation site for overdrive pacing can facilitate rapid recognition of macroreentry and proximity to the reentry circuit using a single multielectrode catheter by recognizing a PPI-TCL <40 milliseconds and S-Au >75% of TCL. Recognition of intracardiac constant fusion with this method is a novel criterion for transient entrainment.

Atypical atrioventricular nodal reentry tachycardia in a child with polyvalvular dysplasia.

A 10-year-old boy with polyvalvular dysplasia and severe involvement of both atrioventricular valves presented with palpitations. Concern was raised for atrial tachyarrhythmia due to biatrial enlargement; however, ambulatory monitoring discovered a reentrant mechanism. Electrophysiology study revealed atypical atrioventricular nodal reentrant tachycardia involving two components of the slow pathway, with inputs in the posterior septum around his dysplastic tricuspid valve. He underwent successful modification of the slow pathway using cryoablation.

Cardiac resynchronisation therapy in patients with atrioventricular nodal disease and reduced ejection fraction - can we afford it?

BACKGROUND: Recent pacing guidelines from the European Society of Cardiology recommend cardiac resynchronisation therapy (CRT) in patients with an atrioventricular (AV) nodal pacing indication and reduced ejection fraction (EF). However, concerns over added expenditure may limit its widespread implementation. We investigate the potential incremental cost of biventricular over right ventricular pacing if such a practice was adopted. METHODS: Retrospective analysis was performed of devices implanted over eight years. The database was analysed for device type, pacing indication and EF. Cost analysis was performed. RESULTS: 1751 devices were implanted over eight years at an averaged cost of AUD$1,369,125 per year. 172 with CRT were excluded. 25.4 (11.6%) patients per year had an EF≤50% and AV nodal disease. 18.4 were in sinus rhythm (SR) and 7.0 in atrial fibrillation (AF). Of these, 13.5 (6.2%) had EF≤45% (9.9 SR, 3.6 AF) and 8.2 (3.8%) had EF≤35% (5.6 SR, 2.6 AF). Based on an incremental cost of $4,000 per device, if all patients with EF≤50% received CRT, the total cost increment per year equates to $73,500 for SR patients or $101,500 if AF patients were included. In patients with EF≤35% and EF≤45%, this amounts to $22,500 and $39,500 per year for SR patients respectively or $33,000 and $54,000 per year if AF patients were included. Depending on the EF and rhythm, this represents a 1.6% to 7.4% increase per year in the pacing budget for an increased patient population of between 2.6% (EF≤35% in SR) to 11.6% (EF≤50%). CONCLUSION: A small proportion of additional patients will qualify for CRT based on the chosen cut-off and rhythm. Although the individual incremental cost for biventricular over right ventricular pacing is high in patients with AV nodal disease and reduced EF, overall this represents at most, a modest increase in the total pacing budget.

Electroanatomically estimated length of slow pathway in atrioventricular nodal reentrant tachycardia.

The length of the slow pathway (SP-L) in atrioventricular (AV) nodal reentrant tachycardia (NRT) has never been measured clinically. We studied the relationship among (a) SP-L, i.e., the distance between the most proximal His bundle (H) recording and the most posterior site of radiofrequency (RF) delivery associated with a junctional rhythm, (b) the length of Koch's triangle (Koch-L), (c) the conduction time over the slow pathway (SP-T), measured by the AH interval during AVNRT at baseline, and (d) the distance between H and the site of successful ablation (SucABL-L) in 26 women and 20 men (mean age 64.6 ± 11.6 years), using a stepwise approach and an electroanatomic mapping system (EAMS). SP-L (15.0 ± 5.8 mm) was correlated with Koch-L (18.6 ± 5.6 mm; R 2 = 0.1665, P < 0.005), SP-T (415 ± 100 ms; R 2 = 0.3425, P = 0.036), and SucABL-L (11.6 ± 4.7 mm; R 2 = 0.5243, P < 0.0001). The site of successful ablation was located within 10 mm of the posterior end of the SP in 38 patients (82.6 %). EAMS-guided RF ablation, using a stepwise approach, revealed individual variations in SP-L related to the size of Koch's triangle and AH interval during AVNRT. Since the site of successful ablation was also correlated with SP-L and was usually located near the posterior end of the SP, ablating anteriorly, away from the posterior end, is not a prerequisite for the success of ablation procedures.

Successful ablation of atypical atrioventricular nodal reentrant tachycardia from a noncoronary sinus of Valsalva.

An 81-year-old man with long RP narrow QRS tachycardia underwent catheter ablation. Ventricular pacing reset the atrial cycle over a retrograde slow pathway, followed by termination of the tachycardia without atrial capture, confirming the diagnosis of fast-slow atrioventricular nodal reentrant tachycardia (AVNRT). The earliest atrial activation during tachycardia was found in the noncoronary sinus of Valsalva, where the first delivery of radiofrequency energy terminated and eliminated the inducibility of the tachycardia, by retrograde conduction block over the slow pathway. This is the first report of a fast-slow AVNRT, with successful ablation of the slow pathway from a noncoronary sinus of Valsalva.