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A 72-year-old man was implanted with a biventricular implantable cardioverter defibrillator 6 years ago for ischemic dilated cardiomyopathy with a healed myocardial infarction associated with severe left ventricular systolic dysfunction, complete left bundle-branch block, and New York Heart Association Class II heart failure. Programming a low tachycardia detection rate decreases the incidence of undetected slow VTs but may lead to inappropriate detection and treatment of supraventricular tachycardia, more commonly sinus tachycardia. References 1 Bänsch D, Castrucci M, Böcker D, Breithardt G, Block M. Ventricular tachycardias above the initially programmed tachycardia detection interval in patients with implantable cardioverter-defibrillators: incidence, prediction and significance. [Extracted from the article]

A 59-year-old man with no history of cardiovascular disease was admitted to the emergency department with sudden onset of rapid palpitations and dizziness 2 hours before admission. ECG (Figure 1) revealed a rapid irregular wide QRS complex tachycardia with right bundle-branch block morphology and alternating QRS width. Twelve-lead ECG once sinus rhythm was restored after electrical cardioversion. [Extracted from the article]

A 14‐year‐old girl with a history of recurrent palpitations and documented wide QRS complex tachycardia was referred for electrophysiologic study and catheter ablation. [ABSTRACT FROM AUTHOR]

The article focuses on the differential diagnosis of a regular wide QRS complex tachycardia with left bundle branch block (LBBB) like morphology and 1:1 AV relationship. Topics discussed include ascertaining whether the tachycardia mechanism is antidromic tachycardia or supraventricular tachycardia with bystander accessory pathway, chart of twelve-lead electrocardiogram and intracardiac tracings, and fusion of ventricular activation between antegrade conduction.

Atrial Tachycardia Incidence After RF versus Cryoballoon PVI Background Postablation atrial tachycardia (AT) is a significant complication following radiofrequency (RF) pulmonary vein isolation (PVI). Cryoballoon (CB) ablation is an alternative technique for PVI that appears to have a low incidence of AT. No direct comparison between AT risk in RF and CB ablation has been made. Objective To compare the incidence and characteristics of ATs after PVI with RF and with CB ablation in patients with paroxysmal atrial fibrillation (AF). Methods All patients who underwent their first PVI between January 2006 and September 2012 using either RF or CB ablation were included. When a repeat ablation procedure for AT was performed, the arrhythmia was classified as typical cavotricuspid isthmus (CTI) flutter or left atrial tachycardia (LA-AT) based on invasive mapping procedure findings and ECG P-wave morphology. Results The study population consisted of 415 and 215 consecutive patients in the RF and CB groups, respectively. After a mean follow-up of 38 ± 21 months, 52 (8.3%) patients presented ATs (9.4% and 6% in the RF and CB groups, respectively; P = 0.15). Of those, 26 (4.1%) were classified as LA-AT with 20 (4.8%) in the RF group and 6 (2.8%) in the CB group (P = 0.23). In patients without a history of typical CTI flutter or CTI line (n = 458), the incidence for this type of arrhythmia during follow-up was 3.5%. Conclusion In patients with paroxysmal AF undergoing either RF or CB PVI as the sole ablation strategy, the incidence of postprocedural AT was low and there was no significant difference between the 2 techniques. [ABSTRACT FROM AUTHOR]

VA Intervals to Distinguish PSVT. Introduction: Usefulness of the interval between the last pacing stimulus and the last entrained atrial electrogram (SA) minus the tachycardia ventriculoatrial (VA) interval in the differential diagnosis of supraventricular tachycardias with long (>100 ms) VA intervals has not been prospectively studied in a large series of patients. Our objective was to assess the usefulness of the difference SA-VA in diagnosing the mechanism of those tachycardias in patients without preexcitation. The results were compared with those obtained using the corrected return cycle (postpacing interval-tachycardia cycle length-atrioventricular [AV] nodal delay). Methods and Results: We included 314 consecutive patients with inducible sustained supraventricular tachycardias with VA intervals >100 ms undergoing an electrophysiologic study. Atrial tachycardias were excluded. Tachycardia entrainment was attempted through pacing trains from right ventricular apex. The SA-VA difference and the corrected return cycle were calculated for every patient. Electrophysiologic study revealed 82 atypical AV nodal reentrant tachycardias (AVNRT) and 237 AV reentrant tachycardias (AVRT) using septal (n = 91) or free-wall (n = 146) accessory pathways (APs). A SA-VA difference >110 ms identified an atypical AVNRT with sensitivity, specificity, positive and negative predictive values of 99%, 98%, 95%, and 99.5%, respectively. Similarly, these values were 88%, 83%, 77%, and 92% for SA-VA difference <50 ms in identifying AVRT through a septal versus free-wall AP. The SA-VA difference showed higher accuracy in septal AP identification than that obtained using the corrected return cycle. Conclusion: The difference SA-VA provides a simpler electrophysiologic maneuver that reliably differentiates atypical AVNRT from AVRT regardless of concealed AP location. (J Cardiovasc Electrophysiol, Vol. 22, pp. 915-921, August 2011) [ABSTRACT FROM AUTHOR]

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The article presents a case of a 14-year-old female with documented wide QRS complex tachycardia with left bundle branch block morphology who was referred for catheter ablation and electrophysiologic study. During the study, observation included alternation of sinus rhythm with regular wide QRS complexes with left bundle branch morphology and precordial lead transition. Also identified is a single posterolateral right atriofascicular accessory pathway (Mahaim-type accessory pathway).

The article presents a case study of a 62-year-old woman suffering from regular palpitations that had sudden onset and termination. It states that the presence of anterograde dual-atrioventricular modal physiology was not established during programmed atrial stimulation. It comments on the role a transient acceleration of the sinus rate during tachycardia had in observed changes and confirmed the diagnosis of typical slow-fast atrioventricular nodal reentrant tachycardia.

The article presents a case study of an 88 year old man with no known history of structural heart disease who was admitted to the emergency department complaining of regular palpitations. A discussion of diagnostic testing which was conducted on the man, and resulted in him receiving a diagnosis of a regular wide QRS complex tachycardia, is presented.

The article presents a case study of a 30-year-old woman with a history of exercise-induced paroxysmal heart palpitations. Electrophysiological testing showed irregular tachycardia which was determined to be suggestive of atrial fibrillation. Catheter ablation was performed with a positive clinical outcome.

A 39-year-old female patient was referred for ablation of recurrent episodes of atrioventricular nodal reentrant tachycardia. A combination of an anomalous inferior vena cava with azygos continuation and a persistent left superior vena cava was discovered. A nonfluoroscopic navigation system was very useful for catheter ablation of the tachycardia in this unusual case of anomalous venous system of the heart. [ABSTRACT FROM AUTHOR]

Abstract: We report a case of a patient with recurrent episodes of supraventricular tachycardia in which a concealed left-posterior accessory pathway-mediated orthodromic tachycardia was reproducibly induced during the EP study. Two interesting and very unusual electrophysiological phenomenon were observed at the same time during the ablation procedure of the accessory pathway: 1— Automaticity of the regular accessory atrioventricular pathway; 2— Emergence of manifest preexcitation following radiofrequency application exclusively during the automatic accessory pathway-mediated rhythm. [Copyright &y& Elsevier]

Abstract: The present case report illustrates an atypical electrocardiographic presentation of typical atrioventricular nodal re-entrant tachycardia. Persistent 2:1 AV block during tachycardia is evident and an spontaneous ventricular premature beat during tachycardia resulted in 1:1 AV conduction. [Copyright &y& Elsevier]