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Background: This study aimed to establish a systematic method for diagnosing atrioventricular nodal reentrant tachycardia (AVNRT) with a bystander concealed nodoventricular pathway (cNVP). Methods: We analyzed 13 cases of AVNRT with a bystander cNVP, 11 connected to the slow pathway (cNVP‐SP) and two to the fast pathway (cNVP‐FP), along with two cases of cNVP‐related orthodromic reciprocating tachycardia (ORT). Results: The diagnostic process was summarized in three steps. Step 1 was identification of the presence of an accessory pathway by resetting the tachycardia with delay (n = 9) and termination without atrial capture (n = 4) immediately after delivery of a His‐refractory premature ventricular contraction (PVC). Step 2 was exclusion of ORT by atrio‐His block during the tachycardia (n = 4), disappearance of the reset phenomenon after the early PVC (n = 7), or dissociation of His from the tachycardia during ventricular overdrive pacing (n = 1). Moreover, tachycardia reset/termination without the atrial capture (n = 2/2) 1 cycle after the His‐refractory PVC was specifically diagnostic. Exceptionally, the disappearance of the reset phenomenon was also observed in the two cNVP‐ORTs. Step 3 was verification of the AVN as the cNVP insertion site, evidenced by an atrial reset/block preceding the His reset/block in fast–slow AVNRT with a cNVP‐SP and slow–fast AVNRT with a cNVP‐FP or His reset preceding the atrial reset in slow–fast AVNRT with a cNVP‐SP. Conclusion: AVNRT with a bystander cNVP can be diagnosed in the three steps with few exceptions. Notably, tachycardia reset/termination without atrial capture one cycle after delivery of a His‐refractory PVC is specifically diagnostic. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 48-year-old man with a dual atrioventricular nodal physiology that has a narrow QRS tachycardia. Scanning and stimulation showed double ventricular response and a stim-H2 interval with a diagnosis of SVT-2 as a junctional tachycardia (JT). Additional radio frequency (RF) was not applied and the patient has been free from any tachycardia for 32 months.

The article describes the case of a 79-year-old man with ischemic heart disease who underwent catheter ablation of persistent atrial tachycardia (AT). The man received a pulmonary vein isolation, left atrial (LA) posterior wall isolation, and lateral mitral isthmus linear ablation of atrial fibrillation and AT. Also discussed are the earliest activation site in the LA and the need of physicians to pay attention when using AT entertainment pacing in macro-reentrant tachycardias.

The article presents a case study of a 72-year-old man with regular narrow QRS tachycardia after pulmonary vein isolation and cavotricuspid isthmus (CTI) ablation. Topics include accidental ventricular premature depolarization timed to the His‐refractory period not reseting the tachycardia; and tachycardia being induced and terminated by atrial burst pacing and atrial extra‐ stimulation.

The article presents a case of a 72-year-old female who was presented for radiofrequency ablation of narrow QRS tachycardia with ventriculoatrial block (VAB) to discuss the mechanism of VAB in tachychardia. Also cited are the use of atrial extra-stimulation to monitor her dual atrioventricular nodal physiology and VAB during atrioventricular nodal reentrant tachycardia (AVNRT).

The article describes a case of a male patient who was hospitalized due to symptomatic palpitations. Topics mentioned include the mechanism of a narrow QRS tachycardia with different atrial sequence during ventricular pacing, the atrial activation sequences of ventriculoatrial conduction, and the rare existence of atrioventricular nodal reentrant tachycardia with retrograde activation.

Left ventricular (LV) twist can be evaluated using two-dimensional speckle tracking echocardiography (2DSTE) by analyzing difference between apical and basal rotation. However, it is unable to evaluate global rotational dyssynchrony because it cannot assess mid-wall rotation. Recently developed three-dimensional STE (3DSTE) can investigate LV global rotational dyssynchrony. In this study, we investigated the role of torsion on the long-term effects of cardiac resynchronization therapy ( CRT) using 3DSTE. We evaluated 43 patients by 3DSTE: 12 CRT responders, 14 CRT nonresponders, and 17 healthy normal controls. Regional torsion and rotation were assessed using 3DSTE across 16 segments during CRT-off (native conduction) and CRT-on. The following parameters were calculated: global peak twist, Δ global peak twist (difference between CRT-on and CRT-off), and torsion delay index. The torsion delay index was considered to be the rotational energy lost by rotational dyssynchrony. Global peak twist did not show significant differences between the responders and nonresponders during CRT-off (4.0 ± 3.4° vs. 2.8 ± 2.3°, P = 0.295), but it significantly improved in responders compared to nonresponders after CRT-on (5.4 ± 3.5° vs. 2.6 ± 2.6°, P = 0.029). The torsion delay index during CRT-off was significantly higher in responders compared to nonresponders and normal controls (18.5 ± 11.3 vs. 8.6 ± 3.8 and 7.8 ± 5.5, P = 0.010 and P = 0.004, respectively). The torsion delay index during CRT-off significantly correlated with the Δ global peak twist (r = 0.503, P = 0.009). Improvement in LV global peak twist, which is one of the mechanisms for the long-term effects of CRT correlated with the torsion delay index during native conduction that can only be calculated by 3DSTE. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 77-year-old woman with palpitations. An electrocardiogram during the tachycardia showed a narrow complex tachycardia with a long RP supraventricular tachycardia which was diagnosed as atypical atrioventricular nodal reentrant tachycardia (AVNRT) with a concealed nodofascicular (NF) or nodoventricular (NV) bypass tract. Also noted is the condition's termination by a ventricular premature depolarization (VPD).