Mitral isthmus block (MIB) complicating radiofrequency ablation (RFA) of orthodromic reciprocating tachycardia (ORT) using left - sided accessory pathways (APs) is poorly understood. Two cases and a systematic review of the literature of patients (pts) who developed MIB complicating left - sided ORT RFA is presented. Among 27 pts (34 ± 12 years old, 54

We describe a rare case of upper septal fascicular ventricular tachycardia (VT) associated with takotsubo syndrome that failed to convert with synchronized shock but converted to normal sinus rhythm after intravenous adenosine administration. The excess catecholamine state of takotsubo syndrome likely provided substrate for cyclic adenosine monophosphate–mediated triggered activity, causing fascicular VT.

BACKGROUND:Left bundle branch area pacing (LBBAP) is a new technique for patients with atrioventricular block (AVB) and preserved left ventricular ejection fraction (LVEF), potentially offering better cardiac function than right ventricular pacing (RVP). METHODS:We searched databases and registries for studies that compared LBBAP with RVP in patients with AVB and preserved LVEF. We extracted data on various outcomes and pooled the effect estimates using random-effects models. RESULTS:Our meta-analysis included 14 studies (10 observational and 4 RCTs) involving 3062 patients with AVB. The analysis revealed that the QRS duration was significantly shorter in the LBBAP group compared to the RVP group [MD = -35.56 ms; 95% CI: (-39.27, -31.85), p < 0.00001]. Patients in the LBBAP group also exhibited a significant increase in left ventricular ejection fraction (LVEF) [MD = 5.48%; 95% CI: (4.07%, 6.89%), p < 0.00001], and a significant reduction in left ventricular end-diastolic diameter (LVEDD) compared to RVP [MD = -3.98 mm; 95% CI: (-5.88, -2.09 mm), p < 0.0001]. In terms of clinical outcomes, LBBAP was associated with a significantly lower risk of heart failure hospitalizations (HFHs) compared to RVP [OR = 0.26; 95% CI: (0.16, 0.44), p < 0.0001]. However, no significant differences were observed between the two groups in the implant success rate, pacing impedance, or pacing threshold. The RVP group demonstrated a significantly higher R-wave amplitude increase than the LBBAP group [MD = 0.85 mV; 95% CI: (0.23, 1.46), p = .007]. Lastly, there was no significant difference in the incidence of complications between the two groups [OR = 2.12; 95% CI: (0.29, 15.52), p = 0.46]. CONCLUSION:LBBAP outperforms RVP in several cardiac function indicators, suggesting it may be a superior pacing method for AVB patients with preserved LVEF. However, the small sample size in studies and the result in heterogeneity call for more research to validate these findings and assess LBBAP's long-term effects.

Antiseizure medications (ASMs) are the primary treatment for epilepsy. However, adverse cardiac effects of ASMs can occur, related to their effects on lipid metabolism, raising ischemic heart disease risk; or specific actions on cardiac ion channels, increasing cardiac arrhythmia risk. Select ASMs, particularly enzyme inducers used at higher doses or for longer durations, can adversely affect lipids or cause metabolic changes, and thereby increase the risk for ischemic heart disease. These metabolic and potentially proarrhythmic actions may contribute to the increased cardiovascular morbidity and mortality that occur in epilepsy. Many ASMs block sodium channels or affect the QT interval, which can lead to proarrhythmia, particularly when used in combination with other medications or given to vulnerable populations. While ASMs are rarely reported to cause cardiac arrhythmias directly, population data raise concerns that cardiac arrhythmias and sudden cardiac death may be more common in epilepsy, and that sodium channel blocking ASMs in particular, might contribute. It is also possible that some cases of sudden cardiac death could be misclassified as sudden unexpected death in epilepsy (SUDEP), leading to an underestimation of the cardiovascular risk in this population. Cardiovascular risk factors, such as smoking and a sedentary lifestyle, are also associated with epilepsy, and should also be addressed. This summary is a narrative review of the literature, clarifies which ASMs tend to have more cardiovascular effects, and provides practical suggestions for medication management and monitoring from neurology and cardiology perspectives.

Ventricular arrhythmias (VAs) affect many patients with heart failure and underlying structural heart disease and are associated with significant morbidity and mortality. Antiarrhythmic drugs are often the initial treatment, but medication alone often fails to sufficiently suppress VAs. While catheter ablation (CA) remains the gold standard for treatment of VAs, CA is an invasive procedure and can be associated with periprocedural complications including acute clinical decompensation. Thus, there is an important need for alternative therapies. Recent advances in risk stratification and the development of new ablation technologies may reduce some of the periprocedural complications and limitations of CA. In addition, less invasive therapies for VAs may provide an alternative treatment strategy for patients in both the acute and chronic setting. For patients acutely admitted with ventricular tachycardia electrical storm (VT-ES) or recurrent VT and cardiogenic shock, risk stratification tools have been developed to identify patients at high risk of acute hemodynamic decompensation during CA. These patients require a multidisciplinary approach and might need mechanical circulatory support (MCS) if CA is selected as the treatment strategy. Alternatively, less invasive therapies targeting the autonomic nervous system may be reasonable. In the chronic setting, developments in medical therapy have reduced the risk of sudden cardiac death in heart failure patients and stereotactic whole-body radiation (SBRT) has evolved as a potential, non-invasive therapy. Further research is needed to personalize VA therapy for individual patients.

A 68-year-old man underwent a diagnostic electrophysiology study because of a symptomatic short RP supraventricular tachycardia (SVT). Transthoracic echocardiography was normal. Atrio-His and His-ventricular intervals measured 70 and 55 ms, respectively. The patient had retrograde ventriculoatrial activation that was earliest only at the anteroseptal right atrium and decremental. Programmed atrial extrastimulation elicited dual atrioventricular (AV) nodal physiology. Rapid atrial pacing repeatedly induced his SVT with an episode of termination shown in Figure 1A. The response to late His-refractory ventricular premature depolarizations (VPDs) delivered from the right ventricular apex is shown in Figure 1B. The responses to VPDs delivered 30 ms earlier are shown in Figures 2A and 2B. On the basis of the information, what is the mechanism of tachycardia? Figure 2A and B: Reproducible responses of tachycardia to 30 ms earlier ventricular premature depolarizations. View Large Image Figure Viewer Download Hi-res image

BACKGROUND:There is limited information on the mode of arrhythmia initiation in idiopathic ventricular fibrillation (IVF). A non-pause-dependent mechanism has been suggested to be the rule. OBJECTIVES:The aim of this study was to assess the mode and characteristics of initiation of polymorphic ventricular tachycardia (PVT) in patients with short or long-coupled PVT/IVF included in THESIS (THerapy Efficacy in Short or long-coupled idiopathic ventricular fibrillation: an International Survey), a multicenter study involving 287 IVF patients treated with drugs or radiofrequency ablation. METHODS:We reviewed the initiation of 410 episodes of ≥1 PVT triplet in 180 patients (58.3% females; age 39.6 ± 13.6 years) with IVF. The incidence of pause-dependency arrhythmia initiation (prolongation by >20 ms of the preceding cycle length) was assessed. RESULTS:Most arrhythmias (n = 295; 72%) occurred during baseline supraventricular rhythm without ambient premature ventricular complexes (PVCs), whereas 106 (25.9%) occurred during baseline rhythm including PVCs. Nine (2.2%) arrhythmias occurred during atrial/ventricular pacing and were excluded from further analysis. Mode of PVT initiation was pause-dependent in 45 (15.6%) and 64 (60.4%) of instances in the first and second settings, respectively, for a total of 109 of 401 (27.2%). More than one type of pause-dependent and/or non-pause-dependent initiation (mean: 2.6) occurred in 94.4% of patients with ≥4 events. Coupling intervals of initiating PVCs were <350 ms, 350-500 ms, and >500 ms in 76.6%, 20.72%, and 2.7% of arrhythmia initiations, respectively. CONCLUSIONS:Pause-dependent initiation occurred in more than a quarter of arrhythmic episodes in IVF patients. PVCs having long (between 350 and 500 ms) and very long (>500 ms) coupling intervals were observed at the initiation of nearly a quarter of PVT episodes.

Abstract Background A recent review of 86 patients with short or long-coupled premature ventricular complex (SLC-PVC) initiating idiopathic ventricular fibrillation (IVF) found high success rate in arrhythmia control with quinidine (QND) (83%) or radiofrequency ablation (RFA) (70.8%). Purpose To compare the efficacy of QND vs. RFA therapy in a large patient cohort with SLC-IVF. Methods THESIS included 287 patients with SLC-IVF screened from 58 centers and 1 multicenter group in 22 countries across 4 continents. The study cohort included 146 (50.9%) males, aged 39+14 years at the time of IVF documentation. Therapy groups were defined according to the first therapy given. Therapy success was defined as no VF recurrence. Results Patients presented after aborted cardiac arrest, ICD shocks, syncope, aborted cardiac arrest + arrhythmic storm, arrhythmic storm, palpitations, seizures or were asymptomatic in 121 (42%), 51(18%), 42(14.6%), 27 (9.4%), 23 (8%), 8 (2.8%), 6 (2.1%) and 9 (3.1%), respectively. Fifty-three patients (18.5%) had a prior history of syncope. Eleven (3.8%) patients required ECMO support. Mean shortest and longest coupling interval which triggered VF in the same patient were 304.9+82ms and 341.2+94.1ms, respectively. VF initiation with "long" coupled PVC (coupling interval >350ms) was observed in 41 (18.1%) patients, and VF initiation with both short and long coupled PVC was documented in 30 (13.2%) others. RFA was performed in 112 patients and QND was given to 68 patients. Patients were followed during a mean follow-up of 84.8+64.5 months. Therapy success was achieved in the RFA or QND group in 69 (62.2%) and 49 (71%) patients, respectively (p=0.29). The RV Purkinje was the main targeted ablation site in 46 (47.4%) patients. Treatment success varied according to the site of origin (SOO) of the PVC which triggered VF. Therapy success was higher with QND when PVC SOO based on ECG, was the RV inflow tract (81.3% vs. 57.7%, p=0.048) or when the SOO was not available (67.9% vs 36.4%, p=0.064), and when the coupling interval/QT ratio was <1 (75.5% vs. 57.5%, p=0.03), Figures 1,2. A higher success rate with ablation compared with QND was seen with LV- SOO compared with RV-SOO (82.1% vs 60.3%, p=0.019). Similarly, successful ablation was achieved in 83.3% (n=24) vs. 55.9% (n=68) patients with LV and RV-SOO respectively; p=0.004. One patient expired of sudden cardiac death due to misdiagnosis, while wearing a subcutaneous -ICD, without any drug or ablation therapy. Conclusions SLC-IVF strikes males and females equally. SLC-PVCs triggering the arrhythmia mainly arise from the RV Purkinje system. QND and RFA have similar efficacy in arrhythmia control. Quinidine has a higher treatment success rate in patients with PVC-SOO in the RV inflow area and in those with coupling interval/QT<1.Figure 1Treatment success by SOOFigure 2Treatment success by CI/QT

Background Atrial fibrillation (AF) is a known risk factor of ischemic stroke, and AF‐related stroke is twice more likely to be fatal. Long‐term cardiac rhythm monitoring using insertable cardiac monitors (ICMs) has greater diagnostic yield compared with conventional monitoring in detecting AF, and the clinical utility of ICMs is established in cryptogenic stroke, strokes attributable to large‐artery atherosclerosis, and strokes attributable to small‐vessel disease. A registry‐based study was conducted to evaluate the inpatient implantation of ICMs and the feasibility of vascular and interventional neurologists as implanters using novel collaborative clinical care pathway for cryptogenic stroke. Methods Multiyear data from a hospital‐based registry at a comprehensive stroke center were reviewed to evaluate inpatient ICM implantation and test feasibility of vascular and interventional neurologists as implanters of ICMs together with cardiology using a novel collaborative care pathway. Reviewed data included the number of ICMs, implantation trend, inpatient versus outpatient setting, time to ICM implantation, inpatient workflow, including defined roles of team members, and AF detection rate. Results A total of 290 ICMs for cryptogenic stroke were implanted when patients were in the hospital and 78 as outpatients after discharge during the study period of 3 years. Most inpatient ICM implants were performed by vascular and interventional neurology (n = 181), and ICM use for cryptogenic stroke increased by 130%. The average time to inpatient ICM implant was 4.1 days, with 77% in 5 days and 95.5% within 10 days poststroke. The average time to out‐patient ICM placement was 57 days. AF detection rate of 36.5% was noted at 24 months with a collaborative care pathway. Conclusion Inpatient implantation of ICMs is feasible and was performed safely and efficiently by vascular and interventional neurology together with cardiology using a collaborative care pathway. An increase in use of ICMs and higher AF detection rates were noted. Findings support innovative efforts to improve access and close the gaps in the delivery of cryptogenic stroke care to ultimately reduce the secondary stroke burden.

In the field of cardiac electrophysiology, there is a universal desire: the discovery of a flawless diagnostic maneuver for supraventricular tachycardias (SVTs). This is not merely a wish but a shared odyssey. To improve diagnostic accuracy and achieve sufficient sensitivity and specificity, numerous diagnostic maneuvers have been proposed. However, each has its limitations and prompts a search for new diagnostic techniques. This continuous cycle of discovery and refinement, which we titled "SVT Quest" is reviewed in chronological sequence. This adventure in diagnosing narrow QRS tachycardia unfolds in 3 steps: Step 1 involves differentiating atrial tachycardia from other SVTs based on the observations such as V-A-V or V-A-A-V response, ΔAA interval, VA linking, the last entrainment sequence, and response to the atrial extrastimulus. Step 2 focuses on differentiating orthodromic reciprocating tachycardia from atrioventricular nodal reentrant tachycardia based on the observations such as tachycardia reset upon the premature ventricular contraction during His refractoriness, uncorrected/corrected postpacing interval, differential ventricular entrainment, orthodromic His capture, transition zone analysis, and total pacing prematurity. Step 3 characterizes the concealed nodoventricular/nodofascicular pathway and His-ventricular pathway-related tachycardia based on observations such as V-V-A response, ΔatrioHis interval, and paradoxical reset phenomenon. There is no single diagnostic maneuver that fits all scenarios. Therefore, the ability to apply multiple maneuvers in a case allows the operator to accumulate evidence to make a likely diagnosis. Let's embark on this adventure!

On December 12, 1901, the first successful transmission of a radio wave signal was made across the Atlantic ocean—a brief sequence of 3 dots representing the Morse code letter "S" sent from Cornwall, England, to Signal Hill in St. John's, Newfoundland, some 2100 miles away. This remarkable feat helped the Italian inventor Guglielmo Marconi earn a share of the Nobel Prize for Physics in 1909 and ushered in an era of what he called "wireless telegraphy." Cardiovascular implantable electronic device lead safety: Harnessing real-world remote monitoring data for medical device evaluationHeart RhythmVol. 20Issue 4PreviewCurrent methods to identify cardiovascular implantable electronic device lead failure include postapproval studies, which may be limited in scope, participant numbers, and attrition; studies relying on administrative codes, which lack specificity; and voluntary adverse event reporting, which cannot determine incidence or attribution to the lead. Full-Text PDF

A 73-year-old man with recurrent symptomatic supraventricular tachycardia (SVT) had undergone right-sided slow pathway ablation for a reported diagnosis of atrioventricular (AV) nodal reentrant tachycardia (AVNRT) at another institution. Because of persistent symptoms despite metoprolol therapy, he underwent repeat electrophysiology study.