Unstable Ventricular Arrhythmias Research Articles

CORONARY FLOW AT REST AND CLINICAL OUTCOMES IN DILATED CARDIOMYOPATHY

CORONARY FLOW AT REST AND CLINICAL OUTCOMES IN DILATED CARDIOMYOPATHY

Cardiac Magnetic Resonance as an Etiological Diagnosis Tool in Recovered Sudden Cardiac Death or Unstable Ventricular Arrhythmia Patients.

Cardiac magnetic resonance (CMR) has an increasing diagnostic relevance in survivors of sudden cardiac death (SCD) or unstable ventricular arrhythmia (UVA) in developed countries. To evaluate retrospectively the additional role of CMR in a developing country where few resources are available, and should be used more effectively. The study included SCD or UVA survivors admitted between 2009 and 2019 at a tertiary academic institution referred to CMR. Demographic, clinical, and laboratory data were collected from the medical records. CMR images and reports were reviewed and their impact on the final etiological diagnosis was determined. A descriptive analysis was performed and p<0.05 established as significant. Sixty-four patients, 54.9±15.4 years old, and 42 (71.9%) males. Most events (81.3%) were out of the hospital and ventricular tachycardia was the most common rhythm. Cardiovascular medications were previously used by 55 patients, and beta-blockers were the most used medications (37.5%). Electrocardiogram had electrical inactive areas in 21.9% and all of them had fibrosis at CMR. Mean left ventricular ejection fraction (LVEF) was 44±14%, with 60.9% ≤50% and only 29.7% ≤35%. Late gadolinium enhancement was identified in 71.9%, with a transmural pattern in 43.8%. Chagas cardiomyopathy was the most common etiology (28.1%), followed by ischemic cardiomyopathy (17.2%). Among 26 without a previously identified etiology, CMR could define it (15 patients - 57%). In accordance with previous studies in developed countries, CMR was capable of increasing etiological diagnosis and identifying the arrhythmogenic substrate, allowing better care in half of the underdiagnosed patients.

“Stable” Asystole In A Patient With Left Ventricular Assist Device

The use of Left Ventricular assist devices (LVADs) for mechanical circulatory support has become a standard therapy for some patients with end-stage heart failure. Although presentation and consequences of ventricular arrhythmias (VA) in LVAD supported patients are well described and often stabilized by the mechanical support, presence of asystole is less commonly reported. Our patient is a 75-year-old male with advanced ischemic cardiomyopathy requiring cardiac resynchronization therapy-defibrillator (CRT-D) and ultimately HeartMate II LVAD. Post implantation, his CRT-D was abandoned after it reached the elective replacement indicator as he had no VAs and was not pacer dependent. He now presented with a new onset of low flow alarms that started earlier in the day. He appeared stable, pleasant and in a humorous mood. He reported lightheadedness but denied syncope. While in the ED, the patient was noted to be asystolic. His mean arterial pressure was in the 50s. Physical exam was unremarkable with the expected LVAD hum and lack of pulses. LVAD parameters revealed decreased Flow (2.5 from baseline 5.1) and Pulsatility Index (2.7 from baseline 4.9). Patient subsequently underwent implantation of a new battery with reactivation of his previously abandoned pacemaker leads with resultant hemodynamic improvement. Ultimately, he was discharged home in stable condition. Discussion: Very few cases of asystolic LVAD patients without immediate hemodynamic collapse are described. Similarly to ventricular arrhythmias, the hypothesized physiology for stability is this quasi-Fontan circulation, where low pulmonary vascular resistance with elevated central venous pressure allows pulmonary vasculature perfusion and left atrial filling. In this case, low flow alarms and decreased PI were due to decreased left ventricular preload in the setting of asystole. Ventricular arrhythmias remain common after LVAD implantation, asystole, as in the present case can equally be an issue. This is particularly true as many of LVAD supported patients have CRT-Ds implanted in the setting of pre-existent left bundle branch blocks, which can progress to complete heart block or asystole. Thus, It might not always be the case that LVAD supported patients don't benefit from maintaining ICD function. Conclusion: Traditionally unstable asystole and ventricular arrhythmia can be well tolerated in the LVAD population due to quasi-Fontan physiology. ICD role in LVAD patients is currently unclear, and should be a part of shared decision making with the patient. Yes, there may be such a thing as, "stable" asystole.

Cardiopulmonary Support During Catheter Ablation of Ventricular Arrhythmias With Hemodynamic Instability: The Role of Inducibility.

Background: Catheter ablation is a treatment option for sustained ventricular tachycardias (VTs) that are refractory to pharmacological treatment; however, patients with fast VT and electrical storm (ES) are at risk for cardiogenic shock. We report our experience using cardiopulmonary support with extracorporeal membrane oxygenation (ECMO) during catheter ablation of VT.Methods: Sixty-two patients (mean age 68 ± 9 years; 94% male) were referred to our center for catheter ablation of repeated episodes of hemodynamically unstable ventricular arrhythmias. ES was defined as the occurrence of three or more VT/ventricular fibrillation episodes requiring electrical cardioversion or defibrillation in a 24-h period. All patients had hemodynamically unstable VTs.Results: Thirty-one patients (group 1) performed catheter ablation without ECMO support and 31 patients (group 2) with ECMO support. At the end of the procedure, ventricular inducibility was not performed in 16 patients of group 1 (52%) due to significant hemodynamic instability. Ventricular inducibility was performed in the other 15 patients (48%); polymorphic VTs were inducible in eight patients. In group 2, VTs were not inducible in 29 patients (93%); polymorphic VTs were inducible in two patients. The median follow-up duration was 24 months. Four patients of group 1 (13%) and five patients of group 2 (16%) died due to refractory heart failure. An implantable cardioverter-defibrillator intervention (shock or antitachycardia pacing) was documented in 13 patients of group 1 (42%) and six patients of group 2 (19%).Conclusions: Extracorporeal membrane oxygenation support during catheter ablation for hemodynamically unstable VTs is a useful tool to prevent acute procedural heart failure and to reduce arrhythmic burden.

Outcomes of in-hospital cardiac arrest in COVID-19 patients: A proportional prevalence meta-analysis.

BackgroundLimited epidemiological data are available on the outcomes of in‐hospital cardiac arrest (CA) in COVID‐19 patients.MethodsWe performed literature search of PubMed, EMBASE, Cochrane, and Ovid to identify research articles that studied outcomes of in‐hospital cardiac arrest in COVID‐19 patients. The primary outcome was survival at discharge. Secondary outcomes included return of spontaneous circulation (ROSC) and types of cardiac arrest. Pooled percentages with a 95% confidence interval (CI) were calculated for the prevalence of outcomes.ResultsA total of 7,891 COVID patients were included in the study. There were 621 (pooled prevalence 8%, 95% CI 4–13%) cardiac arrest patients. There were 52 (pooled prevalence 3.0%; 95% CI 0.0–10.0%) patients that survived at the time of discharge. ROSC was achieved in 202 (pooled prevalence 39%;95% CI 21.0–59.0%) patients. Mean time to ROSC was 7.74 (95% CI 7.51–7.98) min. The commonest rhythm at the time of cardiac arrest was pulseless electrical activity (pooled prevalence 46%; 95% 13–80%), followed by asystole (pooled prevalence 40%; 95% CI 6–80%). Unstable ventricular arrhythmia occurred in a minority of patients (pooled prevalence 8%; 95% CI 4–13%).ConclusionThis pooled analysis of studies showed that the survival post in‐hospital cardiac arrest in COVID patients is dismal despite adequate ROSC obtained at the time of resuscitation. Nonshockable rhythm cardiac arrest is commoner suggesting a non‐cardiac cause while cardiac related etiology is uncommon. Future studies are needed to improve the survival in these patients.

Spatiotemporal differences in precordial electrocardiographic amplitude before and after flecainide provocation are associated with a history of unstable ventricular arrhythmia in Brugada syndrome.

A drug provocation test (DPT) is important for the diagnosis of Brugada syndrome (BrS). The link, however, between dynamic changes of electrocardiography (ECG) features after DPT and unstable ventricular arrhythmia (VA) in BrS remains unknown. Between 2014 and 2019, we assessed 27 patients with BrS (median age: 37.0 [interquartile range, IQR: 22.0-51.0] years; 25 men), including 9 (33.3%) witha history of unstable VA and 18 (66.7%) without. All patients in the study presented with Brugada-like ECG features before DPT. The ECG parameters and dynamic changes (∆) in 12-lead ECGs recorded from the second, third, and fourth intercostal spaces (ICS) before and at 1, 6, 12, 18, and 24 h after DPT (oral flecainide 400 mg) were analyzed. The total amplitude of V1 at the third ICS 18 and 24 h after DPT was significantly lower in patients with a history of unstable VA than in those without. Patients with BrS and unstable VAs had a significantly larger ∆ amplitude of V1 at the second ICS 12 h after DPT than in those without unstable VAs (0.28 [0.18-0.41] mV vs. 0.08 [0.01-0.15] mV, p = .01). A multivariate analysis revealed that the amplitude of V1 at the third ICS 18 and 24 h after DPT and the ∆ amplitude of V1 at the second ICS 12 h after DPT were associated with a history of unstable VA. Nonuniform changes and spatiotemporal differences in precordial ECG features after DPT were observed in patients with BrS and these may be surrogate markers for risk stratification.

Mechanical circulatory support in the management of life-threatening arrhythmia

Life-threatening refractory unstable ventricular arrhythmias in presence of advanced heart failure (HF) may determine haemodynamic impairment. Haemodynamic mechanical support (HMS) in this setting has a relevant role to restore end-organ perfusion. Catheter ablation (CA) of ventricular tachycardia (VT) is effective at achieving rhythm stabilization, allowing patient's weaning from HMS, or bridging to permanent HF treatments. Acute heart decompensation during CA at anaesthesia induction in presence of advanced heart disease, in selected cases requires a preemptive HMS to prevent periprocedure adverse outcomes. Substrate ablation during sinus rhythm (SR) might be an effective strategy of ablation in presence of unstable VTs; however, in a minority of patients, it might have some limitations and might be unfeasible in some settings, including the case of the mechanical induction of several unstable VTs and the absence of ablation targets. In case of the persistent induction of unstable VTs after a previous failure of a substrate-based ablation in SR, a feasible alternative strategy of ablation might be VT activation/entrainment mapping supported by HMS. Multiple devices are available for HMS in the low-output states related to electrical storm and during CA of VT. The choice of the device is not standardized and it is based on the centres' expertise. The aim of this article is to provide an up-to-date review on HMS for the management of life-threatening arrhythmias, in the context of catheter ablation and discussing our approach to manage critical VT patients.

Noninvasive epi-endocardial electrocardiographic imaging of ventricular septal pacing

Noninvasive epi-endocardial ElectroCardioGraphic Imaging (ECGI) allows reconstruction of electrograms and high-resolution visualization of various isoparametric maps based on multichannel ECG recordings and tomography. We aimed to verify the ECGI accuracy during septal ventricular pacing in patients with pre-implanted pacemakers using the new ECGI algorithm.Methods. Ten patients underwent epi-endocardial ECGI mapping (Amycard 01C EP Lab, Amycard LLC, Russia - EP Solutions SA, Switzerland). The iterative Equal Single Layer algorithm (ESL-iterative) and a new Fast Route algorithm in combination with the vector approach (FRA-V) were used to reconstruct isopotential and correlation similarity maps. Geodesic distance between noninvasively reconstructed early activation zone and RV reference pacing sites were measured to evaluate the ECGI accuracy.Results. The mean (SD) geodesic distance between noninvasively identified sites and reference pacing sites was 22 (15) mm for the ESL-iterative and 12 (7) for FRA-V algorithms, median (25-75% IQR) - 23 (8-29) mm and 10 (8-14) mm, respectively. The accuracy of ECGI mapping based on the FRA-V algorithm was significantly better than ESL-iterative algorithm (p=0,01). A detailed visual analysis of correlation similarity and isopotential maps showed significantly more accurate localization of early activation zones using the new FRA-V algorithm.Conclusions. Our study showed the feasibility and accuracy of a novel epi-endocardial ECGI mapping approach to identify early activation zones during septal ventricular pacing using the new FRA-V algorithm. The FRA-V algorithm is significantly better for epi-endocardial ECGI mapping and shows a significant advantage of this technique compared to other non-invasive methods of topical diagnostics. Moreover, simultaneous beat-to-beat mapping of entire ventricular septum allows using this technique for pre-ablation evaluation of unstable and polymorphic ventricular arrhythmia exit sites.

Noninvasive epi-endocardial electrocardiographic imaging of ventricular septal pacing

Noninvasive epi-endocardial ElectroCardioGraphic Imaging (ECGI) allows reconstruction of electrograms and high-resolution visualization of various isoparametric maps based on multichannel ECG recordings and tomography. This study shows results of ECGI accuracy verification based on septal ventricular pacing in patients with pre-implanted pacemakers using new algorithm for solving the inverse problem of electrocardiography.Methods. 10 patients in this study underwent epi-endocardial ECGI mapping (Amycard 01C EP Lab, Amycard LLC, Russia - EP Solutions SA, Switzerland). An iterative Equal Single Layer algorithm (ESL-iterative) and new Fast Route algorithm in combination with vector approach (FRA-V) were used to reconstruct isopotential and correlation similarity maps. Geodesic distance between noninvasively reconstructed early activate zone and RV reference pacing site were measured to evaluate ECGI accuracy.Results. The mean (SD) geodesic distance between noninvasively reconstructed and reference pacing site was 22 (15) mm for ESL-iterative and 12 (7) for FRA-V algorithm, median (25-75% IQR) - 23 (8-29) mm and 10 (8-14) mm respectively. Accuracy of ECGI mapping based on FRA-V algorithm was significantly better than ESL-iterative algorithm (p=0,01). Detailed visual analysis of correlation similarity and isopotential maps showed significantly more accurate localization of early activation zones using new FRA-V algorithm.Conclusions. These results showed a possibility of novel epi-endocardial ECGI mapping to detect early activation zone during septal ventricular pacing with sufficient accuracy (median 10 mm) using new FRA-V algorithm. Therefore, FRA-V algorithm is significantly better for epi-endocardial ECGI mapping and shows a significant advantage of this technique compared to other non-invasive methods of topical diagnostics. Moreover, simultaneous beat-to-beat mapping of entire ventricular septum allows using of this technique for preoperative topical diagnosis of complex unstable and polymorphic ventricular arrhythmias.

Evaluation of ECG Imaging to Map Hemodynamically Stable and Unstable Ventricular Arrhythmias.

ECG imaging (ECGI) has been used to guide treatment of ventricular ectopy and arrhythmias. However, the accuracy of ECGI in localizing the origin of arrhythmias during catheter ablation of ventricular tachycardia (VT) in structurally abnormal hearts remains to be fully validated. During catheter ablation of VT, simultaneous mapping was performed using electroanatomical mapping (CARTO, Biosense-Webster) and ECGI (CardioInsight, Medtronic) in 18 patients. Sites of entrainment, pace-mapping, and termination during ablation were used to define the VT site of origin (SoO). Distance between SoO and the site of earliest activation on ECGI were measured using co-registered geometries from both systems. The accuracy of ECGI versus a 12-lead surface ECG algorithm was compared. A total of 29 VTs were available for comparison. Distance between SoO and sites of earliest activation in ECGI was 22.6, 13.9 to 36.2 mm (median, first to third quartile). ECGI mapped VT sites of origin onto the correct AHA segment with higher accuracy than a validated 12-lead ECG algorithm (83.3% versus 38.9%; P=0.015). This simultaneous assessment demonstrates that CardioInsight localizes VT circuits with sufficient accuracy to provide a region of interest for targeting mapping for ablation. Resolution is not sufficient to guide discrete radiofrequency lesion delivery via catheter ablation without concomitant use of an electroanatomical mapping system but may be sufficient for segmental ablation with radiotherapy.

VALIDATION OF NONINVASIVE EPI- ENDOCARDIAL ELECTROCARDIOGRAPHIC IMAGING ACCURACY USING RIGHT VENTRICULAR ENDOCARDIAL PACING

Invasive electroanatomical mapping of polymorphic and unstable ventricular arrhythmias is a complex and laborious task. Noninvasive epi-endocardial ElectroCardioGraphic Imaging (ECGI) is a novel beat-to-beat mapping technique. The present work is a second part of single-center single-blind cross-sectional study to verify epi-endocardial ECGI accuracy. This part is particularly dedicated to investigate ECGI accuracy during right ventricular endocardial pacing followed by polygon model quality assessment and detailed analysis of cumulative effect of many different factors.Methods.37 patients with previously implanted pacemakers were enrolled in the study. All patients underwent epiendocardial ECGI mapping (Amycard 01C EP Lab, Amycard LLC, Russia - EP Solutions SA, Switzerland) during right endocardial ventricular pacing. The data obtained from torso and ECG-gated cardiac computed tomography (Somatom Definition 128, Siemens AG, Germany) were used to create three-dimensional ventricular models. Geodesic distance between noninvasively reconstructed early activate zone on the isopotential maps and RV reference pacing site were measured to evaluate ECGI accuracy for each patient.Results.The mean (SD) geodesic distance between noninvasively reconstructed and reference pacing site was 23 (14) mm for RV epicardial models and 9 (12) for RV endocardial surface of epi-endocardial models, median (25-75% IQR) - 21 (11-32) мм and 4 (2-8) mm respectively. ECGI accuracy on RV endocardial surface of epi-endocardial models was significantly better than on epicardial models (p &lt;0,001). At the same time, there were no significant associations between cardiac CT, pacing parameters, clinical characteristics and accuracy values.Conclusions.The main results showed a possibility of novel epi-endocardial ECGI mapping to detect RV focal arrhythmias with high accuracy (median 3 mm) and to recognize endocardial localization with high percent of probability (more than 94%) comparable with invasive electroanatomical mapping. Therefore, this study confirms sufficient accuracy of epi-endocardial ECGI mapping technology for non-invasive topical diagnosis of RV focal arrhythmias.

P5696The first results from multicentre study of noninvasive epi-endocardial panoramic mapping of ventricular arrhythmias

Abstract Background A noninvasive epi-endocardial panoramic mapping is a promising ECG Imaging technology alternative to catheter-based invasive methods. Some unstable ventricular arrhythmias arising from complex anatomic sites render mapping and ablation difficulties with conventional approach. Objective To assess the use of a noninvasive panoramic mapping for diagnosis and localization of ventricular arrhythmias. Methods 35 patients (20 male, median (25–75%) age – 35 (12–60) years) with polymorphic premature ventricular contractions (PVCs) and 3–5 different QRS morphologies (1500–19000 per day) or monomorphic ventricular tachycardia (VT) were enrolled in the study. Up to 224 body surface electrodes were connected to the noninvasive epi-endocardial electrophysiological system for multichannel ECG recording followed by computed tomography of the heart and torso. The body-surface ECG data were processed using inverse-problem solution software in combination with realistic 3D anatomical models of the heart and torso. The earliest site of activation were determined on isopotential maps for each QRS morphology. On the same day patients underwent catheter ablation of one or two dominant PVC morphologies using 3D electroanatomical mapping system. The site of successful catheter ablation served as final confirmation. Afterwards, electroanatomical maps were exported from Carto 3 system and compared with noninvasive maps using custom written Python-based software. Results In total 47 similar PVC morphologies in 30 patients were mapped using noninvasive and invasive electroanatomical mapping systems, 34 (72%) PVCs were correctly diagnosed and 13 (28%) did not accurately correspond with sites of radiofrequency ablation. In 2 patients with four PVC morphologies an early activation zones were determined as a breakthrough from epi and endocardial surface using noninvasive activation maps. Conclusion Non invasive epi-endocardial panoramic mapping technology is a novel diagnostic method which can be used as an additional pre-procedural tool for topical diagnosis of polymorphic PVCs.

Electrical Storm in Patients with Implantable Cardioverter-defibrillators: A Practical Overview.

Electrical storm (ES) is an increasingly common medical emergency characterized by clustered episodes of sustained ventricular arrhythmias (VAs) that lead to repeated appropriate implantable cardioverter-defibrillator (ICD) therapies. A diagnosis of ES can be made with the occurrence of three or more sustained episodes of VAs, or of three or more appropriate ICD therapies within 24 hours in patients with implanted devices. ES is associated with poor outcomes in patients with structural heart disease, particularly those with severe left ventricular dysfunction. In large clinical trials involving patients with ICDs for primary and secondary prevention, ES appears to be a predictor of cardiac death, with notably higher rates of mortality soon after the event. ES management is challenging and requires special medical attention with accurate patient risk stratification and a multidisciplinary approach that includes the use of pharmacologic therapies such as antiarrhythmic drugs (AADs) and interventional approaches like catheter ablation, surgical ablation, or sympathetic neuromodulation. Initial management involves determining and addressing the underlying ischemia, any electrolyte imbalances, and/or other causative factors. Hemodynamic support needs to be considered in high-risk patients with unstable VAs or those with severe comorbidities such as low left ventricular ejection fraction, advanced New York Heart Association class, and/or chronic pulmonary disease. Following the acute phase of ES, treatment should shift towards maximizing therapeutic efforts to address heart failure, performing revascularization, and preventing subsequent VAs. In the present manuscript, we offer an overview of the most relevant clinical aspects of ES with regard to novel therapeutic strategies.

Apical hypertrophic cardiomyopathy with hemodynamically unstable ventricular arrhythmia – Atypical presentation

We present a patient with asymptomatic apical hypertrophic cardiomyopathy (AHCM) who recently developed cardiac arrhythmias, and shortly discuss the diagnostic modalities, differential diagnosis, and treatment strategy for this condition. AHCM is a rare form of hypertrophic cardiomyopathy, which usually involves the apex of the left ventricle. AHCM can occur with varied presentations such as chest pain, palpitations, dyspnea, syncope, atrial fibrillation, myocardial infarction, embolic events, ventricular fibrillation, and congestive heart failure. The most peculiar electrocardiogram findings are giant T-waves inversion in the precordial leads with left ventricular (LV) hypertrophy. A transthoracic echocardiogram is the initial diagnostic modality in the evaluation of AHCM and shows hypertrophy of the LV apex. Other diagnostic modalities, including left ventriculography, multislice spiral computed tomography, and cardiac magnetic resonance imagings, are also valuable tools. Medications used to manage include verapamil, beta-blockers, and antiarrhythmic agents. An implantable cardioverter defibrillator (ICD) is recommended for high-risk patients.

A Rare Case of Coronary Cameral Fistula from Left Circumflex Artery Draining into the Left Ventricular Apex Presenting as Angina Pectoris: A Case Report

Coronary cameral fistula (CCF) is a very rare coronary anomaly in which a communication exists between one of the coronaries and a cardiac chamber. Most of the times it is an incidental finding detected at the time of a coronary angiography. However, sometimes it can have serious presentation like unstable angina, coronary steal or ventricular arrhythmia. We present a rare case of coronary cameral fistula arising from left circumflex artery (LCx) draining in to left ventricular (LV) apex and presenting as unstable angina.

Association of Decreased Right Ventricular Strain with Worse Survival in Non–Acute Coronary Syndrome Angina

Regional strain by speckle-tracking echocardiography can be used to detect occult right ventricular (RV) myocardial dysfunction. However, in patients with coronary artery disease, the impact of RV strain is unknown. The aim of this study was to validate the prognostic value of RV strain in patients with non-acute coronary syndrome angina. In total, 208 patients with coronary artery disease proved by coronary angiography were retrospectively identified (mean age, 63.81±10.12years; 161 men). In addition to clinical and traditional echocardiographic parameters, RV free wall longitudinal strain (RVLS_FW) was measured using speckle-tracking echocardiography from the apical four-chamber view. Cardiac mortality and major cardiovascular events were recorded. During follow-up (23.1±6.6months), 27 patients (12.98%) died of cardiovascular causes. These patients were found to have lower left ventricular ejection fractions and greater reductions in the amplitudes of left ventricular peak systolic global longitudinal strain and RVLS_FW. Using -18% as a cutoff point for RV strain, patients with strain≤-18% had superior outcomes (log-rank χ(2)=9.04 and 6.94 for cardiovascular mortality and arrhythmia, respectively, P=.003). In Cox multivariate regression analysis, RVLS_FW was an independent prognostic factor for both cardiovascular mortality (hazard ratio, 1.27; 95% CI, 1.03-1.72; P=.01) and hemodynamically unstable ventricular arrhythmia (hazard ratio, 1.72; 95% CI, 1.08-2.41; P=.01). RVLS_FW is significantly related to cardiovascular outcomes and hemodynamically unstable ventricular arrhythmia in patients with non-acute coronary syndrome angina.

ECG screening in athletes: optional or mandatory?

ECG screening in athletes: optional or mandatory?

Optimal antiarrhythmic drug therapy for electrical storm.

Electrical storm, defined as 3 or more separate episodes of ventricular tachycardia or ventricular fibrillation within 24 hours, carries significant morbidity and mortality. These unstable ventricular arrhythmias have been described with a variety of conditions including ischemic heart disease, structural heart disease, and genetic conditions. While implantable cardioverter defibrillator implantation and ablation may be indicated and required, antiarrhythmic medication remains an important adjunctive therapy for these persons.

Noise versus signal: the clinical implications of an increasingly sensitive troponin assay for patients with suspected acute coronary syndrome.

To evaluate the clinical impact of a troponin assay switch in suspected acute coronary syndromes (ACS). Retrospective analysis of ACS cases in the 3 months before and after changing to a contemporary, higher sensitivity troponin assay. Admitting diagnosis, proportion with a positive result, initial treatment and testing, coronary artery intervention, inhospital events, and final discharge diagnosis were compared by assay group. Seven hundred seventy patients were included: 319 (41.4%) preassay and 451 (58.6%) postassay. Preassay change, non-ST segment elevation myocardial infarction at admission (43.0% vs. 70.5%; diff [95% confidence interval (CI)] = -27.5 [-34.2, -20.6]) was diagnosed less often, and a positive troponin was less common (33.2% vs. 72.3%; diff [95% CI] = -39.1 [-45.4, -32.2]). However, anticoagulation (53.3% vs. 42.4%; diff [95% CI] = 10.9 [3.8, 18.0]) and cardiac catheterization use were more frequent (53.9% vs. 41.9%; diff [95% CI] = 12.0 [19.0, 48.5]). There was no difference in coronary intervention (41.9% vs. 40.7%; diff [95% CI] = 1.2 [-9.0, 11.2]) by assay period. Inhospital event were rare (unstable ventricular arrhythmia = 1.2%, cardiac arrest = 3.4%, death = 4.4%) with no difference between groups. A non-ACS diagnosis at discharge was more common in the postassay group (31.6% vs. 46.5%; diff [95% CI] = 14.9 [7.9, 21.6]). Although non-ST segment elevation myocardial infarction diagnosis at admission and a positive troponin were more frequent postassay change, rates of anticoagulation and cardiac catheterization were lower and a non-ACS diagnosis at discharge was more common. These data suggest an evolving understanding and clinical impact of contemporary troponin assays when used in real-world settings.

Risk stratification of arrhythmogenic right ventricular cardiomyopathy based on signal averaged electrocardiograms

BackgroundSignal averaged electrocardiogram (SAECG) is a specific and non-invasive tool useful for arrhythmogenic right ventricular cardiomyopathy (ARVC) diagnosis. However, its role in risk stratification of patients with ARVC remains largely undefined. MethodsSixty-four patients fulfilling Task Force ARVC criteria (mean age: 47±14years-old, 56% male, 50% definite ARVC) were enrolled. The baseline demographic, electrocardiographic, structural, and electrophysiological characteristics were collected. Patients with SAECG fulfilling all 3 Task Force criteria (3+ SAECG) were categorized into group 1, and those fulfilled 2 or less criterion were categorized into group 2. The study endpoints were unstable ventricular arrhythmia (VA), device detectable sustained fast VA (cycle lengths <240ms) and cardiovascular death. ResultsDuring a mean follow-up of 21±20months, 15 primary endpoints including 12 unstable VAs and 3 device-detected fast VAs were met. One patient died of electrical storm, and one patient underwent heart transplantation. The presence of 3+ SAECG predicted malignant events in all patients with definite and non-definite ARVC (p<0.01, OR=30.5, 95% CI=2.5–373.7) and in patients with definite ARVC alone (p=0.03, OR=11.1, 95% CI=1.3–93.9). Patients diagnosed with non-definite ARVC without 3+ SAECG were free from malignant events. ConclusionsSAECG fulfilling all 3 Task Force criteria was an independent risk predictor of malignant events in ARVC patients. SAECG may play a valuable role in ARVC risk stratification.