Sustained Monomorphic Ventricular Tachycardia Research Articles

AN UNUSUAL LEFT VENTRICULAR APICAL MASS COMPLICATING ACUTE MYOCARDIAL INFARCTION

Abstract An 34–year–old man presented to the emergency department of our hospital with palpitations and presyncope. He was a smoker but had no others known cardiovascular risk factors. At admission, his electrocardiogram (ECG) showed sustained monomorphic ventricular tachycardia (VT) at a rate of 187 beats per minute. The VT was successfully treated with synchronized direct current cardioversion. The ECG in sinus rhythm showed Qs from V1 to V6 with ventricular repolarization anomalies in the same site suspicious for previous anterior necrosis. A transthoracic echocardiogram revealed akinetic apex, akinesia of middle segments of the interventricular septum, anterior and lateral walls, Left Ventricular (LV) ejection fraction of 30% and a large apical mass suspicious for LV thrombus. The patient was admitted to the coronary care unit and taken to the Cath lab that showed total left anterior descending mid–segment occlusion. Due to the chronicity of the condition, the patient was recommended to optimal medical therapy. Suspecting LV thrombus, the patient began treatment with unfractionated heparin i.v. and subsequently imbricate therapy with enoxaparin s.c. and warfarin. Additionally, the patient underwent subcutaneous implantable cardioverter defibrillator (S–ICD) implantation for secondary prevention of sudden cardiac death. At echocardiographic follow–up one week after discharge, the apical mass remained unchanged despite warfarin therapy with INR at target. For this reason, the patient was recommended to perform a Cardiovascular magnetic resonance (CMR). Three months after S–ICD implantation, a CMR was performed which showed transmural areas of late gadolinium enhancement involving all apical segments and middle segments of the interventricular septum which allowed the diagnosis of a large intramyocardial dissecting hematoma (IDH) of left ventricle. IDH is a rare complication of ST–elevation myocardial infarction (STEMI), it is an unusual form of subacute cardiac rupture and could be fatal. It usually consists of a cavity or channels within the myocardium. Its prognosis varies according to its location, but generally apical IDH have more favorable outcome with a higher likelihood of spontaneous retraction. We report this case because the IDH is a diagnostic challenge and it represents an extremely rare and poorly described event in the literature.

Competing Risks for Monomorphic versus Non-Monomorphic Ventricular Arrhythmias in Primary Prevention Implantable Cardioverter Defibrillator Recipients: Global Electrical Heterogeneity and Clinical Outcomes (GEHCO) Study.

Ablation of monomorphic ventricular tachycardia (MMVT) has been shown to reduce shock frequency and improve survival. We aimed to compare cause-specific risk factors of MMVT and polymorphic ventricular tachycardia (PVT)/ventricular fibrillation (VF) and to develop predictive models. The multicenter retrospective cohort study included 2,668 patients (age 63.1±13.0 y; 23% female; 78% white; 43% nonischemic cardiomyopathy, left ventricular ejection fraction 28.2±11.1%). Cox models were adjusted for demographic characteristics, heart failure severity and treatment, device programming, and ECG metrics. Global electrical heterogeneity was measured by spatial QRS-T angle (QRSTa), spatial ventricular gradient elevation (SVGel), azimuth, magnitude (SVGmag), and sum absolute QRST integral (SAIQRST). We compared the out-of-sample performance of the lasso and elastic net for Cox proportional hazards and the Fine-Gray competing risk model. During a median follow-up of 4 years, 359 patients experienced their first sustained MMVT with appropriate ICD therapy, and 129 patients had their first PVT/VF with appropriate ICD shock. The risk of MMVT was associated with wider QRSTa (HR 1.16; 95%CI 1.01-1.34), larger SVGel (HR 1.17; 95%CI 1.05-1.30), and smaller SVGmag (HR 0.74; 95%CI 0.63-0.86) and SAIQRST (HR 0.84; 95%CI 0.71-0.99). The best-performing 3-year competing risk Fine-Gray model for MMVT (ROC(t)AUC 0.728; 95%CI 0.668-0.788) identified high-risk (> 50%) patients with 75% sensitivity, 65% specificity, and PVT/VF prediction model had ROC(t)AUC 0.915 (95%CI 0.868-0.962), both satisfactory calibration. We developed and validated models to predict the competing risks of MMVT or PVT/VF that could inform procedural planning and future RCTs of prophylactic VT ablation.

Serial Cardiac Magnetic Resonance Imaging in Patients with Mitral Valve Prolapse-A Single-Center Retrospective Registry.

Background: Mitral valve prolapse (MVP) and mitral annular disjunction (MAD) are common valvular abnormalities that have been associated with ventricular arrhythmias (VA). Cardiac magnetic resonance imaging (CMR) has a key role in risk stratification of VA, including assessment of late gadolinium enhancement (LGE). Methods: Single-center retrospective analysis of patients with MVP or MAD who had >1 CMR and >1 24 h Holter registration available. Data are presented in detail, including evolution of VA and presence of LGE over time. Results: A total of twelve patients had repeated CMR and Holter registrations available, of which in four (33%) patients, it was conducted before and after minimal invasive mitral valve repair (MVR). After a median of 4.7 years, four out of eight (50%) patients without surgical intervention had new areas of LGE. New LGE was observed in the papillary muscles and the mid to basal inferolateral wall. In four patients, presenting with syncope or high-risk non-sustained ventricular tachycardia (VT), programmed ventricular stimulation was performed and in two (50%), sustained monomorphic VT was easily inducible. In two patients who underwent MVR, new LGE was observed in the basal inferolateral wall of which one presented with an increased burden of VA. Conclusions: In patients with MVP and MAD, repeat CMR may show new LGE in a small subset of patients, even shortly after MVR. A subgroup of patients who presented with an increase in VA burden showed new LGE upon repeat CMR. VA in patients with MVP and MAD are part of a heterogeneous spectrum that requires further investigation to establish risk stratification strategies.

Cardiac Sarcoidosis Presenting as Sustained Ventricular Tachycardia.

Sarcoidosis has many possible clinical presentations since it can affect any organ, most commonly the lungs. The hallmark of the disease consists of the formation of non-necrotising granulomas. Pathogenesis is thought to rely on the interplay of genetic, environmental and epigenetic factors. This case highlights the importance of a thorough clinical history and physical examination, and the correlation with imaging findings in the diagnostic work-up of the non-ischaemic cardiomyopathy. A 57-year-old woman was admitted due to the sudden onset of malaise, dizziness, and chest discomfort. Sustained monomorphic ventricular tachycardia was evidenced and the patient rapidly evolved with haemodynamic instability; she underwent successful electrical cardioversion. The electrocardiogram afterwards showed a high-risk electrocardiographic pattern. Invasive coronary angiography excluded obstructive epicardial coronary lesions. Physical examination revealed skin lesions on the lower limbs which raised suspicion for erythema nodosum and therefore a biopsy was performed. Transthoracic echocardiography and cardiac magnetic resonance imaging revealed features consistent with an inflammatory cardiomyopathy, and an implantable cardioverter-defibrillator was placed. The histologic examination of the cutaneous lesions showed a non-necrotising granulomatous inflammatory process. Radionuclide imaging was inconclusive. The patient underwent an endomyocardial biopsy, which confirmed the diagnosis of systemic sarcoidosis with cardiac involvement. Systemic sarcoidosis with cardiac involvement is a challenging diagnosis. The role of imaging techniques such as transthoracic echocardiography, cardiac magnetic resonance imaging and radionuclide imaging is essential in raising suspicion and diagnosing this pathology. Endomyocardial biopsy is the 'gold standard' for its diagnosis; however, it has a low diagnostic yield. Systemic sarcoidosis with cardiac involvement is a challenging diagnosis as it may present in many different ways.The case presented highlights the importance of a thorough clinical history and physical examination, and the correlation with imaging findings.Imaging techniques such as transthoracic echocardiogram, cardiac magnetic resonance and radionuclide imaging are essential in raising suspicion and diagnosing cardiac sarcoidosis.

Incidence and Predictors for Recurrence of Ventricular Arrhythmia Presenting During Acute Myocarditis: A Multicenter Study.

Management of acute myocarditis (AM) patients experiencing ventricular arrhythmia (VA) during acute illness is controversial, especially regarding early implantable cardioverter-defibrillator (ICD) implantation. The purpose of this study was to evaluate the prevalence of and find predictors for long-term sustained VA recurrence and overall mortality among AM patients with VA. This was a multicenter retrospective analysis of AM patients (verified by cardiac magnetic resonance imaging or myocardial biopsy) with documented VA during the acute illness ("initial VA"). Patients with history of myocardial infarction, heart failure, or VA were excluded. The study endpoint was a composite of sustained VA and overall mortality during follow-up. The study included 69 AM patients with initial VA: sustained monomorphic ventricular tachycardia (MMVT) (n=25), sustained polymorphic ventricular tachycardia (VT)/ventricular fibrillation (n=13), and nonsustained VT (n=31). Age was 44 ± 13 years, and 23 of 69 (33.3%) were women. During median follow-up of 5.5 years, 27 of 69 (39%) patients reached the composite endpoint including sustained VA (n=24) and death (n=11). Initial MMVT, predischarge left ventricular dysfunction (left ventricular ejection fraction<50%), and anteroseptal delayed enhancement on cardiac magnetic resonance imaging were significantly associated with the composite endpoint. On multivariable analysis, initial MMVT (HR: 5.17; 95%CI: 1.81-14.6; P=0.001) and predischarge LV dysfunction (HR: 4.57; 95%CI: 1.83-11.5; P=0.005) were independently associated with the composite endpoint. Using these 2 predictors, we could delineate subgroups with low (∼4%), medium (∼42%), and high (∼82%) 10-year incidence of composite endpoint. AM patients presenting with VA have high incidence of sustained VA recurrence and mortality posthospitalization. Initial MMVT and predischarge LV dysfunction are independently associated with VA recurrence and mortality. Implantable cardioverter-defibrillator implantation may be considered in such high-risk patients.

Sinus rhythm activation signature indicates reentrant ventricular tachycardia inducibility and approximate isthmus location

BackgroundSinus rhythm activation time is useful to assess infarct border zone substrate. ObjectiveWe sought to further investigate sinus activation in ventricular tachycardia (VT). MethodsCanine postinfarction data were analyzed retrospectively. In each experiment, an infarct was created in the left ventricular wall by left anterior descending coronary artery ligation. At 3 to 5 days after ligation, 196–312 bipolar electrograms were recorded from the anterior left ventricular epicardium overlapping the infarct border zone. Sustained monomorphic VT was induced by premature electrical stimulation in 50 experiments and was noninducible in 43 experiments. Acquired sinus rhythm and VT electrograms were marked for electrical activation time, and activation maps of representative sinus rhythm and VT cycles were constructed. The sinus rhythm activation signature was defined as the cumulative number of multielectrode recording sites that had activated per time epoch, and its derivative was used to predict VT inducibility and to define the sinus rhythm slow/late activation sequence. ResultsPlotting mean activation signature derivative, a best cutoff value was useful to separate experiments with reentrant VT inducibility (sensitivity, 42/50) vs noninducibility (specificity, 39/43), with an accuracy of 81 of 93. For the 50 experiments with inducible VT, recording sites overlying a segment of isochrone encompassing the sinus rhythm slow/late activation sequence spanned the VT isthmus location in 32 cases (64%), partially spanned it in 15 cases (30%), but did not span it in 3 cases (6%). ConclusionThe sinus rhythm activation signature derivative is assistive to differentiate substrate supporting reentrant VT inducibility vs noninducibility and to identify slow/late activation for targeting isthmus location.

Programmed Ventricular Stimulation: Risk Stratification and Guiding Antiarrhythmic Therapies.

Electrophysiologic testing with programmed ventricular stimulation (PVS) has been utilized to induce ventricular tachycardia (VT), thereby improving risk stratification for patients with ischemic and nonischemic cardiomyopathies and determining the effectiveness of antiarrhythmic therapies, especially catheter ablation. A variety of procedural aspects can be modified during PVS in order to alter the sensitivity and specificity of the test including the addition of multiple baseline pacing cycle lengths, extrastimuli, and pacing locations. The definition of a positive result is also critically important, which has varied from exclusively sustained monomorphic VT (>30 seconds) to any ventricular arrhythmia regardless of morphology. In this review, we discuss the history of PVS and evaluate its role in sudden cardiac death risk stratification in a variety of patient populations. We propose an approach to future investigations that will capitalize on the unique ability to vary the sensitivity and specificity of this test. We then discuss the application of PVS during and following catheter ablation. The strategies that have been utilized to improve the efficacy of intraprocedural PVS are highlighted during a discussion of the limitations of this probabilistic strategy. The role of noninvasive programmed stimulation is also reviewed in predicting recurrent VT and informing management decisions including repeat ablations, modifications in antiarrhythmic drugs, and implantable cardioverter-defibrillator programming. Based on the available evidence and guidelines, we propose an approach to future investigations that will allow clinicians to optimize the use of PVS for risk stratification and assessment of therapeutic efficacy.

Intramural needle ablation or repeated standard ablation in patients referred for repeat ablation of scar-related ventricular tachycardia.

When ventricular tachycardia (VT) recurs after standard RF ablation (sRFA) some patients benefit from repeat sRFA, whereas others warrant advanced methods such as intramural needle ablation (INA). Our objectives are to assess the utility of repeat sRFA and to clarify the benefit of INA when repeat sRFA fails in patients with VT due to structural heart disease. In consecutive patients who were prospectively enrolled in a study for INA for recurrent sustained monomorphic VT despite sRFA, repeat sRFA was considered first. INA was performed during the same procedure if repeat sRFA failed or no targets for sRFA were identified. Of 85 patients enrolled, acute success with repeat sRFA was achieved in 30 patients (35%), and during the 6-month follow-up, 87% (20/23) were free of VT hospitalization, 78% were free of any VT, and 7 were lost to follow-up. INA was performed in 55 patients (65%) after sRFA failed, or no endocardial targets were found abolished or modified inducible VT in 35/55 patients (64%). During follow-up, 72% (39/54) were free of VT hospitalization, 41% were free of any VT, and 1 was lost to follow-up. Overall, 59 out of 77 (77%) patients were free of hospitalization and 52% were free of any VT. Septal-origin VTs were more likely to need INA, whereas RV and papillary muscle VTs were less likely to require INA. Repeat sRFA was beneficial in 23% (18/77) of patients with recurrent sustained VT who were referred for INA. The availability of INA increased favorable outcomes to 52%.

Multidetector Computed Tomography Assessment of Anatomical Ventricular Tachycardia Isthmuses in Repaired Tetralogy of Fallot

BackgroundTetralogy of Fallot (TOF) is associated with risk for sustained monomorphic ventricular tachycardia (VT). Preemptive electrophysiology study before transcatheter pulmonary valve placement is increasing, but the value of MDCT for anatomical VT isthmus assessment is unknown. ObjectivesThe purpose of this study was to determine the impact of multidetector computed tomography (MDCT) in the evaluation of sustained monomorphic VT for repaired TOF. MethodsConsecutive pre–transcatheter pulmonary valve MDCT studies were identified, and anatomical isthmus dimensions were measured. For a subset of patients with preemptive electrophysiology study, MDCT features were compared with electroanatomical maps. ResultsA total of 61 repaired TOFs with MDCT were identified (mean 35 ± 14 years, 58% men) with MDCT electroanatomical map pairs in 35 (57%). Calcification corresponding to patch material was present in 46 (75%) and was used to measure anatomical VT isthmuses. MDCT wall thickness correlated positively with number of ablation lesions and varied with functional isthmus properties (blocked isthmus 2.6 mm [Q1, Q3: 2.1, 4.0 mm], slow conduction 4.8 mm [Q1, Q3: 3.3, 6.0 mm], and normal conduction 5.6 mm [Q1, Q3: 3.9, 8.3 mm]; P < 0.001). A large conal branch was present in 6 (10%) and a major coronary anomaly was discovered in 3 (5%). Median ablation lesion distance was closer to the right vs the left coronary artery (10 mm vs 15 mm; P = 0.01) with lesion-to-coronary distance <5 mm in 3 patients. ConclusionsMDCT identifies anatomical structures relevant to catheter ablation for repaired TOF. Wall thickness at commonly targeted anatomical VT isthmuses is associated with functional isthmus properties and increased thermal energy delivery.

Ventricular tachycardia ablation after myocardial infarction guided by cardiac magnetic resonance/multidetector computed tomography image integration

Abstract INTRODUCTION The persistent challenge of ventricular tachycardia (VT) ablation lies in the elevated morbidity and mortality due to the underlying disease progression and the complexity of the arrhythmogenic substrate. As imaging methods are evolving, substrate-based VT ablation is moving closer to the realm of precision medicine. CASE PRESENTATION A 52-year-old patient with a history of hypertension, type II diabetes mellitus, hyperlipidemia, and stage IIIB chronic kidney disease was referred to our hospital for sustained monomorphic VT. Upon admission, the patient was hemodynamically stable. Laboratory results indicated mild anemia, moderate renal dysfunction, and normal myocardial enzymes. ECG during sinus rhythm showed widespread repolarization abnormalities in the apical and postero-lateral leads. Echocardiography revealed mild left ventricular dysfunction and coronary angiography confirmed significant lesions in multiple coronary arteries that were treated with drug-eluting stents (DES). Cardiac MRI showed relatively limited areas of old myocardial infarctions in the left circumflex artery and left anterior descending artery territories, therefore we decided to perform VT ablation. We used a Carto 3 Biosense Webster electro-anatomical mapping system (EAM) guided by fusion imaging (cardiac MRI and multidetector computed tomography - MDCT) with the aid of ADAS 3D software. The voltage map created during sinus rhythm, was concordant with the lesions identified on LGE-CMR. Radiofrequency (RF) catheter ablation targeted abnormal signals from the EAM, which were identified based on conduction channels (CCs) from the fusion imaging. There was complete VT non-inducibility at programmed ventricular stimulation (PVS). At the 3-month follow-up, echocardiography showed a slight improvement in LVEF and repeated PVS proved persistent ventricular arrhythmia non-inducibility. CONCLUSION Substrate-based VT ablation in structural heart disease has greatly improved by high-resolution substrate imaging with detailed anatomy, allowing successful personalized treatment. There is room for further improvement in the near future with the contribution of artificial intelligence, possibly with a more targeted and automated VT ablation.

Development and clinical value of programmed ventricular stimulation in coronary artery disease and dilated cardiomyopathy

Programmed ventricular stimulation (PVS), aclinical tool introduced in the early 1980s, aims to prove the electrical vulnerability of the heart and, independent of spontaneous arrhythmia variability, to trigger arrhythmias under controlled conditions. Aspecific response is the inducibility of monomorphic sustained ventricular tachycardia. This depends on the underlying heart disease, e.g., only for coronary artery disease but not for nonischemic diseases. The value of pharmacologic arrhythmia control as serial electrical testing is uncertain. Up to now there seems to be no prognostic value of PVS concerning sudden cardiac death. PVS is used as atool to monitor the results of ventricular tachycardia (VT)-catheter ablation in patients who were primarily inducible.

MSA-VT Score for Assessment of Long-Term Prognosis after Electrical Storm Ablation.

Prognosis after electrical storm (ES) ablation remains severe, especially in patients with recurrent sustained monomorphic ventricular tachycardia (SMVT) or progressive heart failure (HF). However, single-factor-based prediction is suboptimal and may be refined by more complex algorithms. We sought to evaluate if a novel score MSA-VT (M = moderate/severe mitral regurgitation, S = severe HF at admission, A = atrial fibrillation at admission, VT = inducible SMVT after ablation) may improve prediction of death and recurrences compared to single factors and previous scores (PAINESD, RIVA and I-VT). A total of 101 consecutive ES ablation patients were retrospectively analyzed over a 32.8-month (IQR 10-68) interval. The MSA-VT score was calculated as the sum of the previously mentioned factors' coefficients based on hazard ratio values in Cox regression analysis. The AUC for death prediction by MSA-VT was 0.84 (p < 0.001), superior to PAINESD (AUC 0.63, p = 0.03), RIVA (AUC 0.69, p = 0.02) and I-VT (0.56, p = 0.3). MSA-VT ≥ 3 was associated with significantly higher mortality during follow-up (52.7%, p < 0.001). Prediction by single factors and previously published scores after ES ablation may be improved by the novel MSA-VT score; however, this requires further external validation in larger samples.

Complex Substrate Leading to PVC-Mediated Systolic Dysfunction in addition to Sustained Monomorphic VT in Repaired Tetralogy of Fallot.

Frequent premature ventricular complexes (PVCs) are associated with deleterious effects on left ventricular (LV) function in various clinical scenarios. Repaired tetralogy of Fallot (rTOF) is frequently affected by sustained ventricular arrhythmias dependent on complex post-surgical substrates. However, there is limited data regarding the potential of arrhythmogenic isthmuses to generate frequent PVCs and PVC-mediated LV systolic dysfunction development in rTOF. We present a case of rTOF experiencing relatively infrequent episodes of internal shocks for episodes of sustained monomorphic ventricular tachycardia and a high burden of PVCs associated with left ventricular systolic function deterioration, in which the successful substrate ablation of the anatomical VT isthmuses also led to PVC abolition and consequently to LV systolic function normalization. In such cases, understanding the pathogenic mechanisms that lead to LV dysfunction is only possible by rigorous clinical reasoning, which leads to a tailored specific treatment.

Sudden sustained monomorphic ventricular tachycardia in a previously healthy adult with many causes for it, but which one is the correct? A case report

Introduction. Sustained monomorphic ventricular tachycardia (VT) ? SMVT is a rare, underdiagnosed pathology with a very poor prognosis. Along with ventricular fibrillation, SMVT is responsible for nearly all of the arrhythmic sudden cardiac deaths (SCD). The most common cause of VT is ischemic heart disease, but there are many other reasons, among which are arrhythmogenic right ventricular cardiomyopathy (ARVD) and myocardial bridging phenomenon. Treatment options include a hybrid approach consisting of antiarrhythmic drugs, catheter ablation, and implantable cardioverter defibrillators (ICD). Case report. We present a case of a 46-year-old man, a military officer, who experienced chest pain, palpitations, and nausea during regular physical activity at home. Due to the symptoms described, he was examined immediately and diagnosed with SMVT. Shortly after the diagnosis, he lost consciousness and was successfully resuscitated. A complete non-invasive and invasive cardiology examination was performed. It revealed that the patient had stable coronary disease and a muscle bridge on the left anterior descending artery. An ARVD was suspected after transthoracic echocardiography and heart magnetic resonance imaging. Genetic testing for ARVD was negative, but according to the Heart Rhythm Society expert consensus criteria, we had enough for a definitive diagnosis. The patient was hospitalized for ten days and treated with drugs without recurring VT or other disorders. We implanted an implantable loop recorder before the discharge and monitored the heart rhythm for one year. During a three-year follow-up, all of his electrocardiographic findings presented sinus rhythm without heart rhythm disorders. Conclusion. Sudden SMVT is the most common cause of SCD. It is of inestimable importance to carry out a detailed examination and determine the immediate cause of the arrhythmia and the right therapy, which, for these patients, is a life-saving form of treatment. Therapy includes medications, electrophysiology or ICD, or a combination of these treatment approaches.

The R'' wave in V1 and the terminal QRS vector in aVF combine to a novel 12-lead ECG algorithm to identify slow conducting anatomical isthmus 3 in patients with tetralogy of Fallot

Abstract Background Patients with repaired tetralogy of Fallot (rTOF) have an increased risk for ventricular tachycardia (VT), with slow conducting anatomical isthmus (SCAI) 3 as the dominant VT substrate. Right bundle branch block (RBBB) is common in these patients. SCAI 3 can lead to additional activation delay affecting the terminal RV activation.(1) We hypothesize that these alterations can be detected by sinus rhythm (SR) 12-lead ECG. Purpose To develop a novel algorithm to non-invasively identify SCAI 3 with the SR 12-lead ECG in rTOF patients with RBBB. Methods Consecutive rTOF patients aged ≥16 years old with RBBB who underwent electroanatomical mapping (EAM) at our institution between 2017-2022, and 2010-2016, comprised the derivation, and validation cohort, respectively. 12-lead ECGs in SR were analyzed for presence of R’’ wave in V1 (any positive deflection after R’ in V1) and for duration of a negative terminal QRS portion (NTP) in aVF (ms between QRS complex traversing the isoelectric line from positive to negative vector until QRS offset) (Figure, A). Results Forty-six rTOF patients (aged 40±15 years, 70% male) comprised the derivation cohort. Patients were repaired at a median age of 3.3 [IQR 1.2-6.6] years via a ventricular incision in 21 (55%). Mean QRS duration was 165±23ms and 12 (26%) had a QRS duration of ≥180ms. SCAI 3 was detected in 31 (67%) patients and 15 (33%) had a normal conducting AI 3. Monomorphic sustained VT was inducible in 16 (35%). Among patients with SCAI 3, 17 (55%), and 16 (52%), had an R’’ in V1, and NTP ≥80ms in aVF, respectively, compared to only 1 (7%), and 1 (7%) patients with normal conducting AIs. Of the 24 patients with an R’’ in V1 and/or NTP ≥80ms in aVF, 22 (92%) had a SCAI 3. In univariable analysis an R’’ in V1 had an odds ratio (OR) of 17.0 (p=0.010), a NTP ≥80ms in aVF had an OR of 14.9 (p=0.014), and QRS duration had an OR of 1.04 (per ms, p=0.030) in identifying SCAI 3. After correction for QRS duration, R’’ in V1 and NTP ≥80ms in aVF both remained independently predictive of SCAI 3 (OR 15.4, p=0.017, and OR 10.0, p=0.042, respectively). Combining R’’ in V1 and NTP ≥80ms in aVF into a diagnostic algorithm (Figure, B) yielded a sensitivity of 71% and specificity of 87% in detecting SCAI 3. In the validation cohort (n=34, age 44±14 years, 19 (56%) with SCAI 3 and 15 (44%) with normal conducting AI 3) the diagnostic algorithm had a sensitivity of 84% and specificity of 80% for a SCAI. Conclusion A diagnostic algorithm including R’’ in V1 and NTP ≥80ms in aVF had excellent sensitivity and specificity in detecting SCAI 3 in rTOF patients with RBBB in SR. These ECGs characteristics likely represent a delayed terminal RV activation directed towards the lateral RVOT caused by slow infundibular conduction. Whether this algorithm can contribute to non-invasive risk stratification for VT in a general rTOF population requires additional studies.Diagnostic algorithm to identify SCAI 3

A high-risk late gadolinium enhancement pattern is associated with arrhythmic events in patients with dilated cardiomyopathy

Abstract Introduction Myocardial fibrosis constitutes a substrate for the development of ventricular arrhythmias in patients with non-ischaemic dilated cardiomyopathy (DCM). Late gadolinium enhancement (LGE)-cardiac magnetic resonance (CMR) imaging represents a powerful tool for arrhythmic risk stratification. Moreover, arrhythmic risk is determined by the extent and localization of LGE. A high-risk LGE pattern, defined as the presence of epicardial, transmural or septal plus free-wall LGE, has been recently associated with a higher incidence of arrhythmic events comparing with other LGE patterns. Purpose To evaluate the prevalence of a high-risk LGE pattern in patients with DCM and its association with arrhythmic events. Methods From 2014 to 2021, all patients (N = 229) with DCM were prospectively evaluated in our tertiary care hospital. 174 patients underwent a 1.5 Tesla scanner CMR as part of the diagnostic workup and were included in the present study. The primary endpoint was a composite of sudden cardiac death or sustained monomorphic ventricular tachycardia. Results Mean age of our cohort was 61 years (standard deviation 14.5), and 64.2% were male. Median follow-up was 41 (interquartile range 26-62) months. LGE was present in 96 (55.2%) patients of our cohort (LGE+), and a high risk LGE pattern was found in 41 (42.7% of all LGE+ patients). LGE was more frequently located in the basal segments (78.6%). Mid-wall septal LGE was found in 46.9% of LGE+ patients, and it was the most common pattern. 21.4% of LGE+ patients had combined septal and free-wall LGE, 23.5% had epicardial LGE and 13.3% had transmural LGE. Baseline characteristics of LGE+ patients with and without a high-risk LGE pattern are shown at the Table. The incidence of ventricular arrhythmic events during follow-up was 31.7% in patients with a high-risk LGE pattern, and 9.1% in LGE+ patients but without a high-risk pattern (p=0.005). In patients without a high-risk LGE, including LGE- patients and LGE+ patients with other LGE patterns, incidence of ventricular arrhythmic events was 8.3% (p&amp;lt;0.001). The survival free curves for the combined arrhythmic endpoint comparing LGE+ patients with and without a high-risk pattern are shown in the Figure. Conclusion The presence of a high-risk LGE pattern in patients with DCM its associated with a higher incidence of ventricular arrhythmic events, comparing with LGE+ patients without a high-risk pattern. We suggest that this high-risk pattern should be taken into account when performing arrhythmic risk stratification in patients with DCM.TableFigure

Influence of standard modifiable risk factors on ventricular tachycardia after myocardial infarction

Abstract Background Sudden cardiac death due to ventricular tachyarrhythmia is the single greatest cause of death within two years after myocardial infarction (MI), especially early in the first 30 days. Purpose We aimed to assess the incidence of inducible ventricular tachycardia (VT) early after MI in those with standard modifiable risk factors (SMuRFs) versus those without. Methods Consecutive patients with LVEF ≤40% on day 3–5 after ST elevation myocardial infarction (STEMI) who underwent electrophysiology study were prospectively recruited. Positive EPS was defined as sustained monomorphic VT cycle length ≥200ms for &amp;gt; 10 seconds, or shorter duration if hemodynamic compromise occurred. The primary outcomes were inducibility of VT and all-cause mortality. Results A total of 410 patients, of which 126 had inducible VT on EPS, early after myocardial infarction were included. In our multiple regressions model, when smoking history was considered, ex-smokers were identified at increased risk of VT at EPS (adjusted OR 2.0, p=0.033) whilst those who never smoked or were current smokers had comparable risk. It also showed that the presence of any SMuRF apart from current smoker also conferred an increased risk of inducible VT (adjusted OR 1.9, p=0.043). For every 10 years increase in age the risk of death increased by a multiplicative factor of 1.3, for every 10% decrease in LVEF (%) the risk of death increased by a multiplicative factor of 1.9 and in patients with previous IHD, the risk of death was doubled. Neither the number of SMuRFs nor the presence of any SMuRF were associated with mortality. Conclusion In our cohort of patients with LVEF&amp;lt;40% early after STEMI who had an EPS to assess for inducible VT, either the presence of any of the three SMuRFs (hypertension, hypercholesterolemia or diabetes mellitus) or previous smoking doubled the chance of having VT induced. These data provide valuable information that could be integrated into clinical care protocols after myocardial infarction to improve long-term patient outcomes and further reinforces the need to modify SMuRFs in patients with ischemic heart disease.

Association of ventricular tachycardia morphology induced on electrophysiology study after myocardial infarction: long-term survival and ventricular tachyarrhythmia recurrence

Abstract Background Electrophysiology study (EPS) presents a valuable risk stratification tool to facilitate the implantation of implantable cardioverter-defibrillators (ICDs) to prevent sudden cardiac death from ventricular tachyarrhythmia early after myocardial infarction. Purpose To investigate long-term survival of patients with inducible ventricular tachycardia (VT) at electrophysiology study (EPS) early after ST elevation myocardial infarction (MI) and possible association with site of origin of the induced VT. Methods Consecutive patients with LVEF ≤40% on day 3–5 after MI who underwent EPS were prospectively recruited. Positive EPS was defined as sustained monomorphic VT cycle length ≥200ms for &amp;gt;10 seconds, or shorter duration if hemodynamic compromise occurred. The primary outcome was time to death from any cause. The secondary outcome was time to the composite endpoint of first activation of ICD for ventricular tachyarrhythmia or death. Results A total of 126 patients with inducible VT on EPS early after MI were included with median follow up 6.7 years. 54% had LBBB and 46% had RBBB morphologies during induced VT. The distributions of age, sex, left ventricle ejection fraction, cardiovascular risk factors, infarct artery and EPS characteristics did not differ significantly by induced VT morphology. The estimated risk of death was independently associated with RBBB morphology of VT induced at EPS (adjusted HR 3.2, 95%CI 1.0-10.0, p=0.044). The estimated risk of the composite end-point of spontaneous ventricular tachyarrhythmia recurrence or death was also independently associated with RBBB morphology of VT induced at EPS (HR 1.8, 95%CI 1.0-3.2, p=0.043). Conclusion There is an increased risk of death and spontaneous ventricular tachyarrhythmia recurrence at median follow up of 6.7 years, associated with RBBB morphology of VT (likely origin from left ventricle) induced at EPS early after MI, in those with LVEF &amp;lt;40%. This study is the first to characterise the association between site of origin of VT induced at EPS after myocardial infarction, indicated by RBBB or LBBB morphology, and overall survival as well as activation free survival. The results could help to identify a group of patients that could benefit from closer monitoring post MI and more intense preventative management to improve long-term outcomes.

Abstract 13716: Implanting an Extravascular ICD in Patients With a Prior Subcutaneous ICD

Background: The Extravascular Implantable Cardioverter Defibrillator (EV ICD) has been demonstrated as an effective therapy to treat sudden cardiac death using a substernal lead position. Limited data regarding the use of EV ICD in patients with prior subcutaneous ICD (S-ICD) is available. Methods: The EV ICD Pivotal study database was reviewed for subjects with a prior S-ICD. Procedure times were compared using the Wilcoxon rank-sum test. Results: Of the 316 subjects that had an implant attempt in the EV ICD Pivotal study, 9 subjects at 3 sites had history of a prior implanted S-ICD. All were male with a mean age of 59.6 ± 14.4 years. Mean Body Mass Index (BMI) was 29.5 ± 4.7. Five subjects had secondary prevention indication. Mean follow up duration was 1.4 ± 0.7 years. The study protocol required S-ICD explant prior to study enrollment. The mean time between S-ICD explant and EV ICD implant was 35 ± 19 days. Procedure times were similar to denovo EV ICD implant. Median times from first incision to final suture, inclusive of defibrillation testing, for subjects with and without prior S-ICD were 79 (IQR, 69 to 108) and 60.5 (IQR, 52 to 84.5) minutes, respectively (P=0.10). All subjects were defibrillated with 30 J or less at implant. There were no major intraprocedural complications and only 1 major complication during the follow up period, an implant site infection at 18 months. The Florida Patient Acceptance Survey, issued at 6 months post-implant, demonstrated high device acceptance rate with little or no body image concerns. Two subjects each had an appropriately treated episode of spontaneous sustained monomorphic VT, one terminated by ATP and the other terminated by shock following ATP. Conclusions: The EV ICD System can be successfully implanted in patients who previously had an S-ICD. History of S-ICD did not significantly increase procedure time. The EV ICD had a high acceptance in this subgroup and may provide advantage over S-ICD due to its smaller size, and ability to deliver ATP.

Influence of standard modifiable risk factors on ventricular tachycardia after myocardial infarction

BackgroundInducible ventricular tachycardia (VT) at electrophysiology study (EPS) predicts sudden cardiac death because of ventricular tachyarrhythmia, the single greatest cause of death within 2 years after myocardial infarction (MI).ObjectivesWe aimed to assess the association between standard modifiable risk factors (SMuRFs) and inducible VT at EPS early after MI.MethodsConsecutive patients with left ventricle ejection fraction ≤40% on days 3–5 after ST elevation MI (STEMI) who underwent EPS were prospectively recruited. Positive EPS was defined as induced sustained monomorphic VT cycle length ≥200 ms for ≥10 s or shorter if hemodynamically compromised. The primary outcome was inducibility of VT at EPS, and the secondary outcome was all-cause mortality on follow-up.ResultsIn 410 eligible patients undergoing EPS soon (median of 9 days) after STEMI, 126 had inducible VT. Ex-smokers experienced an increased risk of inducible VT [multivariable logistic regression adjusted odds ratio (OR) 2.0, p = 0.033] compared with current or never-smokers, with comparable risk. The presence of any SMuRFs apart from being a current smoker conferred an increased risk of inducible VT (adjusted OR 1.9, p = 0.043). Neither the number of SMuRFs nor the presence of any SMuRFs was associated with mortality at a median follow-up of 5.4 years.ConclusionsIn patients with recent STEMI and impaired left ventricular function, the presence of any SMuRFs, apart from being a current smoker, conferred an increased risk of inducible VT at EPS. These results highlight the need to modify SMuRFs in this high-risk subset of patients.