Diagnosis Of Ventricular Arrhythmias Research Articles

Exercise does not influence development of phenotype in PLN p.(Arg14del) cardiomyopathy.

Endurance and frequent exercise are associated with earlier onset of arrhythmogenic right ventricular cardiomyopathy (ARVC) and ventricular arrhythmias (VA) in desmosomal gene variant carriers. Individuals with the pathogenic c.40_42del; p.(Arg14del) variant in the PLN gene are frequently diagnosed with ARVC or dilated cardiomyopathy (DCM). The aim of this study was to evaluate the effect of exercise in PLN p.(Arg14del) carriers. In total, 207 adult PLN p.(Arg14del) carriers (39.1% male; mean age 53 ± 15years) were interviewed on their regular physical activity since the age of 10years. The association of exercise with diagnosis of ARVC, DCM, sustained VA and hospitalisation for heart failure (HF) was studied. Individuals participated in regular physical activities with amedian of 1661 metabolic equivalent of task (MET) hours per year (31.9MET-hours per week) until clinical presentation. The 50% most and least active individuals had asimilar frequency of sustained VA (18.3% vs 18.4%; p = 0.974) and hospitalisation for HF (9.6% vs 8.7%; p = 0.827). There was no relationship between exercise and survival free from (incident) sustained VA (p = 0.65), hospitalisation for HF (p = 0.81), diagnosis of ARVC (p = 0.67) or DCM (p = 0.39) during follow-up. In multivariate analyses, exercise was not associated with sustained VA or HF hospitalisation during follow-up in this relatively not-active cohort. There was no association between the amount of exercise and the susceptibility to develop ARVC, DCM, VA or HF in PLN p.(Arg14del) carriers. This suggested unaffected PLN p.(Arg14del) carriers can safely perform mild-moderate exercise, in contrast to desmosomal variant carriers and ARVC patients.

Outcomes After Development of Ventricular Arrhythmias in Single Ventricular Heart Disease Patients With Fontan Palliation.

With the advent of more intensive rhythm monitoring strategies, ventricular arrhythmias (VAs) are increasingly detected in Fontan patients. However, the prognostic implications of VA are poorly understood. We assessed the incidence of VA in Fontan patients and the implications on transplant-free survival. Medical records of Fontan patients seen at a single center between 2002 and 2019 were reviewed to identify post-Fontan VA (nonsustained ventricular tachycardia >4 beats or sustained >30 seconds). Patients with preFontan VA were excluded. Hemodynamically unstable VA was defined as malignant VA. The primary outcome was death and heart transplantation. Death with censoring at transplant was a secondary outcome. Of 431 Fontan patients, transplant-free survival was 82% at 15 years post-Fontan with 64 (15%) meeting primary outcome of either death (n=16, 3.7%), at a median 4.6 (0.4-10.2) years post-Fontan, or transplant (n=48, 11%), at a median of 11.1 (5.9-16.2) years post-Fontan. Forty-eight (11%) patients were diagnosed with VA (90% nonsustained ventricular tachycardia, 10% sustained ventricular tachycardia). Malignant VA (n=9, 2.0%) was associated with younger age, worse systolic function, and valvular regurgitation. Risk for VA increased with time from Fontan, 2.4% at 10 years to 19% at 20 years. History of Stage 1 surgery with right ventricular to pulmonary artery conduit and older age at Fontan were significant risk factors for VA. VA was strongly associated with an increased risk of transplant or death (HR, 9.2 [95% CI, 4.5-18.7]; P<0.001), with a transplant-free survival of 48% at 5-year post-VA diagnosis. Ventricular arrhythmias occurred in 11% of Fontan patients and was highly associated with transplant or death, with a transplant-free survival of <50% at 5-year post-VA diagnosis. Risk factors for VA included older age at Fontan and history of right ventricular to pulmonary artery conduit. A diagnosis of VA in Fontan patients should prompt increased clinical surveillance.

PO-04-222 OUTFLOW TRACT VERSUS NON-OUTFLOW TRACT VENTRICULAR ARRHYTHMIAS IN ATHLETES: MYOCARDIAL SUBSTRATE AND LONG-TERM CLINICAL OUTCOMES

Outflow tract ventricular arrhythmias (OT-VA) are common in healthy subjects without structural heart disease (SHD), and are generally considered benign. However, athlete-specific data on the clinical meaning of different ventricular arrhythmia (VA) morphologies are scarce. To assess the prevalence of SHD as well as long-term clinical and sports medicine outcomes in a cohort of athletes with OT-VA undergoing a comprehensive diagnostic assessment, by comparing them with athletes with non-outflow tract VAs (nOT-VA). We conducted a multi-center, observational, retrospective study enrolling athletes who were referred because of complex VAs (>500 PVCs/24 h, exercise-induced VAs, nonsustained or sustained ventricular tachycardia). Athletes were categorized into two groups: OT-VA, in case of monomorphic ventricular arrhythmias of left bundle branch block and inferior axis morphology; nOT-VA, in case of polymorphic VAs or monomorphic VAs of right bundle branch block or left bundle branch block and superior/intermediate axis. The two co-primary outcomes were survival free from all-cause death or sustained VAs and sports practice at last follow-up. 175 athletes with complex ventricular arrhythmias (OT-VA,n=82; nOT-VA,n=93) were included in the present analysis; clinical characteristics are resumed in the Table. Remarkably, the prevalence of signs of SHD was higher in nOT-VA compared to OT-VA (Table). A final diagnosis of idiopathic VA was more common in OT-VA compared to nOT-VA and, accordingly, catheter ablation was more commonly performed in the former group. Over a median follow-up of 61(43-85) months, there were 2 cardiac arrests and 1 appropriate ICD shock, all occurring in athletes in the nOT-VA group with in vivo evidence of SHD and polymorphic VAs, for an overall prevalence of a primary outcome event of 0 and 3% in the OT-VA and the nOT-VA groups, respectively (p=0.25). At last follow-up, 31 athletes (18%) practiced competitive sports (OT-VA vs. nOT-VA,p=0.23), while 92 (53%) were leisure-time athletes (OT-VA vs. nOT-VA,p=0.91). Our data confirm that the prevalence of an underlying SHD substrate is lower in athletes with OT-VA than in athletes with nOT-VA, and that all major adverse cardiac events occurred in athletes with polymorphic VAs. Nevertheless, a comprehensive workup with liberal use of cardiac magnetic resonance allowed the identification of SHD in a substantial minority of athletes with OT-VA, with clear implications for sports eligibility assessment.

Impact of ventricular arrhythmia on LVAD implantation admission outcomes

Ventricular arrhythmias (VAs) are common after left ventricular assist device (LVAD) implantation though data are mixed on whether these events have an impact on mortality. The National Inpatient Sample (NIS) database from 2002-2019 was queried for LVAD implantation admissions. Secondary ICD codes were analyzed to assess for the occurrence of VAs during this admission. Propensity score matching (PSM) was used to control for confounding variables between those with versus without VAs. The NIS database from 2002-2019 contained 43 936 admissions with LVAD implantation. VAs occurred in 19 985 (45.4%) patients. After PSM, the study cohort consisted of 39 989 patients, 19 985 (50.0%) of which had a secondary diagnosis of VA during the admission. When compared to those without VA, those with VA were at no higher risk for in-hospital mortality (adjusted odds ratio 1.011, 99.9% CI 0.956-1.069, p=0.699). Those with a VA were at higher risk for cardiogenic shock and requiring mechanical ventilation, tracheostomy, and percutaneous endoscopic gastrostomy placement. Patients with a VA were also at lower risk for device thrombosis. Conversely, the VA group was at no higher risk for stroke. In comparing trends from 2002 to 2019, the incidence of VAs has increased, while the mortality rate of those with and without VAs has decreased during this same period. In this retrospective study of the NIS database, VAs were common (45.4%) during the LVAD implantation admission. However, the occurrence of VAs during the implantation admission did not alter in-hospital mortality. More longitudinal studies are required to assess the long-term impact of VAs on mortality. In comparing trends from 2002-2019, the incidence of VAs has increased, while the mortality rate of those with and without VAs has decreased.

Arrhythmogenic Right Ventricular Cardiomyopathy Prevalence and Arrhythmic Outcomes in At-Risk Family Members: A Systematic Review and Meta-Analysis.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a complex cardiomyopathy with autosomal dominant inheritance and age-related incomplete penetrance, characterized by a high risk of sudden cardiac death. Recent professional consensus guidelines recommend clinical cardiac lifelong serial screening for at-risk family members refined only by age, but family genotype might influence necessary screening. Although numerous studies report prevalence of disease and arrhythmia in family members and explore predictors of penetrance and arrhythmic risk, a systematic review consolidating this evidence is lacking. We searched Medline (PubMed), Embase, The Cochrane Library, and Web of Science for studies that reported prevalence of (1) diagnosis of ARVC per 2010 Task Force Criteria and/or (2) sustained ventricular arrhythmias (VA) in at least 10 family members of definite patients with ARVC. We identified 41 studies, including 36 that reported diagnosis by Task Force Criteria and 22 VA. Meta-analysis of 1359 family members, from 13 unique cohorts showed an average prevalence estimate of 25% for diagnosis as per Task Force Criteria (95% CI, 0.15-0.35, I2=96.44%). Overall prevalence of VA among gene-positive family members was 18% (95% CI, 0.13-0.23, I2=33.25%) in 7 independent studies (n=597). Family genotype was a significant risk factor for diagnosis of both ARVC (odds ratio, 6.91 [95% CI, 1.27-37.70]; P=0.0005) and VA (odds ratio, 13.62 [95% CI, 0.91-204.13]; P=0.06). Male gender was not associated with disease prevalence (odds ratio, 1.18 [95% CI, 0.72-1.95]; P=0.42) or VA (odds ratio, 0.81 [95% CI, 0.51-1.29]; P=0.91). The prevalence of ARVC and VA in at-risk family members differs significantly based on family genotype. Although recent recommendations provide a guideline based only on age, we propose screening every 1 to 2 years for gene-positive family members and every 3 to 5 years for first-degree relatives of gene-elusive cases, as long as they are asymptomatic and not athletes.

Prognostic Significance of Ventricular Arrhythmias in 13444 Patients With Acute Coronary Syndrome: A Retrospective Cohort Study Based on Routine Clinical Data (NIHR Health Informatics Collaborative VA-ACS Study).

BackgroundA minority of acute coronary syndrome (ACS) cases are associated with ventricular arrhythmias (VA) and/or cardiac arrest (CA). We investigated the effect of VA/CA at the time of ACS on long‐term outcomes.Methods and ResultsWe analyzed routine clinical data from 5 National Health Service trusts in the United Kingdom, collected between 2010 and 2017 by the National Institute for Health Research Health Informatics Collaborative. A total of 13 444 patients with ACS, 376 (2.8%) of whom had concurrent VA, survived to hospital discharge and were followed up for a median of 3.42 years. Patients with VA or CA at index presentation had significantly increased risks of subsequent VA during follow‐up (VA group: adjusted hazard ratio [HR], 4.15 [95% CI, 2.42–7.09]; CA group: adjusted HR, 2.60 [95% CI, 1.23–5.48]). Patients who suffered a CA in the context of ACS and survived to discharge also had a 36% increase in long‐term mortality (adjusted HR, 1.36 [95% CI, 1.04–1.78]), although the concurrent diagnosis of VA alone during ACS did not affect all‐cause mortality (adjusted HR, 1.03 [95% CI, 0.80–1.33]).ConclusionsPatients who develop VA or CA during ACS who survive to discharge have increased risks of subsequent VA, whereas those who have CA during ACS also have an increase in long‐term mortality. These individuals may represent a subgroup at greater risk of subsequent arrhythmic events as a result of intrinsically lower thresholds for developing VA.

Abstract 13823: Clinical Presentation Rather Than Imaging Findings Determine Outcomes in Cardiac Sarcoidosis

Background: Cardiac PET and MRI have facilitated increased diagnosis of Cardiac Sarcoidosis (CS). Varied clinical presentations such as advanced heart block, ventricular arrhythmias and heart failure (HF) are initiating this diagnostic pathway but it is unclear if prognosis is dictated by clinical presentation or imaging findings. In our quaternary care center, we conducted a retrospective review of patients diagnosed with CS by cardiac MRI/PET and examined outcomes in relation to imaging findings and clinical presentation. Methods: 223 patients underwent evaluation for suspected CS by cardiac MRI/PET between 2016-2019 and 62 were identified as having CS based on clinical and imaging criteria. We divided this cohort based on their primary clinical indication for imaging- arrhythmia, HF or screening due to history of pulmonary sarcoidosis. Outcome defined as MACE included death, ICD-shock or admission for HF. Results: Study population was predominantly male (65%), Caucasian (79%) with mean age 60±10 years, Referral diagnosis was HF in 37 (59%), arrhythmia (defined as high grade AV block/ventricular arrhythmias) in 15 (25%) and screening in 10 (16%). While there were no differences in the CMRI LGE findings or degree of inflammation by FDG-PET, there was a higher incidence of resting anteroseptal perfusion on PET, with a higher summed rest score in the arrhythmia group (mean 2 vs 0 in other groups; p&lt;0.05). Based on imaging findings, 39% were treated with steroids, 25% with immunosuppressant, 10% were on combination. Over mean follow-up of 3.5 years, there were 26 events- 6 deaths, 10 ICD shocks 10 heart failure admissions. Event-free survival was 53%, 76% and 80% in the arrhythmia, HF and screening groups respectively. In multivariable analysis, a model that included VT presentation (OR 11; p&lt;0.05) and global hypokinesis on PET images (OR 10; p&lt;0.05) had a sensitivity of 86% and specificity of 63% for MACE prediction. Compared to the model, neither Inflammation on FDG-PET or LGE (MRI) predicted outcomes and treatment with steroids and/or immunosuppressant did not alter prognosis. Conclusions: In this single center study of CS, a primary diagnosis of ventricular arrhythmia and global LV systolic dysfunction, regardless of LVEF, had the worst prognosis.

Cardiac magnetic resonance features of left dominant arrhythmogenic cardiomyopathy: differential diagnosis with myocarditis

Cardiac magnetic resonance (CMR) findings suggesting a suspected left-dominant arrhythmogenic cardiomyopathy (LDAC) may be difficult to distinguish from those related to previous myocarditis; however, especially in patients with ventricular arrhythmias (VA) with ECG morphology consistent with a left ventricle (LV) origin differential diagnosis is fundamental. Aim of the study was to identify potential imaging features at CMR specific for LDAC diagnosis. Between January 2011 and December 2019, we enrolled 15 consecutive stable patients with a recent diagnosis of significant VA and ECG morphology consistent with a LV origin, detection of potential LV arrhythmic substrate at CMR and undergoing a clinically-indicated LV endomyocardial biopsy showing tissue abnormalities consistent with the diagnosis of LDAC. From the same CMR-endomyocardial biopsy registry, a second group of 30 consecutive patients who underwent CMR and biopsy with a histological diagnosis of previous myocarditis were identified. (1) Subepicardial LGE at the level of the posterolateral wall of the LV was detected in 13 cases of LDAC vs. 21 cases of myocarditis; (2) fat infiltration, and particularly subepicardial posterolateral fat infiltration, was found in almost all LDAC patients vs. one myocarditis only (p < 0.01). (3) No differences in other CMR findings or in any clinical or echocardiographic parameters were found between patients with a biopsy consistent with LDAC vs. myocarditis. In patients with significant VA and ECG morphology consistent with a LV origin, the presence of morpho-functional involvement of the subepicardial layer of LV posterolateral wall at CMR (LGE, fat infiltration, wall dyskinesis) supports LDAC diagnosis.

Computer Aided Diagnosis of Ventricular Arrhythmias from Electrocardiogram Lead II Signals

Computer Aided Diagnosis of Ventricular Arrhythmias from Electrocardiogram Lead II Signals

Human machine interfacing technique for diagnosis of ventricular arrhythmia using supervisory machine learning algorithms

SummaryThe state of art to integrate bio‐signals with computer based diagnosis is taking dominance. The man‐machine interface is useful for early and immediate clinical interpretation. The electrocardiogram (ECG) signal plays a vital role in revealing the possible data towards categorizing normal and abnormal cardiac functioning. The fatal conditions exhibited by ventricular arrhythmias (VA) pose a remarkable change in the feature set of the ECG signals. In this work, a novel approach to segregate the superior feature toward the ventricular arrhythmias are extracted using feature ranking score algorithm (FRSA). The FRSA collects feature vectors in three different domains and ranks it to find out the more prevalent feature for diagnosis of VA. The Support Vector Machine (SVM) classifier is administered by supervisory machine learning optimization algorithm Mean Grey Wolf Optimization (MGWO). The performance estimates of SVM‐MGWO is compared for classification of VA signals with other optimization also like SVM‐Particle Swarm Optimization (SVM‐PSO) and SVM‐Grey Wolf Optimization (SVM‐GWO). The non‐parametric and parametric analysis evidently shows the improved performance of feature parameter estimates for classification. The accuracy of classification for SVM‐MGWO attains 100% for finding test data with VA at a minimal convergence iteration while comparing it with the other mentioned supervisory algorithms. The standard deviation during parametric analysis is negligible, which reveals the fact that reductant feature extracted and utilized for testing of ECG data is minimal. The performance estimates attained by the proposed algorithm shows the selection of optimal feature for the findings of VA through ECG. The man‐machine interface aides in the early diagnosis of ventricular arrhythmias using non‐invasive diagnosing tool, the ECG.

Ventrikuläre Herzrhythmusstörungen

Ventricular arrhythmias include awide range of potentially benign single ventricular premature contractions to ventricular tachycardia and ventricular fibrillation with arisk for sudden cardiac death. The diagnosis of ventricular arrhythmia is made by 12-lead electrocardiogram, 24 h Holter monitoring, an external or implantable loop recorder, or during in-hospital monitoring. Especially the diagnosis of wide complex tachycardias is challenging in terms of differentiating between ventricular tachycardia and supraventricular tachycardia with aberrant atrioventricular conduction. After documentation of ventricular arrhythmias, diagnostic work-up with respect to structural or electrical cardiomyopathy is mandatory followed by risk stratification for sudden cardiac death. Therapeutic options for treatment of ventricular arrhythmias range from pharmacological therapy and interventional procedures such as catheter ablation and implantable devices. The current article provides an overview of the diagnosis of ventricular tachycardia and underlying cardiomyopathies. Furthermore, medical and interventional therapies are described. In addition, the indications for implantable and wearable defibrillators are presented.

ALGORITHM THE MANAGEMENT OF PATIENTS WITH STABLE CORONARY ARTERY DISEASE AND VENTRICULAR ARRHYTHMIAS

The paper proposes the algorithm for the management of patients with stable coronary artery disease, preserved left ventricular ejection fraction and ventricular arrhythmias. Particular clinical case with the definition of arrhythmias nature is discussed in the algorithm based on international and national guidelines. In the algorithm underlined the importance to the involvement of autonomic regulation in the arrhythmogenesis, of topical diagnosis of ventricular arrhythmias and existence of anexity or distress. The key points of suggested algorithm is improve quality of life of the patient and the prevention of sudden cardiac death.

ACURACY OF TOPICAL DIAGNOSIS OF VENTRICULAR ECTOPIC ARRHYTHMIAS USING NON-INVASIVE MAPPING

Purpose. The aim of the study was to compare the accuracy of non-invasive topical diagnosis of ventricular arrhythmias and the data of intracardiac mapping. Materials and methods. Thirty-six patients (16 male and 20 female) 44.2±7.6 years of age having ventricular ectopic arrhythmias were included in retrospective study. Patient selection was based on the results of intracardiac mapping in such a way to form six equal groups by six patients in each. Before the ablation procedure, non-invasive mapping was performed in all patients. After the procedure, the accuracy of non-invasive mapping was evaluated in comparison with invasive procedure results. Results. Non-invasive mapping allows to localize the ectopic foci in the same anatomical zone with successful ablation site in 24 (67 %) of cases (p=0.0001 in comparison with invasive mapping). The correct localization of the ectopic foci using traditional topical diagnosis algorithm was possible in 23 (64 %) of cases (p=0.0001 in comparison with invasive mapping and p=0.805 in comparison with non-invasive mapping). Statistically insignificant bias of greater accuracy of non-invasive mapping in case of outflow tract location of the ectopic foci was registered. Conclusion. The accuracy of non-invasive mapping varies from 50 to 83 % depending on ectopic focus location (mean 67 %) that is comparable with traditional electrocardiographic topical diagnosis algorithm accuracy.

Abstract 13544: Differences in the Population of Muscular Dystrophy Patients With Respect to Ventricular Tachycardia, Heart Failure and Use of Implantable Cardioverters Defibrillators

Introduction: As the treatment of the respiratory and skeletal muscle complications associated with muscular dystrophy (MD) has improved, males with MD are living longer and are more likely to develop cardiac disease. The impact of sudden cardiac death related to ventricular arrhythmias and heart failure and the indications for ICD implantation are not well established. Hypothesis: We evaluated the hypothesis that VT is a significant contributor to mortality in hospitalized patients with MD and this is improved with ICD implantation. Methods: We searched the Pediatric Health Information System (PHIS) database for males with discharge diagnosis codes of MD and different combinations of heart failure (HF), ventricular arrhythmias (VT) and ICD placement between 2003 and 2013. Results: There were significant differences in the mean length of stay and mean age between MD patients with HF and/or VT versus all hospitalized male MD patients (p&lt;0.05). Out of a total of 76 deaths in MD patients, 32% (n=24) were related to HF. Of those, 30% (n=7) also had a diagnosis of VT. Isolated VT without HF was only 1% (n=42) of admissions and the cause of death in 2 patients. However, ICD’s were implanted in 12% (n=5) of MD/VT patients compared to 5% (n=5) of MD/HF/VT patients. No deaths were seen in patients with ICD’s. Only 1 ICD was placed prior to 2009. Conclusions: VT was a frequent cause of death in hospitalized male patients with MD and HF, however isolated VT without HF was not. No deaths were found in the small number of patients with ICD’s. Further prospective studies are needed to validate the importance of ICD use in MD patients

Omega-3 index of erythrocytes and predictors of sudden cardiac death in patients with coronary heart disease and ventricular arrhythmias

Aim.To assess the association between ω-3 index of erythrocytes and demographic, electrophysiological, and echocardiographic (EchoCG) predictors of sudden cardiac death (SCD) in patients with coronary heart disease (CHD) and ventricular arrhythmias (VA).Material and methods.The study included 25 patients with a verified diagnosis of CHD and VA. Gas chromatography method was used to measure the content (%) of eicosapentaenoic (EPA) and docosahexaenoic (DHA) polyunsaturated fatty acids (PUFA) in peripheral blood erythrocytes, with the calculation of a summary (EPA + DHA) ω-3 index. All participants underwent 24-hour electrocardiography (ECG) monitoring, with the assessment of maximal, minimal, and mean heart rate (HR), heart rate variability (HRV) parameters (SDNN and pNN50), heart rate turbulence (TO and TS), microvolt T wave alternans (mTWA), and the number of ventricular extrasystoles (VE) and transient and persistent ventricular tachycardia (VT) episodes. All patients also underwent EchoCG.Results.In examined patients, the values of ω-3 index of erythrocytes varied from 1,12% to 6,4% (mean 3,74%, 95% CI 2,02-4,38%). There was a weak correlation between ω-3 index or EPA levels (%) and the HRV parameter of pNN50. In addition, ω-3 index or DHA levels (%) negatively correlated with the daily VE number. The 5:00 AM value of mTWA (II lead, update factor 1/8) weakly correlated withω-3 index and DHA levels. There was a moderate positive correlation between E/A ratio and omega-3 index, or EPA and DHA levels.Conclusion.Patients with CHD and VA were characterised by low ω-3 index values and high (56%) or moderate (44%) levels of cardiovascular risk. The values of ω-3 index positively correlated with the daily VE number and negatively correlated with E/A ratio and pNN50 parameter of HRV.

Cardiomyopathy in Boxer dogs: A retrospective study of the clinical presentation, diagnostic findings and survival

Objectives To retrospectively compare and contrast the clinical presentation, diagnostic findings and survival in Boxer dogs with cardiomyopathy, with or without left ventricular (LV) systolic failure. Animals, materials and methods Medical records of Boxers referred between 1993 and 2008 in which a diagnosis of ventricular arrhythmias and/or cardiomyopathy was made, were reviewed. Dogs were divided into two groups according to their left ventricular (LV) systolic diameter, group A normal (20 dogs) or group B dilated (59 dogs). Results Dogs in group A had a better outcome than dogs in group B (median survival time of 124 and 17 weeks respectively, p < 0.001). In group B, dogs with a history of collapse had a worse outcome (median survival time of 10 weeks) compared with dogs not showing collapse (median survival time 24 weeks) ( p = 0.031). Conclusions The majority of dogs, in this UK study, presented with the myocardial dysfunction form of the disease, with LV dilation and congestive heart failure signs. The prognosis was worse in dogs with LV dilation compared to dogs with a normal LV and ventricular arrhythmias. In the Boxers with LV dilation, dogs with collapse had a worse prognosis than those without.

Computerized Methods of Pace‐Mapping for Topical Diagnosis of Ventricular Arrhythmias

Surgical treatment of ventricular arrhythmias (VAs) is an effective method of solving sudden cardiac death. The important problem of surgical treatment of VAs is the topical diagnosis of the origin of arrhythmia. The precise localization of this area is extremely important for effectiveness of operation. The method of epicardial mapping of the heart during the induced paroxysm of VA is widely used for solving this problem. This problem is difficult when it is impossible to induce tachycardia during the operation. The method of pace-mapping was developed for such cases. This method includes sequential electrical stimulation of ventricles with ECG recording and comparison between intraoperative and preoperative ECG. The goal is the identification of the area of ventricles closed to preoperative ECG with VA. Manual processing of these data is difficult and takes time. The results of such processing have a low precision. That is why we propose using computerized methods. The goal of this investigation is to develop computerized methods of topical ECG diagnosis of VA. We propose a method of computer comparative analysis of ECG morphology for spontaneous and stimulated ECG. The goal is the determination with stimulated ECG the point of ventricles with ECG closest to spontaneous ECG during ventricular tachycardia. Nine patients (15-57 years old) with VA were studied. The main result of this investigation is that computerized pace-mapping method is an effective tool for topical diagnostics of different forms of VAs, which is impossible to induce by electrical programmed stimulation.

Clinical application of arrhythmia analyzer in ICU.

A microcomputer system (NEC Sanei Ins. Company Ltd.) has been developed for the continuous monitoring and storage and retrieval of data from serial ECG tracings in each ICU patient. Eight hundred and forty patients were monitored using the system. Diagnosis of ventricular arrhythmias and ST-segment change was highly accurate. However, the false positive diagnosis was sometimes generated by artifact. Diagnosis of supraventricular arrhythmias or rhythmic abnormalities were less accurate compared with that of ventricular arrhythmias. Application of microcomputer system in the space limited ICU is of benefit to identify and evaluate ECG gracings in time saving way. However, further version-up is needed to promote the accuracy of the diagnosis.