QRS Amplitude Research Articles

Abstract 13290: Childhood-Onset Arrhythmogenic Cardiomyopathy Associated With Genetic Variants in Desmoplakin

Introduction: Arrhythmogenic cardiomyopathy (ACM) resulting from variants in the desmosomal gene desmoplakin (DSP) is typically an adult onset disorder. Here, we describe penetrance, expression and outcomes of DSP-associated ACM in children. Methods: Patients aged ≤21 years with pathogenic/likely pathogenic variants in DSP were included. Penetrance was defined by:(i) ECG: T-wave inversion V4-V6; mean QRS amplitude <0.5mV in limb leads.(ii) Arrhythmia: >500 VPBs/24 hours, non-sustained or sustained ventricular arrhythmia (VA)(iii) LV dysfunction (EF<50%)(iv) Sub-epicardial late gadolinium enhancement (LGE). The cardiac phenotype was defined as primarily RV, isolated LV (left dominant) or biventricular. Myocardial inflammation was defined as chest pain with elevated troponin ± ST segment changes. A composite primary outcome was sustained VA, death or transplant. Results: We identified 24 patients (67% female) inclusive of 8 probands and 16 family members. Variants were truncating in 22 and missense in 2; a second variant occurred in 4. Presenting symptoms were cardiac arrest (1); myocardial inflammation (3) with cardiac arrest (1), sustained VA (1), dyspnea (2), syncope (1), palpitations (1). ACM was penetrant in 17 (71%), with expression first evident at 15.2±3.3 years. The cardiac phenotype was left dominant (12) and biventricular (5). Isolated RV disease was not seen. Penetrant features were:(i) ECG: transient T-wave inversion in 1 (6%) and QRS amplitude <0.5mV in 6 (35%). (ii) Arrhythmia in 14 (82%) evident at presentation in 13 (92%) and an isolated finding in 2. (iii) LV dysfunction in 10 (59%; EF 35 ± 12%) evident at presentation in 9. (iv) Sub-epicardial LGE in 13 (76%) evident at presentation in 12 (92%) and an isolated finding in 2. Over 3.4±3.2 years, 6 (35%; 4 probands and 2 family members) reached the primary outcome; sustained VA at presentation (3), sustained VA (2), transplant (1). Myocardial inflammation occurred in 5 (21%), 2 of whom reached the primary outcome but this was not significant (p=0.79). Conclusions: DSP-mediated ACM may be fully penetrant in children affecting both probands and family members. VA and subepicardial LGE are prominent early features of disease and pediatric surveillance should reflect these findings.

Abstract 10353: Independent Validation of the Ecg Risk Score for Sudden Death Risk Stratification in Pediatric Hypertrophic Cardiomyopathy

Background: Hypertrophic cardiomyopathy (HCM) is the leading cause of sudden cardiac death (SCD) in children and young adults. An ECG risk score tested in a Swedish cohort of 155 children with HCM had 97% sensitivity, 80% specificity, 45% positive predictive value (PPV), and 99% negative predictive value (NPV) for SCD risk prediction. Our goal was to validate the ECG risk score in an independent HCM cohort. Methods: Phenotype-positive pediatric HCM patients seen at a single center between 1987-2019 with at least 5 years follow-up from diagnosis, or a SCD event within 5 years of diagnosis, were retrospectively identified. First-evaluation ECGs were analyzed by a single operator blinded to patient outcomes. ECG risk score was calculated using QRS electrical axis, amplitude, duration, ST/T-wave abnormalities and QTc duration. The primary outcome was a composite of SCD, aborted sudden cardiac arrest, and appropriate shock from a prophylactic ICD. Results: Of 144 eligible patients with a median follow-up 14.6 yrs, 22 experienced SCD events within five years from diagnosis at a median age 12.1 yrs. The ECG risk score in patients experiencing a SCD event was 2-fold higher i.e. 8 (IQR 7-10) compared to the remaining cohort i.e. 4 (IQR 2-8) (p<0.001). An ECG risk score >5 had a sensitivity of 95% (CI 77%-100%), specificity 56% (46%-65%), PPV 28% (24%-33%), NPV 99% (91%-100%), and a receiver operating characteristic area under the curve of 0.76 for its ability to discriminate between patients with and without SCD events ( Figure 1 ). Compared to the discovery cohort, the score had strong sensitivity and NPV, but lower specificity and PPV. Conclusions: The ECG risk score for SCD risk stratification performed well in an independent Canadian validation cohort but overestimated SCD risk. Futher analysis will determine if inclusion of the ECG risk score can enhance the performance of currently available SCD risk prediction models for pediatric HCM.

Role of QRS amplitude, fractionation and duration in predicting clinical response to anti-inflammatory treatment in cardiac sarcoidosis

Abstract Background Low QRS amplitude (QRSa), QRS fractionation (QRSf) and longer QRS duration (QRSd) are markers of myocardial fibrosis and inflammation in non-ischemic cardiomyopathy (NICM). Objective To determine if reduction of inflammation with treatment of cardiac sarcoidosis (CS) may reverse these 12 lead ECG parameter changes. Methods 21 patients (pts) with CS and VT ablation with a positive baseline positron emission tomographic (PET 1) scan were studied. All pts received prednisone ≥40 mg for 4 to 8 weeks followed by a taper and maintenance with methotrexate ± low-dose prednisone, <10 mg/day, until clinically stable and resolution of inflammation on PET 2 one year after initial. In addition, pts with low LV ejection fraction (13/21) received guideline directed medical therapy for heart failure. Pts at 1yr with positive PET2 (9) were compared to those with negative PET2 (12). Baseline and 1yr 12-lead ECGs were analyzed for QRSd, ≥2QRSf contiguous leads and QRSa in the limb leads. Results Pts in PET2(+) vs PET2(−) groups has similar gender (men 89% vs 100%, p=0.42), age (57±8 vs 56±10 years, p=0.8) and LV ejection fraction (41±11 vs 46±11, p=0.31). Baseline 12-lead ECGs showed similar QRSd, ≥2QRSf contiguous leads and QRSa for PET2(+) vs PET2(−); P all >0.15 (Table 1). At 1 yr there was a lower prevalence of ≥2QRSf contiguous leads and strong trend for shorter QRS duration and larger QRSa in lead DI if PET2(−) vs PET2(+). 4 pts demonstrated loss of QRSf 2 contiguous leads and/or increase in QRSa in DI by at least 0.15 mV from baseline if PET2(−) and none if PET2(+). Conclusions In pts with CS and VT, reversal of inflammation may result in a greater QRSa and reduction in QRSf. An increase in QRSa in lead 1 by >0.15mV and/or loss of QRSf identifies a clear positive response to treatment and negative PET at 1 year. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): Richard T and Angela Clark Innovation Fund in Cardiovascular Medicine, the Mark S Marchlinski EP Research and Education Fund and the Winkelman Family Fund in Cardiovascular Innovation. Table 1

Diagnostic value of electrocardiograms to identify pericardial effusion in acute malaria: a cross-sectional study

Abstract Background Patients with acute malaria are at risk of pericarditis and may benefit from timely identification of pericardial effusion. However, diagnostic imaging tools, such as echocardiography, are not always available in malaria endemic regions. Purpose The aim of this study is to examine the diagnostic yield of pathology in electrocardiograms (ECG) to identify pericardial effusion in acute malaria. Methods We enrolled adult acute malaria patients in community healthcare clinics in a remote area in South America. All patients underwent ECG, echocardiography, and peripheral blood smears. We excluded patients on anti-malarial medication, suspected concomitant infection and pregnant women. All ECGs were examined for the following criteria: (i) PR-depression >0.5mm and/or ST-elevation 0.5–1mm (I, II, aVL, aVF, V2–6) (ii) PR-elevation >0.5mm (only aVR), (iii) ST/T-ratio >0.25 (only V6), (v) low voltage, defined as QRS amplitude <5 mm in limb leads or <10 mm in precordial leads, and (vi) Spodick's sign (all leads). A criterion was positive when present in ≥2 leads. Information on shortness of breath and/or chest pain was also collected. Pericardial effusion was diagnosed by echocardiography and had to be ≥0.5cm in width. Results We included 99 non-severe malaria patients (age 40±15 years, 55% men, median parasite density 1517/mm3, [interquartile range 528 to 6,585/mm3]) who suffered from Plasmodium vivax (n=75), falciparum (n=22 falciparum) and mixed vivax/falciparum (n=2). The ECGs showed a mean frequency of 78±16bpm, PR-interval 147±20ms, QRS 88±11ms and QT-interval 376±34ms. A total of 11 patients displayed pericardial effusion (mean width 0.9±0.3cm, n=7 vivax, n=2 falciparum, n=2 mixed). Patients with effusion were older (mean age 39 vs 53 years, P=0.003), but displayed no difference in sex, parasite density or parasite species compared to patients without pericardial effusion (P>0.05). Distribution of ECG findings and symptoms are displayed in figure 1A. PR-depression had a sensitivity and specificity for diagnosing pericardial effusion of 73% and 90%, respectively. The sensitivity and specificity for other ECG findings and clinical symptoms are displayed in Figure 1B. Conclusion ECG findings may aid in identifying pericardial effusion in acute malaria, specifically PR depression which had a diagnostic yield of 73% sensitivity and 90% specificity. Based on this, ECG in acute malaria may improve treatment and risk stratification when echocardiography is not an option. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): Novo Nordisk Foundation, Independent Research Fund Denmark ECG findings in malaria patients

Clinical validation and evaluation of a novel six-lead handheld electrocardiogram recorder compared to the 12-lead electrocardiogram in unselected cardiology patients (EVALECG Cardio).

Handheld electrocardiogram (ECG) monitors are increasingly used by both healthcare workers and patients to diagnose cardiac arrhythmias. There is a lack of studies validating the use of handheld devices against the standard 12-lead ECG. The Kardia 6L is a novel handheld ECG monitor which can produce a 6-lead ECG. In this study, we compare the 6L ECG against the 12-lead ECG. A prospective study consisting of unselected cardiac inpatients and outpatients at Leeds Teaching Hospital NHS Trust. All participants had a 12- and 6-lead ECGs. All ECG parameters were analysed by using a standard method template for consistency between independent observers. Electrocardiograms from the recorders were compared by the following statistical methods: linear regression, Bland-Altman, receiver operator curve, and kappa analysis. There were 1015 patients recruited. The mean differences between recorders were small for PR, QRS, cardiac axis, with receiver operator analysis area under the curve (AUC) of >80%. Mean differences for QT and QTc (between recorders) were also small, with AUCs for QT leads of >75% and AUCs for QTc leads of >60%. Key findings from Bland-Altman analysis demonstrate overall an acceptable agreement with few outliers instances (<6%, Bland-Altman analysis). Several parameters recorded by the Kardia 6L (QT interval in all six leads, rhythm detection, PR interval, QRS duration, and cardiac axis) perform closely to the gold standard 12-lead ECG. However, that consistency weakens for left ventricular hypertrophy, QRS amplitudes (Lead I and AVL), and ischaemic changes.

Automatic wide complex tachycardia differentiation using mathematically synthesized vectorcardiogram signals.

BackgroundAutomated wide complex tachycardia (WCT) differentiation into ventricular tachycardia (VT) and supraventricular wide complex tachycardia (SWCT) may be accomplished using novel calculations that quantify the extent of mean electrical vector changes between the WCT and baseline electrocardiogram (ECG). At present, it is unknown whether quantifying mean electrical vector changes within three orthogonal vectorcardiogram (VCG) leads (X, Y, and Z leads) can improve automated VT and SWCT classification.MethodsA derivation cohort of paired WCT and baseline ECGs was used to derive five logistic regression models: (i) one novel WCT differentiation model (i.e., VCG Model), (ii) three previously developed WCT differentiation models (i.e., WCT Formula, VT Prediction Model, and WCT Formula II), and (iii) one “all‐inclusive” model (i.e., Hybrid Model). A separate validation cohort of paired WCT and baseline ECGs was used to trial and compare each model's performance.ResultsThe VCG Model, composed of WCT QRS duration, baseline QRS duration, absolute change in QRS duration, X‐lead QRS amplitude change, Y‐lead QRS amplitude change, and Z‐lead QRS amplitude change, demonstrated effective WCT differentiation (area under the curve [AUC] 0.94) for the derivation cohort. For the validation cohort, the diagnostic performance of the VCG Model (AUC 0.94) was similar to that achieved by the WCT Formula (AUC 0.95), VT Prediction Model (AUC 0.91), WCT Formula II (AUC 0.94), and Hybrid Model (AUC 0.95).ConclusionCustom calculations derived from mathematically synthesized VCG signals may be used to formulate an effective means to differentiate WCTs automatically.

Impact of SMART Pass filter in patients with ajmaline-induced Brugada syndrome and subcutaneous implantable cardioverter-defibrillator eligibility failure: results from a prospective multicentre study.

AimsAjmaline challenge can unmask subcutaneous implantable cardioverter-defibrillator (S-ICD) screening failure in patients with Brugada syndrome (BrS) and non-diagnostic baseline electrocardiogram (ECG). The efficacy of the SMART Pass (SP) filter, a high-pass filter designed to reduce cardiac oversensing (while maintaining an appropriate sensing margin), has not yet been assessed in patients with BrS. The aim of this prospective multicentre study was to investigate the effect of the SP filter on dynamic Brugada ECG changes evoked by ajmaline and to assess its value in reducing S-ICD screening failure in patients with drug-induced Brugada ECGs.Methods and resultsThe S-ICD screening with conventional automated screening tool (AST) was performed during ajmaline challenge in subjects with suspected BrS. The S-ICD recordings were obtained before, during and after ajmaline administration and evaluated by the means of a simulation model that emulates the AST behaviour with and without SP filter. A patient was considered suitable for S-ICD if at least one sensing vector was acceptable in all tested postures. A sensing vector was considered acceptable in the presence of QRS amplitude >0.5 mV, QRS/T-wave ratio >3.5, and sense vector score >100. Of the 126 subjects (mean age: 42 ± 14 years, males: 61%, sensing vectors: 6786), 46 (36%) presented with an ajmaline-induced Brugada type 1 ECG. Up to 30% of subjects and 40% of vectors failed the screening during the appearance of Brugada type 1 ECG evoked by ajmaline. The S-ICD screening failure rate was not significantly reduced in patients with Brugada ECGs when SP filter was enabled (30% vs. 24%). Similarly, there was only a trend in reduction of vector-failure rate attributable to the SP filter (from 40% to 36%). The most frequent reason for screening failure was low QRS amplitude or low QRS/T-wave ratio. None of these patients was implanted with an S-ICD.ConclusionPatients who pass the sensing screening during ajmaline can be considered good candidates for S-ICD implantation, while those who fail might be susceptible to sensing issues. Although there was a trend towards reduction of vector sensing failure rate when SP filter was enabled, the reduction in S-ICD screening failure in patients with Brugada ECGs did not reach statistical significance.Clinical trial registration https://clinicaltrials.gov Unique Identifier NCT04504591.

Assessment of a Novel, 22-lead Mobile Electrocardiogram in Elite, Adolescent Footballers.

The 12-lead electrocardiogram is a key component of cardiac screening in elite adolescent footballers. Current technology hampers mobile electrocardiogram monitoring that could reduce the time-to-diagnosis in symptomatic athletes. Recently, a 22-lead mobile electrocardiogram monitor, CardioSecur (Personal MedSystems GmbH), has been approved for use in adults. In this study, the differences in parameter accuracy between CardioSecur's 22-lead electrocardiogram and the gold standard 12-lead electrocardiogram were assessed in elite adolescent footballers (n=31) using Bland-Altman and paired t-tests/Wilcoxon analysis. Agreement between the two devices was clinically acceptable for heart rate (bias=- 0.633 bpm), PR Interval (bias=- 1.73 ms), Bazzett's corrected QTc interval (bias=2.03 ms), T-wave axis (bias=6.55°), P-wave duration (bias=- 0.941 ms), Q-wave amplitude (bias=0.0195 mV), Q-wave duration (bias=1.98 ms), rhythm (bias=0.0333), ST-segment (bias=- 0.0629), J-point analysis (bias=- 0.01) and extended T wave and QRS duration analysis. Unsatisfactory agreement was observed in QRS axis (bias=- 19.4°), P-wave axis (bias=- 0.670°), QRS amplitude (bias=- 0.660 mV), P-wave amplitude (bias=0.0400 mV) and T-wave amplitude (bias=- 0.0675 mV). CardioSecur's 22-lead electrocardiogram agrees with the gold standard in rhythm, durations, T-wave determination in all leads assessed, permitting its use in adolescent footballers for immediate pitch- or track-side analysis.

A Simple Predictive Marker in Cardiac Resynchronization Therapy Recipients: Prominent S-Wave in Right Precordial Leads.

Background and objectives: Current guidelines criteria do not satisfactorily discriminate responders to cardiac resynchronization therapy (CRT). QRS amplitude is an established index to recognize the severity of myocardial disturbance and might be a key to optimal patient selection for CRT. Materials and Methods: (1) Initial R-wave amplitude, (2) S-wave amplitude, and (3) a summation of maximal R- or R′-wave amplitude and S-wave amplitude were measured at baseline. These parameters were averaged according to right (V1 to V3) or left (V4 to V6) precordial leads. The impact of these parameters on response to CRT, which was defined as a decrease in left ventricular end-systolic volume ≥15% at six-month follow-up, was investigated. Results: Among 47 patients (71 years old, 28 men) who received guideline-indicated CRT implantation, 25 (53%) achieved the definition of CRT responder. Among baseline electrocardiogram parameters, only the higher S-wave amplitude in right precordial leads was an independent predictor of CRT responders (odds ratio: 2.181, 95% confidence interval: 1.078–4.414, p = 0.030) at a cutoff of 1.44 mV. The cutoff was independently associated with cumulative incidence of heart failure readmission and appropriate electrical defibrillation following CRT implantation (p < 0.05, respectively). Conclusions: Prominent S-wave in right precordial leads might be a promising index to predict left ventricular reverse remodeling and greater clinical outcomes following CRT implantation.

Prognostic Value of Electrocardiographic QRS Diminution in Patients Hospitalized With COVID-19 or Influenza

During the clinical care of hospitalized patients with COVID-19, diminished QRS amplitude on the surface electrocardiogram (ECG) was observed to precede clinical decompensation, culminating in death. This prompted investigation into the prognostic utility and specificity of low QRS complex amplitude (LoQRS) in COVID-19. We retrospectively analyzed consecutive adults admitted to a telemetry service with SARS-CoV-2 (n = 140) or influenza (n = 281) infection with a final disposition—death or discharge. LoQRS was defined as a composite of QRS amplitude <5 mm or <10 mm in the limb or precordial leads, respectively, or a ≥50% decrease in QRS amplitude on follow-up ECG during hospitalization. LoQRS was more prevalent in patients with COVID-19 than influenza (24.3% vs 11.7%, p = 0.001), and in patients who died than survived with either COVID-19 (48.1% vs 10.2%, p <0.001) or influenza (38.9% vs 9.9%, p <0.001). LoQRS was independently associated with mortality in patients with COVID-19 when adjusted for baseline clinical variables (odds ratio [OR] 11.5, 95% confidence interval [CI] 3.9 to 33.8, p <0.001), presenting and peak troponin, D-dimer, C-reactive protein, albumin, intubation, and vasopressor requirement (OR 13.8, 95% CI 1.3 to 145.5, p = 0.029). The median time to death in COVID-19 from the first ECG with LoQRS was 52 hours (interquartile range 18 to 130). Dynamic QRS amplitude diminution is a strong independent predictor of death over not only the course of COVID-19 infection, but also influenza infection. In conclusion, this finding may serve as a pragmatic prognostication tool reflecting evolving clinical changes during hospitalization, over a potentially actionable time interval for clinical reassessment.

B-PO01-082 ARTIFICIAL INTELLIGENCE-ASSISTED QRS AMPLITUDE ANALYSIS OF THE PRESENTING ELECTROCARDIOGRAM PREDICTS MORTALITY IN COVID-19

Artificial Intelligence (AI) has shown promise in augmenting ECG analysis. We previously identified QRS amplitude diminution as a predictor of mortality in COVID-19 on follow-up ECG; but ECG data would be most useful clinically if predictive upon admission. To assess whether QRS amplitude on the admission ECG predicts mortality in COVID-19 utilizing AI processing techniques. We performed a retrospective analysis of patients admitted with laboratory confirmed SARS-CoV-2 between March 5 and July 7, 2020 (n=4,709). Patients were excluded if the ECG was not acquired within 72 hrs of admission (n=1,692). Low QRS Amplitude (LoQRS) was defined by a composite of QRS amplitude <5mm in the limb leads AND/OR <10mm in the precordial leads (a composite of V1-V3 and V4-V6). Among 3,012 patients, 373 (14.1%) met criteria for LoQRS (Figure). Compared to patients without LoQRS, these patients had a higher risk of in-hospital mortality (17.4% vs. 10.6%, p<0.001), ICU admission (31.9% vs 22.2%, p<0.001), and mechanical ventilation (26.3% vs 17.5%). Low QRS amplitudes were noted in both limb and precordial leads. In multivariable models, LoQRS was independently associated with mortality (OR 1.55, 95% CI 1.2-2.00, p<0.001) as were age (OR 1.05, 95% CI 1.04-1.06), BMI (OR 1.02, 95% CI 1.01-1.03), and CKD (OR 1.49, 95% CI 1.06-2.12). LoQRS also independently predicted ICU admission (OR 1.7, 95% CI 1.32-2.18) and mechanical ventilation (OR 1.6, 95% CI 1.23-2.00). QRS amplitude on the presenting ECG independently predicts mortality, ICU admission, and mechanical ventilation in hospitalized patients with COVID-19, and may allow initial risk stratification.

B-PO02-197 PATTERNS OF ELECTROCARDIOGRAPH ABNORMALITIES IN CHILDREN WITH HYPERTROPHIC CARDIOMYOPATHY

Hypertrophic cardiomyopathy (HCM) is a heterogeneous cardiac condition with varied manifestations. While ECG abnormalities are commonly seen, their patterns in children with HCM are not well described. Describe the most common ECG patterns in patients presenting with HCM. ECGs collected on 659 children (age 5 days-20 years, median 13 years) with phenotypic HCM were reviewed for abnormalities. Of 659 ECG’s, 13 were eliminated for having paced QRS complexes. Of the remaining 646 ECGs, 82 (12.7%) were normal. The other 564 (87%) had abnormalities identified. LVH (148/646, 23%) and BVH (143/646, 22%) with strain (176/646, 27%) or without strain (148/646, 23%) were the most common findings. Bundle Branch block was observed in 44 patients (44/646, 7%). Strain without hypertrophy occurred in 59 (59/646, 9%) patients. Isolated pathologic Q waves (defined as >0.4 seconds wide, > 3 mm deep or > 25% of the QRS amplitude) were seen in 82 (82/646, 13%). An additional 51 (51/646, 8%) patients with LVH/BVH/RVH or strain pattern had pathologic Q waves. Isolated RVH was seen in 33 patients (33/646, 5%). The presence of a delta wave indicating WPW was seen in 19 (19/646, 3%). Other miscellaneous abnormalities were seen in 36 (36/646, 6%). Patients with HCM can have a normal ECG. The most common ECG abnormality was LVH or BVH with or without “strain”. The next most common abnormality seen was pathologic Q waves. Thus, a significant number of children with HCM have ECG abnormalities that are not typical for “hypertrophy”. Therefore, the presence of the ECG abnormalities described above in a child should prompt further examination with an echo to rule out possible HCM.

B-PO03-159 INTERPRETATION OF PRONE-POSITION 12-LEAD SURFACE ELECTROCARDIOGRAM AND MAIN DIFFERENCES WHEN COMPARED TO SUPINE-POSITION ECGS: INSIGHTS FROM A CASE-CONTROL STUDY

Prone position is a valuable treatment strategy in acute respiratory distress syndrome (ARDS) and is frequently used in surgical scenarios. Nonetheless, prone position may hinder proper acquisition and interpretation of the 12-lead electrocardiogram (ECG) as there is a sparsity of data regarding standardization of lead position and interpretation. We aimed to analyze and compare ECGs in the supine and prone positions to provide guidance for adequate interpretation and clinical utility of the ECG in prone position. This was a multicenter prospective cohort study in which ECGs in the prone and supine position were compared, including patients with COVID-19 infection and healthy controls. The precordial leads for the prone ECGs were placed in the following fashion: V1 in the right paraspinal region at the level of the T7 vertebra, V2 in the left paraspinal region at the level of the T7 vertebra, V4 in the mid-scapular region at the level of the T8 vertebra (approximately bellow the tip of the scapula), V3 halfway between V3 and V4, V5 at the posterior axillary line at the level of the T8 vertebra, and V6 at the mid-axillary line at the level of T8 vertebra - same position as the V6 in the supine position. A total of 45 patients with COVID-19 infection were compared with 40 healthy volunteers (48% of the patients were female, the mean age in the entire cohort was 48.8 years, and the mean BMI was 27.9). The mean heart rate, PR interval, QRS duration, QT and QTc interval, and QRS axis in the frontal plane were found to positively correlate in supine and prone ECGs. The main difference found was no correlation of the QRS amplitude between supine and prone ECGs in leads V1, V2, V3, and V4; but there was positive correlation in leads V5 and V6. Prominent Q waves were present in the anteroseptal leads (V1-V3) in the prone posterior position. In addition, T-wave inversions or flattening were observed in leads V1 and V2 were present in a majority of patients in the prone posterior position. ECGs performed in the prone position are an acceptable alternative to supine ECGs. Special attention and review of prior supine ECGs may be necessary for precise interpretation of the anteroseptal precordial leads which may be misleading (i.e, septal infarct).

HSF1 and GM-CSF expression, its association with cardiac health, and assessment of organ function during heat stress in crossbred Jersey cattle

The study aimed to evaluate the differential expression of HSF1 and GM-CSF mRNA in PBMCs and correlate it with myocardial injury in crossbred Jersey heifers during heat stress. The study also assessed the effect of heat stress on cardiac electrical activity, vascular health, liver function and kidney function. The experiment was conducted in two phases: for heat stressed animals; HS in June (THI ranged from 80.0 to 89.8) and for control group i.e. not exposed to heat stress in January (THI ranged between 70.1 and 71.4). Results of the study revealed that the relative abundance of HSF1 and GM-CSF mRNA increased significantly (P < 0.05) in HS. Serum cardiac biomarkers such as CK-MB, AST and CRP were significantly elevated (P < 0.05) in HS. cTnI was detected ‘positive’ in nineteen out of twenty four cases in HS. Correlation of HSF1 and GM-CSF expression with concentration of LDH, CKMB, CRP and AST in HS was negative but non-significant (P > 0.05). Significant (P < 0.05) ECG findings in HS were increased heart rate, decreased RR interval, decreased PR interval, decreased QRS amplitude and decreased amplitude of P wave. Marked reduction (P < 0.05) in serum cholesterol and triglyceride levels was observed in HS. ALP, AST, bilirubin and urea levels in serum were significantly elevated (P < 0.05) in HS. In conclusion, cardiac enzymes in serum were significantly elevated in HS indicating myocardial injury. HSF1 and GM-CSF mRNA expression alone was inadequate in conferring cytoprotection to cardiac cells in HS. Cardiac electrical activity, vascular status, liver and kidney function were significantly altered in HS.

ECG alarms during left ventricular assist device (LVAD) therapy in the ICU

BackgroundIn hospitalized patients with left ventricular assist device (LVAD), electrical interference and low amplitude QRS complexes are common, which could impact the accuracy of electrocardiographic (ECG) arrhythmia detection and create technical alarms. This could contribute to provider alarm fatigue and threaten patient safety. ObjectivesWe examined three LVAD patients in the cardiac intensive care unit (ICU) to determine: 1) the frequency and accuracy of audible arrhythmia alarms; 2) occurrence rates of technical alarms; and 3) alarm burden (# alarms/hour of monitoring) MethodsSecondary analysis. ResultsDuring 593 h, there were 549 audible arrhythmia alarms and 98% were false. There were 25,232 technical alarms and 93% were for artifact, which was configured as an inaudible text alert. ConclusionFalse-arrhythmia and technical alarms are frequent in LVAD patients. Future studies are needed to identify both clinical and algorithm-based strategies to improve arrhythmia detection and reduce technical alarms in LVAD patients.

Analysis of the determining factors of detectable P-wave and amplitude of QRS complex sensed by implantable loop recorder.

BackgroundDetermining factors for sufficient QRS amplitude and discernible P‐wave sensing in implantable loop recorder (ILR) are unknown. We aimed to investigate determining factors and ILR implantation angle that may improve QRS complex and P‐wave sensing in ILR.MethodsWe retrospectively reviewed 220 patients who underwent ILR implantation or follow‐up analysis. Patient demographic, clinical, echocardiography, electrocardiography, heart angle, and ILR angle data were collected as predictor variables. Associations between ILR QRS amplitude/P‐wave detectability and each predictor variable were investigated.ResultsUnivariate linear regression showed that ILR QRS amplitude was significantly associated with age, height, ILR angle, and QRS amplitudes of 12‐lead electrocardiogram (ECG) (lead I, II, aVR [inverted aVR], aVF, V1–V6) and Holter ECG (lead V3, V5). Among discrete variables, only left ventricular hypertrophy (LVH) affected ILR QRS amplitude (P = .016). A multivariate linear regression analysis revealed that ILR angle (β = −0.008, P < .001), lead aVR amplitude (β = 0.469, P = .003), Holter lead V5 amplitude (β = 0.116, P = .049), Age (β = −0.005, P = .014), and LVH (β = 0.213, P = .031) were independent determinants of ILR QRS amplitude. Logistic regression revealed that heart angle significantly affected ILR P‐wave detectability (β = 0.12, P = .008). Multiple logistic regression revealed that heart angle (β = 0.121, P = .013) and lead V1 amplitude (β = 28.1, P = .034) were independent determinants of ILR P‐wave detectability.ConclusionILR insertion angle, lead aVR QRS amplitude, Holter lead V5 QRS amplitude, age, and LVH are determinants of ILR QRS amplitude. Heart angle and lead V1 P‐wave amplitude of 12‐lead ECG are determinants of ILR P‐wave detectability.

Electrocardiogram Findings Associated With Malignant Pericardial Effusion and Cardiac Tamponade.

Electrocardiogram Findings Associated With Malignant Pericardial Effusion and Cardiac Tamponade.

Predicting inappropriate S-ICD® episodes by simple 12-lead surface ECG parameters

AimsThe present study aims at analyzing the role of a preimplantation 12-lead electrocardiogram (ECG) on the prediction of inappropriate S-ICD® episodes. MethodsN=116 screened patients (pts) with an S-ICD® and a follow-up of at least 6 months were included. A preimplantation 12-lead ECG (50 mm/s, 10 mm/mV) was analyzed with regard to QRS and T-wave amplitude, T wave concordance or discordance and QRS/T wave ratio in all 12 leads. To ensure an exact determination of parameters Datinf® Measure software was used. Results were correlated to the occurrence of oversensing of cardiac signals during follow-up. ResultsN = 116 pts. (63,8% male, mean age 40,9 ± 15,5 years) were included (primary prevention in 47.4% of pts). The most frequent cardiac diseases were hypertrophic cardiomyopathy (HCM) in n = 25 (21,6%), electrical heart disease in n = 20 (17,2%), and dilated cardiomyopathy in n = 17 (14,7%). Mean follow-up was 740 ± 549 days. During follow- up n = 17 (14.7%) pts. experienced n = 27 inappropriate episodes due to T-wave oversensing. Besides HCM (OR 6.16, CI 1.79–21.15, p = 0.004) a discordance of QRS to T-wave in lead I (OR 6.5, CI 1.86–22.67, p = 0.003) was found to be a strong predictor for inappropriate shocks. In multivariate analysis the pts. with a combination of both had an 8.4-fold higher risk of misclassification of intracardiac signals (p = 0.003) with consecutive inappropriate therapy. ConclusionA discordance of QRS to T-wave in lead I turned out to be a strong predictor for future inappropriate shocks in a typical S-ICD® cohort with special impact on HCM pts.

Abstract P087: Goldberger's Electrocardiographic Criteria For Left Ventricular Dysfunction Associated With Increased Mortality

Goldberger’s Electrocardiographic Criteria for Left Ventricular Dysfunction Associated with Increased Mortality Introduction: The ability of the Goldberger electrocardiographic (ECG) triad criteria to detect left ventricular dysfunction (LVD) is well-established. However, the prognostic significance of this triad as a predictor of poor outcomes is not known. Hypothesis: We hypothesized that the Goldberger ECG-LVD triad is associated with increased all-cause mortality and cardiovascular mortality in the general population. Methods: This analysis included 8,426 participants (60.5 ± 13.6 years, 51.5% women, 50% non-Hispanic white) from the Third National Health and Nutrition Examination Survey. The Goldberger ECG-LVD triad was defined as follows: high precordial QRS voltage (SV1 or SV2 + RV5 or RV6 ≥3500 μV); low limb lead QRS voltage (mean QRS amplitude in each of the limb leads ≤ 800 μV); and poor R wave progression (RV4/SV4 &lt;1). Mortality was ascertained using the National Death Index. Results: At baseline, 1,384 (47.3%) of the participants had at least one of the criteria of Goldberger triad (1,193 had only one and 191 participants had 2 or more). During a median follow up of 13.8 years, 3,184 deaths occurred, of which 1,405 were cardiovascular. In multivariable-adjusted Cox proportional hazards models, presence of at least one of the Goldberger triad criteria (vs. none) was associated with increased risk of all-cause (HR 1.17, 95% CI 1.08 – 1.26, p = &lt;0.0001) and cardiovascular mortality (1.19, 1.06 – 1.33, p = 0.003). Conclusion: The Goldberger ECG-LVD triad for left ventricular dysfunction is associated with increased all-cause and cardiovascular mortality and may offer prognostic value, in addition to its diagnostic utility.

Usefulness of Goldberger"s triad to select dilated cardiomyopathy

Abstract Funding Acknowledgements Type of funding sources: None. Background Background: In 1982, Goldberger described an electrocardiographic triad (SV1 or SV2 +RV5 or RV6 ≥3.5mV, total QRS amplitude in limb leads ≤0.8mV, and R/S ratio &amp;lt; 1 in lead V4) that was 70% sensitive and &amp;gt;90% specific for detecting severe left ventricular (LV) dysfunction. The pathophysiology of this highly specific ECG triad probably relates to a number of mechanical and vectorial factors associated with congestive heart failure of a variety of etiologies. Left ventricular enlargement causes increased precordial voltage. The horizontal plane vector shifts posteriorly, orthogonal to the frontal plane, causing poor R wave progression and low limb lead voltage. Finally, increased extracellular fluid may preferentially attenuates QRS voltage in the limb leads. Objective To test the sensitivity of this triad in patients with non-ischaemic cardiomyopathy and severe left ventricular systolic dysfunction Methods Methods: 386 patients mean age 62.45 ± 13.96 years, male 72%, NYHA II-IV, with non-ischaemic cardiomyopathy, 70 had bundle branch block (18%) and mean left ventricular ejection fraction(EF) 22.57 ± 8.62%. 76% hypertension, 39% diabetes mellitus, 32% atrial fibrillation. The electrocardiographic triad was sought in the ECG recorded at time of the echocardiographic study. The mean LV end-diastolic diameter was 5.81 ± 1.53 cm. Result Results: 56% patients had SV1 or SV2 +RV5 or RV6 ≥3.5mV, 85% patients had R/S ratio &amp;lt; 1 in lead V4, 19% had total QRS amplitude in limb leads ≤0.8mV. 50% patients had SV1 or SV2 +RV5 or RV6 ≥3.5mV and R/S ratio &amp;lt; 1 in lead V4. Only 6% patients fulfilled the triad. Conclusions Conclusion: Goldberger"s triad is an insensitive marker for severe LV dysfunction. Using SV1 or SV2 +RV5 or RV6 ≥3.5mV and R/S ratio &amp;lt; 1 in lead V4 had a sensitivity of 50%. 85% patients had R/S ratio &amp;lt; 1 in lead V4. R/S ratio &amp;lt; 1 in lead V4 is a simple way to select dilated LV.