Baseline Electrocardiogram Research Articles

Abstract P415: Correlation of Screening Electrocardiogram, Transthoracic Echocardiogram, and ASCVD Risk Score to 10 Year ASCVD Outcomes Among Asymptomatic Community Dwelling Women

Background: The efficacy and value of non-traditional screening methods such as electrocardiogram (ECG) and transthoracic echocardiography(TTE) remain unknown. In this study, we examined the correlation between initial ECG and TTE findings, and atherosclerotic cardiovascular disease (ASCVD) 10 year risk score with actual 10-year ASCVD outcomes among asymptomatic women from a community-based screening program cohort at Rush University Medical Center. Methodology: A 10-year follow-up survey was conducted in March-September 2018 from the 355 participants from the initial 2BigHearts community screening program in 2007. Demographics, past medical history, ASCVD outcomes (stroke, non-fatal MI, PAD), and self-reported medication lists were obtained from the 107 participants who responded to the survey. Pearson Chi-square Test was used to determine the association of ECG, TTE, and calculated ASCVD risk score with ASCVD outcomes and heart failure(HF). Results: Amongst the 107 participants (mean age 63±10.6 years, 68.3% (71/104) Caucasian, 18.3% (19/104) African American, 8.6% (9/104) Hispanic, 4.8% (5/104) Asian), 15% (16/107) had baseline TTE abnormality with chamber enlargement as most common while 29.9% (32/107) had baseline ECG abnormality with conduction abnormalities as most common. The mean ASCVD 10 year risk score was 4.02%±4.5%. Of the 107, 11 had ASCVD score ≥ 7.5% of which 2 developed non-fatal MI and PAD. Other co-morbid conditions included 29% (31/107) hyperlipidemia, 22.4% (24/107) hypertension, 8.4% (9/107) diabetes, 6.5% (7/107) obstructive sleep apnea and 12.1% (13/107) any type of cancer. Chi-square testing showed no statistically significant correlation between ECG or TTE abnormality with ASCVD outcome (p=0.251 ECG, p=0.461 TTE). Baseline ASCVD risk score of ≥7.5% was associated with 10-year ASCVD outcome (p=0.003) and abnormal TTE at baseline was associated with heart failure in 10-year follow-up (p=0.017). Conclusion: This study found no association between abnormal screening ECG and TTE findings with 10-year ASCVD outcomes (stroke, non-fatal MI, PAD). However, abnormal TTE findings are associated with HF. ASCVD pooled cohort equation proved to be better than ECG and TTE in predicting ASCVD outcomes.

Acute Management of VentricularArrhythmia inPatients WithSuspectedInherited HeartRhythmDisorders.

After the most common causes of sudden cardiac death including ischemic and structural heart disease have been ruled out, clinicians on the front lines of emergent medical care can be faced with unexplained and recurrent life-threatening arrhythmia episodes in children and adults. In these cases, an inherited arrhythmia syndrome should be suspected, and a departure from conventional advanced cardiac life support algorithms may be required. This review focuses on the electrocardiographic clues of an inherited arrhythmia syndrome that can be uncovered through a careful analysis of the baseline electrocardiogram (ECG) and classification of the presenting ventricular arrhythmia and its mode of onset. After presenting an informed working diagnosis and an explanation of the implied electrophysiologic mechanisms, discussion provides a protocol approach to acute and subacute management decisions. Careful attention to a patient's response to treatment and its ECG surrogates have the potential to facilitate tailored therapy based on the underlying arrhythmogenic substrate and pathophysiology.

The WCT Formula: A novel algorithm designed to automatically differentiate wide-complex tachycardias

BackgroundThe accurate differentiation of wide complex tachycardias (WCTs) into ventricular tachycardia (VT) or supraventricular wide complex tachycardia (SWCT) remains problematic despite numerous manually-operated electrocardiogram (ECG) interpretation methods. We sought to create a new WCT differentiation method that could be automatically implemented by computerized ECG interpretation (CEI) software. MethodsIn a two-part study, we developed and validated a logistic regression model (i.e. WCT Formula) that utilizes computerized measurements and computations derived from patients' paired WCT and subsequent baseline ECGs. In Part 1, a derivation cohort of paired WCT and baseline ECGs was examined to identify independent VT predictors to be incorporated into the WCT Formula. In Part 2, a separate validation cohort of paired WCT and baseline ECGs was used to prospectively evaluate the WCT Formula's diagnostic performance. ResultsThe derivation cohort was comprised of 317 paired WCT (157 VT, 160 SWCT) and baseline ECGs. A logistic regression model (i.e. WCT Formula) incorporating WCT QRS duration (ms) (p < 0.001), frontal percent amplitude change (%) (p < 0.001), and horizontal percent amplitude change (%) (p < 0.001) yielded effective WCT differentiation (AUC of 0.96). The validation cohort consisted of 284 paired WCT (116 VT, 168 SWCT) and baseline ECGs. The WCT Formula achieved favorable accuracy (91.5%) with strong sensitivity (89.7%) and specificity (92.9%) for VT. ConclusionThe WCT Formula is an example of how contemporary CEI software could be used to successfully differentiate WCTs. The incorporation of similar automated methods into CEI software may improve clinicians' ability to accurately distinguish VT and SWCT.

Late presentation of arrhythmogenic right ventricular cardiomyopathy in an octogenarian associated with a pathogenic variant in the plakophilin 2 gene: a case report

BackgroundArrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited myocardial disease characterized by fibrofatty replacement and ventricular arrhythmias. ARVC is believed to be a disease of the young, with most cases being diagnosed before the age of 40 years. We report here a case of newly diagnosed ARVC in an octogenarian associated with a pathogenic variant in the plakophilin 2 gene (PKP2).Case presentationAn 80-year-old Japanese man was referred for sustained ventricular tachycardia. His baseline electrocardiogram showed negative T waves in V1–V4. Right ventriculography showed right ventricular aneurysm. Because this case met three major criteria, ARVC was diagnosed. He was successfully treated with radiofrequency ablation and oral amiodarone. Genetic analysis identified an insertion mutation in exon 8 of PKP2 (1725_1728dupGATG), which caused a frameshift and premature termination of translation (R577DfsX5).ConclusionsTo the best of our knowledge, this is the first report of newly diagnosed ARVC in an octogenarian associated with a loss-of-function PKP2 pathogenic variant. Although the late clinical presentation of ARVC is rare, it should be included in the differential diagnosis when treating older patients with ventricular tachyarrhythmias.

Risk factors for the development of atrial fibrillation on ibrutinib treatment

Ibrutinib increases the risk of atrial fibrillation (AF), but the associated risk factors are not clearly defined. We performed retrospective review of ibrutinib-treated patients in a large academic practice to identify risk factors for new-onset AF. Variables with p-values <.05 in logrank analysis were included as pairs in two-variable Cox regression. Of the 168 patients treated with ibrutinib, 60.7% had chronic lymphocytic leukemia/small lymphocytic lymphoma and 39.3% other histologies. The incidence of AF was 11.9% after a median 154-day ibrutinib exposure. Only heart failure (hazard ratio, 95% confidence interval; 14.1, 5.3–37.2) and left atrial abnormality on electrocardiogram (5.4, 1.9–15.4) were independently significant in paired Cox regression. Eighty-seven percent of patients with HF satisfied Framingham clinical criteria. As structural heart disease is a strong risk factor for incident AF, we emphasize the importance of baseline electrocardiogram, recommend baseline clinical screening for HF and, in specific instances, a baseline echocardiogram.

Salivary uric acid and telomere length in African American men and women

Differentiation of wide complex tachycardias (WCTs) into ventricular tachycardia (VT) or supraventricular wide complex tachycardia (SWCT) using conventional manually-operated electrocardiogram (ECG) interpretation methods is difficult. Recent research has shown that accurate WCT differentiation may be accomplished by automated approaches (e.g., WCT Formula) implemented by computerized ECG interpretation software.We sought to develop a new automated means to differentiate WCTs.First, a derivation cohort of paired WCT and baseline ECGs was examined to secure independent VT predictors to be incorporated into a logistic regression model (i.e., WCT Formula II). Second, the WCT Formula II was trialed against a separate validation cohort of paired WCT and baseline ECGs.The derivation cohort comprised 317 paired WCT (157 VT, 160 SWCT) and baseline ECGs. The WCT Formula II was composed of baseline QRS duration (p = 0.02), WCT QRS duration (p < 0.001), frontal percent time-voltage area change (p < 0.001), and horizontal percent time-voltage area change (p < 0.001). The area under the curve (AUC) for VT and SWCT differentiation was 0.96 (95% CI 0.94–0.98) for the derivation cohort. The validation cohort consisted of 284 paired WCT (116 VT, 168 SWCT) and baseline ECGs. WCT Formula II implementation on the validation cohort yielded effective WCT differentiation (AUC 0.96; 95% CI 0.94–0.98).The WCT Formula II is an example of how contemporary ECG interpretation software could be used to differentiate WCTs successfully.

Idiopathic Ventricular Fibrillation and Otherwise Normal Electrocardiograms

Background: Idiopathic ventricular fibrillation (IVF) in patients with normal baseline electrocardiograms (ECGs) is a rare disease. Little information is available on the clinical features and long-term follow-up of out-of-hospital cardiac arrest (OHCA) survivors presenting with true IVF and 12-lead ECGs that remain normal over time. Objective: To define the clinical and ECG characteristics, as well as long-term clinical outcomes of a large cohort of survivors of OHCA due to true IVF. Methods: OHCA survivors with VF as the presenting rhythm, normal baseline and follow-up ECGs with no signs of cardiac channelopathy including early repolarization or atrioventricular (AV) conduction abnormalities, and without structural heart disease were included in a registry. Results: A total of 245 OHCA survivors with IVF (median age: 38 years; males 59%) were recruited from 25 centres. All had normal baseline and follow-up ECGs, and no evidence of structural heart disease. An implantable cardioverter-defibrillator (ICD) was implanted in 226 patients (92%), while 18 patients (8%) were treated with drug therapy only. Over a median follow-up of 63 months (interquartile range: 25-110 months), 12 patients died (5%); in 4 of them (1.6%) the lethal event was of cardiac origin. Patients treated with antiarrhythmic drugs (AADs) only had a higher rate of cardiovascular death compared to patients who received an ICD (16% vs. 0.4%, p=0.001). The ECG and echocardiogram of all patients remained unchanged over time. Fifty-two patients (21%) experienced an arrhythmic recurrence. Age ≤ 16 years at the time of the first ventricular arrhythmia was the only predictor of arrhythmic recurrence on multivariable analysis (HR 0.41, 95% CI 0.18-0.92, p=0.03). Discussion: OHCA survivors of true IVF with normal baseline and follow-up ECGs frequently have arrhythmic recurrences, but a good prognosis when treated with an ICD. Children are a category of IVF patients at higher risk of arrhythmic recurrences. Funding: The study was supported by a grant of the Swiss Heart Foundation. Declaration of Interest: G.C. has received a research grant from the Swiss National Foundation. P.L. has received speaker fees and research grants from Boston Scientific, Abbott and Medtronic Research support from UCLH Biomedicine NIHR. F.L. is consultant and has received research support from Medtronic Plc, Abbott, Boston Scientific and Microport. S.B. has received speaker’s bureau from Medtronic and Microport. C.P. has received research grant from Biotronik and Biosense Webster. P.B. is consultant for Biotronik. A.A. is consultant to Abbott, Biosense Webster, Daiichi-Sankyo, Boston Scientific, Medtronic, Microport-CRM; and has received speaker fee from Daiichi-Sankyo, Boston Scientific, Medtronic, Microport-CRM Ethics Approval Statement: Data were collected in accordance with regulations set by the local Institutional Ethics Committee and/or Institutional Review Board.

Progression of Baseline Electrocardiogram Abnormalities in Chagas Patients Undergoing Antitrypanosomal Treatment.

BackgroundThe objective of the study was to better understand the impact of antitrypanosomal treatment on the evolution of Chagas-related, prognostically important electrocardiogram (ECG) abnormalities.MethodsInitial and posttreatment ECGs were obtained in a prospective cohort of Chagas patients treated with nifurtimox or benznidazole and compared to an untreated cohort. Electrocardiogram disease progression was compared in those with and without baseline abnormalities pre- and posttherapy.ResultsFifty-nine patients were recruited in the treatment arm and followed for an average of 3.9 years. There were no differences between ECG groups with regards to follow-up, age, baseline ejection fraction, or therapy. In the treated cohort, 0 of 30 patients with normal ECGs developed an abnormal ECG compared with 7 of 29 patients with baseline ECG abnormalities who developed new ECG abnormalities (P = .005). In an untreated cohort of 30 patients, 3 of 7 with normal ECGs developed an abnormality compared with 14 of 23 patients with baseline abnormalities (P = .67). Untreated patients had a higher likelihood of developing new EKG abnormalities (56.7% vs 11.9%, P < .001) despite shorter follow-up, and in a multivariate analysis adjusting for baseline EKG status across both treated and untreated cohorts, treated patients were still less likely to have progression of their EKG disease (odds ratio = 0.13, P < .001). The corrected QT (QTc) interval was not significantly affected by either study medication (415 vs 421 ms, initial vs posttreatment QTc; P = .06).ConclusionsOver an average follow-up of 3.9 years, treated patients with normal baseline ECGs did not have significant changes during a course of treatment; however, those with baseline abnormal ECGs had significant progression of their conduction system disease despite treatment, and those without treatment also experienced a progression of ECG disease. These preliminary results suggest that Chagas patients with normal ejection fraction and normal ECG may benefit the most from antitrypanosomal treatment.

Половые аспекты реактивности проводящей системы сердца у подростков во время велоэргометрии в зависимости от типа организации электроэнцефалограммы

The aim of the study was to evaluate the dependence of the heart conduction system on the electroencephalogram (EEG) type during a bicycle ergometry test (BET) in adolescents 15-17 years. 89 boys and girls with autonomic dysfunction syndrome (ADS) and 28 healthy adolescents 15-17 years were examined. Stages of the study included the baseline EEG and electrocardiogram (ECG), BET, ECG after BET in rest period. Тhe most pronounced shortening of the ECG-intervals PQ, QT and QTc in the rest period after BET regarding to the baseline values, shortening of the PQ interval during the rest period after BET wеre revealed in girls with ADS and paroxysmal EEG phenomena. Shortening of the PQ ECG-interval at the end of the rest period after BET regarding to the baseline values were revealed in boys with ADS and diffuse EEG-changes, desynchronous alpha-rhythm EEG. There was no shortening of the QTс ECG-interval in the first minute of the rest period after BET regarding to the baseline values in boys with ADS and paroxysmal EEG phenomena. Вut at the same time increase of the QTс interval at the end of the rest period after BET were revealed in boys of the same group. It is concluded that adolescents with ADS, diffuse EEG-changes, paroxysmal EEG phenomena have a high risk of bioelectric heart disturbances during physical activity.

Myocarditis in a patient treated with Nivolumab and PROSTVAC: a case report

BackgroundImmune checkpoint inhibitors have revolutionized treatment and improved survival in many cancers. However, since immune-related adverse events (irAEs) are potentially fatal, early recognition and prompt treatment are warranted. One of the rarest but most dramatic irAE is myocarditis, which has significant morbidity and mortality if not recognized and treated early.ObjectiveTo report the first case of myocarditis in a patient with metastatic castration-resistant prostate cancer (mCRPC) treated with a combination of nivolumab, an anti-programmed cell death protein 1 antibody, and PROSTVAC, a vector-based therapeutic prostate cancer vaccine.Case ReportA 79-year-old man with mCRPC metastatic to bone and lymph nodes and a history of atrial fibrillation presented with blurred vision and pain and stiffness in the upper back after 8 weeks on a clinical trial with nivolumab (1 mg/kg) and PROSTVAC, both given every 2 weeks. Eye exam was within normal limits, while musculoskeletal exam revealed tenderness in trapezius muscles and decreased motor strength in arms (III/V) and neck (IV/V). The rest of the physical exam was within normal limits, with the exception of an irregular heart rhythm. Laboratory tests were as follows: creatinine kinase (CK) 3200 U/L (normal: 39–308 U/L), CK-MB 65.7 mcg/L (normal: 0–7.6 mcg/L), troponin I 0.209 ng/mL (normal: 0–0.056 ng/mL). Electrocardiogram (ECG) revealed atrial fibrillation with QT prolongation (QTc 514 msec) and left anterior fascicular block, unchanged from baseline. 2D-echocardiogram showed a left ventricular ejection fraction of 65% with an enlarged left atrium, dilated right ventricle, and increased pulmonary artery pressure (45 mmHg). ProBNP was elevated at 1463 pg/mL and peaked at 3066 pg/mL one day after hydration. With a presumed diagnosis of autoimmune myositis and possible myocarditis, the patient was admitted and started on methylprednisolone 1 mg/kg/day. Cardiac MRI showed elevated native myocardial T1 values consistent with myocarditis (Fig. 1). The patient was discharged on a prednisone taper after normalization of cardiac enzymes on day 4. Treatment with PROSTVAC continued for three more months; nivolumab was discontinued. Six months later, patient is doing well, with no residual cardiac damage.DiscussionCardiovascular irAEs are relatively rare (< 1%) and have a variety of clinical presentations. Myocarditis is potentially life-threatening and can range from subclinical to fulminant. Therefore, clinical suspicion, early detection, and prompt treatment are imperative (1). The initial diagnostic workup should include cardiac enzymes, ECG, and 2D-echocardiogram. The most commonly observed ECG changes are generalized repolarization abnormalities, prolonged QT interval, and conduction abnormalities (2). An elevated troponin I in the absence of overt coronary artery disease is suggestive of myocarditis and should be evaluated further. Myocardial biopsy is the standard diagnostic procedure; however, a cardiac MRI can achieve a diagnosis when biopsy is not feasible (3). Advancements in parametric mapping techniques have allowed the use of native myocardial T1 in the detection of myocarditis, as it has superior diagnostic performance and higher sensitivity than older parameters (3). Our patient had been treated with an immune checkpoint inhibitor and a therapeutic cancer vaccine to induce effective antitumor activity through immunogenic intensification and presented with muscle stiffness and elevated CK. Although he had no new cardiovascular symptoms, cardiac enzymes were tested to rule out myocardial involvement. MRI with gadolinium confirmed the diagnosis of myocarditis. To date, none of the 1360 patients treated with PROSTVAC as a single agent have developed myocarditis, while myocarditis has been rarely reported in patients treated with nivolumab (< 1%) (1). Whether the combination of PROSTVAC and nivolumab presents an additional risk of myocarditis is unclear. To our knowledge, this is the first case of myocarditis in a patient with mCRPC receiving simultaneous treatment with an immune checkpoint inhibitor and a prostate cancer vaccine.Our experience highlights the importance of suspicion and early intervention in patients who present with cardiac abnormalities after receiving cancer immunotherapy. We propose following protocol: baseline troponin, ECG, and 2D-echocardiogram prior to treatment, then repeated troponin at 2, 4, and 12 weeks post-treatment, then monthly. If troponin becomes positive without alternative explanation, myocarditis should be ruled out with cardiac MRI or myocardial biopsy, and patient should be admitted for treatment with high-dose steroids as early intervention may minimize myocardial injury.

Attitudes, Beliefs, and Practices of Pediatric Palliative Care Physicians Regarding the Use of Methadone in Children With Advanced Cancer

ContextMethadone is a long-acting opioid known for its unique pharmacokinetic and pharmacodynamic properties. Most research on methadone in children is limited to its effect on the prolongation of the corrected QT (QTc) interval. ObjectivesTo better understand the attitudes, beliefs, and practices of pediatric palliative care physicians regarding the use of methadone in children with advanced cancer. MethodsA survey was sent to the American Academy of Pediatrics Section of Hospice and Palliative Medicine LISTSERV. Information on demographics, dosing of methadone, and the use of electrocardiograms (ECGs) was collected. ResultsOne-hundred and five respondents (91%) provide palliative care to children ≥ 50% of the time, and a majority (81, 77%) prescribe methadone. Most (62, 77%) physicians were board certified in Hospice and Palliative Medicine, and most (39, 63%) certified via the direct pathway (“grandfathering”). Most physicians (57, 70%) do not use loading doses of methadone. Board-certified physicians trended toward decreasing methadone dose more (40% ± 19%) than non–board-certified physicians (28%, ±20%) when changing from the oral to intravenous route (P = 0.07). Respondents defined a QTc interval as “prolonged” (mean ± SD) at 444 milliseconds (±68 milliseconds). The percentage of patients receiving a baseline ECG was 65% (±33%). The most common reason for not performing a baseline ECG was that the patient was on hospice (13, 36%). ConclusionsThere are consistent practices, attitudes, and beliefs of pediatric palliative care providers with regard to methadone. More education is needed on the accurate value of a prolonged QTc interval.

Split Intracardiac Potentials

A 58-year-old female patient presented with monomorphic ventricular tachycardia (right bundle branch block with inferior axis). The baseline electrocardiogram was normal. Her 2-dimensional echocardiogram revealed a hyperechoic septum with preserved left ventricular systolic function ([Figure 1A-H][1

Electrocardiographic left atrial abnormality and silent vascular brain injury: The Northern Manhattan Study.

HypothesisWe hypothesized that P wave terminal Force in the V1 lead (PTFV1) would be associated with leukoaraiosis and subclinical infarcts, especially cortical infarcts, in a population-based, multi-ethnic cohort.MethodsPTFV1 was collected manually from baseline electrocardiograms of clinically stroke-free Northern Manhattan Study participants. Investigators read brain MRIs for superficial infarcts, deep infarcts, and white matter hyperintensity volume (WMHV). WMHV was adjusted for head size and log transformed, achieving a normal distribution. Logistic regression models investigated the association of PTFV1 with cortical and with all subclinical infarcts. Linear regression models examined logWMHV. Models were adjusted for demographics and risk factors.ResultsAmong 1174 participants with PTFV1 measurements, the mean age at MRI was 70 ± 9 years. Participants were 14.4% white, 17.6% black, and 65.8% Hispanic. Mean PTFV1 was 3587.35 ± 2315.62 μV-ms. Of the 170 subclinical infarcts, 40 were cortical. PTFV1 ≥ 5000 μV-ms was associated with WMHV in a fully adjusted model (mean difference in logWMHV 0.15, 95% confidence interval 0.01–0.28). PTFV1 exhibited a trend toward an association with cortical infarcts (unadjusted OR per SD change logPTFV1 1.30, 95% CI 0.94–1.81), but not with all subclinical infarcts.ConclusionElectrocardiographic evidence of left atrial abnormality was associated with leukoaraiosis.

Impact of Baseline Atrial Fibrillation on Outcomes Among Women Who Underwent Contemporary Transcatheter Aortic Valve Implantation (from the Win-TAVI Registry)

Pre-existing atrial fibrillation (AF) is common among patients who underwent transcatheter aortic valve implantation (TAVI) and has been associated with adverse outcomes. The specific impact of AF at baseline in women who underwent TAVI, however, remains unknown. The Women's International Transcatheter Aortic Valve Implantation is a prospective, multinational registry evaluating the safety and performance of contemporary TAVI in women in 19 centers between January 2013 and December 2015. Patients with available electrocardiogram at baseline were compared according to the presence of AF. All events were adjudicated according to the Valve Academic Research Consortium 2 criteria. Associations between AF and outcomes were tested using multivariate Cox regression model. Of the 993 women with available baseline electrocardiogram included in the study, 200 (20.1%) presented with AF. Patients with AF at baseline had higher Euroscore I score values and more frequently had chronic kidney disease or prior stroke. Patients without AF more frequently had coronary artery disease. There was no difference regarding in-hospital events between the two groups aside from longer length of stay for patients with AF (13.3 ± 11 vs 11.5 ± 7.1 days, p = 0.01). In multivariate analysis, AF at baseline was associated with an increase of all-cause and cardiovascular death at 12 months (adjHR 1.67 95%CI 1.11 to 2.50, p = 0.013 and adjHR 1.85 95%CI 1.19 to 2.86, p = 0.006 respectively). In conclusion, in this prospective registry of women who underwent contemporary TAVI, the presence of AF at baseline was associated with significantly increased 12-month mortality.

Vectorcardiographic QRS area is associated with long-term outcome after cardiac resynchronization therapy

Recent studies have suggested that vectorcardiographic measures predict left ventricular (LV) reverse remodeling and clinical outcome in patients receiving cardiac resynchronization therapy (CRT). The objectives of this study were to compare predictive abilities of different vectorcardiographic measures (QRS area and sum absolute QRS-T integral) and transformation methods (Kors and inverse Dower) and to assess the independent association between the best predictor and outcomes in CRT recipients. This retrospective study included CRT recipients with a digital baseline electrocardiogram, QRS duration ≥120 ms, and ejection fraction ≤35%. The end point was a composite of heart transplantation, LV assist device implantation, or all-cause death. Analyses were performed for the overall cohort and for a prespecified subgroup of patients with left bundle branch block (LBBB). Of 705 included patients with a mean age of 66.6 ± 11.5 years, 492 (70%) were men, 374 (53%) had ischemic heart disease, and 465 (66%) had LBBB. QRS area from vectorcardiograms derived via the Kors transformation demonstrated the best predictive value. In multivariable Cox regression, patients with a smaller QRS area (≤95 μVs) had an increased hazard in the overall cohort (adjusted hazard ratio 1.65; 95% CI 1.25-2.18 P < .001) and in the LBBB subgroup (adjusted hazard ratio 1.95; 95% CI 1.38-2.76 P < .001). QRS area was associated with outcome in patients with QRS duration <150 ms (unadjusted hazard ratio 3.85; 95% CI 2.02-7.37 P<.001) and in patients with QRS duration ≥150 ms (unadjusted hazard ratio 1.76; 95% CI 1.32-2.34 P < .001). Vectorcardiographic QRS area is associated with survival free from heart transplantation and LV assist device implantation in CRT recipients.

Association between typical electrocardiographic abnormalities and NT-proBNP elevation in a large cohort of patients with Chagas disease from endemic area

Chagas cardiomyopathy is the most harmful complication of Chagas disease. The electrocardiogram is a well-studied exam and has been considered an important tool for detection and evaluation of Chagas cardiomyopathy since the first years of its description. Many of its abnormalities have been described as associated with a worse prognosis. Serum BNP levels were described as inversely related to the left ventricular ejection fraction and as an independent predictor of death. It was not reported how electrocardiographic alterations correlate to NT-proBNP and its analog. The present study aims to describe the baseline electrocardiograms of a large cohort of patients with Chagas disease from endemic area and to establish an association between the number of electrocardiogram alterations and high levels of NT-ProBNP in Chagas disease patients. This study selected 1959 Chagas disease patients in 21 municipalities within a limited region in the northern part of the State of Minas Gerais (Brazil), 1084 of them had Chagas cardiomyopathy. NT-proBNP levels were suggestive of heart failure in 11.7% of this population. One or more electrocardiographic alterations have an Odds Ratio of 9.12 (CI 95% 5.62–14.80) to have NT-proBNP elevation. Considering the association between the number of 1, 2, and 3 or more alterations in electrocardiogram and NT-proBNP elevation, the ORs were 7.11 (CI 95% 4.33–11.67); 16.04 (CI 95% 9.27–27.77) and 47.82 (CI 95% 17.98–127.20), respectively. The presence and the number of typical electrocardiographic alterations of Chagas disease are independently associated with the severity of the cardiomyopathy.

In the transition from fibrinolysis to primary PCI, the HERO trials help refine STEMI ECG interpretation and Q wave analysis potentially alters future management.

Electrocardiogram sub-studies from the Hirulog Early Reperfusion/Occlusion 1 and 2 trials, which tested bivalirudin as an adjunctive anticoagulant to fibrinolysis in ST-elevation myocardial infarction, have contributed to the literature. The concept of using the presence of infarct lead Q waves to determine reperfusion benefit has subsequently been explored in multiple primary percutaneous coronary intervention studies. The angiographic findings before percutaneous coronary intervention combine with the baseline electrocardiogram to accurately diagnose ST-elevation myocardial infarction and evaluate its potential territory. This review discusses the relative merits of the presence of infarct lead Q waves versus time duration from symptom onset using observational data from cohorts of patients from multiple clinical trials. The presence of infarct lead Q waves at presentation has been repeatedly shown to be superior to time duration from symptom onset in determining prognosis, despite that continuous variable (time duration) statistically should be more powerful than dichotomous variable (Q wave). If quantitative or semi-quantitative measurement of Q waves correlates well with irreversible myocardial injury in vivo (a research goal of many cardiac magnetic resonance imaging studies), Q waves measurements by mirroring ST-elevation myocardial infarction evolution better than the current metric of time duration of symptoms will impact future ST-elevation myocardial infarction reperfusion management. Newer methodology will more quickly capture and transmit electrocardiogram information including infarct lead Q waves potentially before first medical contact, and help differentiate new evolving Q waves of the ongoing ST-elevation myocardial infarction from old changes. Q waves as the new metric in ST-elevation myocardial infarction reperfusion should be tested in upcoming trials.

Diurnal Profile of the QTc Interval Following Moxifloxacin Administration.

Understanding the physiological fluctuations in the corrected QT (QTc) interval is important to accurately interpret the variations in drug-induced prolongation. The present study aimed to define the time course of the effect of moxifloxacin on the QT interval to understand the duration of the responses to moxifloxacin. This retrospective analysis was performed on data taken from a thorough QT 4-way crossover study with 40 subjects. Each period consisted of a baseline electrocardiogram (ECG) day (day -1) and a treatment day (day 1). On both days, ECGs were recorded simultaneously using 2 different systems operating in parallel: a bedside ECG and a continuous Holter recording. The subjects were randomized to 1 of 4 treatments: 5mg and 40mg of intravenous amisulpride, a single oral dose of moxifloxacin (400mg), or placebo. Standardized meals, identical in all 4 periods, with similar nutritional value were served. Bedside ECG results confirmed that the moxifloxacin peak effect was delayed in the fed state and showed that the Fridericia corrected QT prolongation induced by moxifloxacin persisted until the end of the 24-hour measurement period. The use of continuous Holter monitoring provided further insight, as it revealed that the moxifloxacin effect on QTc was influenced by diurnal and nocturnal environmental factors, and hysteresis effects were noticeable. The findings suggested that moxifloxacin prolongs QTc beyond its elimination from the blood circulation. This is of relevance to current concentration-effect modeling approaches, which presume the absence of hysteresis effects.

Resting Heart Rate Variability (HRV) in Adolescents and Young Adults from a Genetically-Informed Perspective.

Reduced heart rate variability (HRV) is associated with cardiac morbidity, mortality, and negative psychopathology. Most research concerning genetic influences on HRV has focused on adult populations, with fewer studies investigating the developmental period of adolescence and emerging adulthood. The current study estimated the genetic and environmental contributions to resting HRV in a sample of twins using various HRV time domain metrics to assess autonomic function across two different time measurement intervals (2.5- and 10-min). Five metrics of resting HRV [mean interbeat interval (IBI), the standard deviation of normal IBIs (SDNN), root square mean of successive differences between IBIs (RMSSD), cardiac vagal index (CVI), and cardiac sympathetic index (CSI)] were assessed in 421 twin pairs aged 14-20 during a baseline electrocardiogram. This was done for four successive 2.5-min intervals as well as the overall 10-min interval. Heritability (h2) appeared consistent across intervals within each metric with the following estimates (collapsed across time intervals): mean IBI (h2 = 0.36-0.46), SDNN (h2 = 0.23-0.30), RMSSD (h2 = 0.36-0.39), CVI (h2 = 0.37-0.42), CSI (h2 = 0.33-0.46). Beyond additive genetic contributions, unique environment also was an important influence on HRV. Within each metric, a multivariate Cholesky decomposition further revealed evidence of genetic stability across the four successive 2.5-min intervals. The same models showed evidence for both genetic and environmental stability with some environmental attenuation and innovation. All measures of HRV were moderately heritable across time, with further analyses revealing consistent patterns of genetic and environmental influences over time. This study confirms that in an adolescent sample, the time interval used (2.5- vs. 10-min) to measure HRV time domain metrics does not affect the relative proportions of genetic and environmental influences.

First-degree atrioventricular block on basal electrocardiogram predicts future arrhythmic events in patients with Brugada syndrome: a long-term follow-up study from the Veneto region of Northeastern Italy.

This study was designed to assess the prognostic value of clinical and electrocardiographic parameters in Brugada syndrome (BrS). The study population included 272 consecutive patients (82% males; mean age 43 ± 12 years), with either a spontaneous (n = 137, 50%) or drug-induced (n = 135, 50%) Type 1 Brugada electrocardiogram (ECG) pattern. The study combined endpoint included sudden cardiac death (SCD), cardiac arrest, and appropriate intervention of implantable cardioverter-defibrillator (ICD). A first-degree atrioventricular (AV) block (PR = 219 ± 17 ms) was documented at basal ECG in 45 patients (16.5%); 27 of these underwent an electrophysiological study with recording in 21 (78%) of an HV interval ≥55 ms (mean 61 ± 3 ms). Patients with first-degree AV block had a wider QRS complex (median 110 ms vs. 95 ms; P = 0.04) and more often showed a left anterior hemiblock pattern (n = 13, 29% vs. n = 35, 16%; P = 0.056). During a mean follow-up of 85 ± 55 months, 17 patients (6.3%) experienced ≥1 major arrhythmic events (appropriate ICD intervention, n = 13 and SCD, n = 4). At univariate analysis, the occurrence of major arrhythmic events was significantly associated with a history of syncope or cardiac arrest (P < 0.001), Type 1 ECG pattern (P = 0.04), and first-degree AV block (P < 0.001). Univariate and multivariable predictors of events included a history of syncope or cardiac arrest [hazard ratio (HR) 5.8, 95% confidence interval (95% CI) 2.04-16.5; P < 0.001; and HR 6.68, 95% CI 2.34-19.1; P < 0.001; respectively], a spontaneous Type 1 ECG pattern (HR 1.56, 95% CI 1.03-4.24; P = 0.033; and HR 1.84, 95% CI 1.01-4.29; P = 0.044; respectively) and a first-degree AV block at baseline ECG (HR 3.84, 95% CI 1.47-9.99; P = 0.006; and HR 4.65, 95% CI 2.34-19.1; P = 0.002; respectively). Besides a history of cardiac arrest or syncope, first-degree AV block on basal ECG is an independent predictor of malignant arrhythmic events and a stronger marker of arrhythmic risk than a spontaneous 'coved-type' ECG pattern in patients with BrS.