Baseline Electrocardiogram Research Articles

Clinical, electrocardiographic and echocardiographic evolution of chronic Chagas disease treated with nifurtimox on prolonged follow‐up in Chile: observational study

This study aimed to describe the electrocardiographic and echocardiographic status of chronic Chagas disease (cChD) patients treated with nifurtimox. An observational study was performed in 146 cChD patients followed over a mean of 7.9 years. Of the 146 patients, 41 (28.1%) with normal electrocardiogram (ECG) at baseline maintained this condition, 34 (23.3%) with altered ECG at baseline normalised the alterations, and 46 (31.5%) with ECG abnormalities at baseline maintained this condition [23 (15.8%) with small alterations]. Finally, 25 cases (17.1%) in indeterminate phase altered the ECG. Differences before and after follow-up (P < 0.001) were found. The percentage of beneficial treatment was different than expected by chance (Z=4.8; P < 0.001) and the annual percentage of cases that developed ECG alterations was lower than that of a historical cohort of untreated patients (P < 0.001). An echocardiogram was performed in 68 patients with baseline ECG alterations. The ejection fraction (EF) was normal in 57 (83.8%) and abnormal in 11 (16.2%). In 38 patients with ECG abnormalities that did not progress after treatment, EF and segmental motility (SM) were normal in 31 (81.6%) and 26 (68.4%), respectively. In 17 patients with ECG abnormalities, EF and SM were normal in 15 (88.2%) and 14 (82.4%) cases, respectively. Less progression to cardiomyopathy compared with a historical untreated cohort as well as the EF/SM results in patients with abnormal ECG that did not progress and in indeterminate cChD that altered the ECG suggests a beneficial effect of nifurtimox.

Safety of Hydroxychloroquine use for COVID-19 prophylaxis: A questionnaire-based pilot study in healthcare professionals

Hydroxychloroquine (HCQ) was recommended for prophylaxis against SARS-COV-2 for the health care professionals by the Indian Council for Medical Research. We conducted this study to explore the safety of Hydroxychloroquine in health care professionals. A validated questionnaire was circulated electronically to the health care professionals, who were on HCQ as per ICMR recommended regimen. Questions on specific adverse drug reactions (ADRs) were asked along with other details. The participants were requested to upload the baseline and additional electrocardiograms (ECGs) taken during HCQ prophylaxis. Incidence, severity, causality (relatedness to the drug), expectedness, and seriousness of the ADRs were determined as per the standard guidelines. The ECGs were evaluated for the appearance of significant changes. The observations were analyzed through descriptive statistics. The ECG changes were compared using the Students t-test and the association of risk factors with the ADRs was evaluated using logistic regression analysis. ADRs were observed in 58 (46 %) of 126 participants. Gastrointestinal symptoms followed by headache and skin rashes were commonly observed. The ADRs were mostly mild to moderate in the category, non-serious, and possibly related to HCQ. Significant ECG changes were rare. Diabetes, hypertension, and the use of concomitant medication/s were the risk factors. Except for blurred vision, all the ADRs were unexpected in terms of frequency. HCQ causes non-specific ADRs of mild to moderate degrees when used as prophylaxis. Though non-serious, almost all were unexpected. ECG changes are probably not frequent in the absence of a pre-existing disease.

Association between fragmented QRS and postprocedural rhythm disturbances in patients who underwent transcatheter aortic valve implantation.

According to recent studies, the rate of atrioventricular block requiring permanent pacing in patients following transcatheter aortic valve implantation varied between 5.7% and 42.5%. Fragmented QRS is a useful marker of myocardial scar and can predict adverse cardiac events. In this study, we examined association between f ragmented QRS and postprocedural rhythm disturbances and the need for permanent pacing in patients who underwent transcatheter aortic valve implantation. In this study, we examined association between fragmented QRS and postprocedural rhythm disturbances and the need for permanent pacing in patients who underwent transcatheter aortic valve implantation' sentence is enough for it. We retrospectively analyzed standard 12-lead electrocardiographic recordings of 124 consecutive patients in whom a CoreValve prosthesis was implanted. We examined 12-lead electrocardiogram before and after procedure along with one- and six-month follow-up. We documented QRS fragmentation and postprocedural rhythm disturbances. There was a significant increase in the frequency of left bundle branch block, (21.1 versus 0%, p<0.05) and the incidence of atrioventricular blocks requiring permanent pacing (21.1 versus 0%, p<0.05) following transcatheter aortic valve implantation in patients whose preprocedural electrocardiogram recordings revealed fragmented QRS compared to those without fragmented QRS. Based our collected data, the presence of QRS fragmentation in anterior derivations was the only independent factor associated with postprocedural rhythm disturbances (B-value 0.217; OR 0.805; 95%CI 0.136-4.78; p=0.004). Our data showed an increased risk for the development of new-onset left bundle branch block and atrioventricular blocks following transcatheter aortic valve implantation in patients whose baseline electrocardiogram recordings demonstrated QRS fragmentation.

Potential role of an athlete-focused echocardiogram in sports eligibility.

Sudden cardiac death (SCD) of an athlete is a rare but tragic event and sport activity might play a trigger role in athletes with underlying structural or electrical heart diseases. Preparticipation screenings (PPs) have been conceived for the potential to prevent SCD in young athletes by early identification of cardiac diseases. The European Society of Cardiology protocol for PPs includes history collection, physical examination and baseline electrocardiogram, while further examinations are reserved to individuals with abnormalities at first-line evaluation. Nevertheless, transthoracic echocardiography has been hypothesized to have a primary role in the PPs. This review aims to describe how to approach an athlete-focused echocardiogram, highlighting what is crucial to focus on for the different diseases (cardiomyopathies, valvulopathies, congenital heart disease, myocarditis and pericarditis) and when is needed to pay attention to overlap diagnostic zone (“grey zone”) with the athlete's heart. Once properly tested, focused echocardiography by sports medicine physicians may become standard practice in larger screening practices, potentially available during first-line evaluation.

Cardiac magnetic resonance imaging in right ventricular outflow tract arrhythmia: a retrospective analysis from a tertiary care centre in South India

Introduction Arrhythmia arising from right ventricular outflow tract (RVOT) is the most common cause of idiopathic ventricular arrhythmia. Previous studies involving cardiac magnetic resonance imaging (MRI) in these patients are known to show abnormalities in up to 60% of patients. Methodology This was a retrospective descriptive analysis of patients having idiopathic RVOT arrhythmia who underwent cardiac MRI between January 2010 and December 2020. Clinical and demographic details were recorded from the electronic medical records and cardiac MRI of all patients were reviewed. Results Among 214 patients with RVOT arrhythmia, 64 underwent cardiac MRI. A total of 41 patients, who did not have any abnormality on baseline echocardiogram were included in the study. There was male preponderance (56.1%), with median age of 43 years. About 43.9% had syncope. Twenty-four-hour Holter study revealed a premature ventricular complex (PVC) burden of 26.3 ± 11.7%. MRI showed structural abnormalities in 51.2% of patients, which commonly included RV sacculations and aneurysms. Late gadolinium enhancement (LGE) was seen in six patients, which was mostly seen in RV free wall. Right ventricular (RV) systolic dysfunction was evident in 29.3%. About 9.8% fulfilled the criteria for arrhythmogenic RV cardiomyopathy (ARVC). Out of 23 patients with baseline abnormalities on ECHO, 87% had structural abnormalities on MRI, and 43.5% fulfilled the criteria for ARVC. Conclusions Additional imaging by cardiac MRI helps to identify structural abnormalities in 51.2% of patients with RVOT arrhythmias, even with normal baseline echocardiogram and electrocardiogram (ECG). It is useful tool to rule out ARVC in this subset of patients, and can help in increasing the diagnostic yield in the early stages.

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.

Electrocardiographic Patterns in Patients with Neurally Mediated Syncope.

The baseline electrocardiogram (ECG) is less informative in neurally mediated syncope (NMS) than in arrhythmic syncope. However, some of the ECG patterns present in NMS can have diagnostic and prognostic value in such patients. Electrocardiographic documentation of a syncopal spell and thus identification of the ECG changes can be performed during tilt table test (TTT) or during prolonged ECG monitoring. This work reviews the specific ECG patterns in NMS, which are primarily related to the cardioinhibitory reflex. In addition, there are other ECG findings present in patients with NMS that are being analyzed, such as increased heart rate variability as well as specific QRS voltage patterns. In addition to the diagnostic and prognostic value, these ECG patterns in NMS may help improving the selection of patients for pacemaker implant.

Lessons Learned During the Pandemic: Correlation of QT Intervals Between Telemetry and 12-Lead Electrocardiogram.

Background and objectiveQT prolongation is associated with an increased risk of ventricular arrhythmias. Since some patients on contact or droplet precautions require QT-prolonging medications, monitoring the QT interval may become imperative to prevent fatal arrhythmias. To limit the exposure of staff to patients during and even after the coronavirus disease 2019 (COVID-19) pandemic and judiciously use personal protective equipment (PPE), it is important to find alternatives to frequent 12-lead electrocardiograms (ECG). The objective of this study was to compare QT intervals measured on telemetry to those measured on 12-lead ECG to determine whether telemetry QT interval measurements could be used in place of 12-lead measurements.MethodsSimultaneous telemetry recordings via a Philips telemetry monitoring system (Philips Healthcare, Eindhoven, Netherlands) and 12-lead ECGs were obtained from 50 patients. Patients were from cardiac telemetry and cardiac intensive care units. QT interval from the telemetry system was compared to the QT interval on the 12-lead ECG. QT intervals on two telemetry strips were uninterpretable as the termination of the T-wave could not be defined appropriately; therefore, these patients were excluded.ResultsIn 33 of 48 patients (69%), QT intervals from the telemetry studies matched the QT intervals measured by 12-lead ECG. The intraclass correlation coefficient (ICC) between telemetry QT and 12-lead ECG QT was 0.887 (95% CI: 0.809-0.934; p<0.001). In 15 of 48 patients (31%), the QT intervals measured from telemetry were different from those measured by 12-lead ECG. These patients either had an abnormal rhythm, conduction abnormalities, or repolarization abnormalities at baseline.ConclusionTelemetry is a suitable alternative for measuring QT intervals in the majority of patients. However, those with baseline ECG abnormalities should have serial 12-lead ECGs. This can reduce the risk of staff exposure to pathogens and prevent overuse of PPE during the COVID-19 pandemic and for other patients in isolation.

B-PO02-152 ELECTROCARDIOGRAPHIC CHANGES IN A DOUBLE-BLIND, PLACEBO-CONTROLLED RANDOMIZED TRIAL OF ETHANOL VERSUS PLACEBO

Alcohol is implicated as a common trigger for discrete atrial fibrillation (AF) episodes, but the mechanism by which this occurs remains unknown. Changes in the 12-lead surface electrocardiogram (ECG) can reflect aberrations in conduction time (changes in P wave and QRS durations), autonomic tone (PR interval) and refractoriness (QT interval). We sought to compare ECG changes between two groups randomly assigned to intravenous alcohol versus placebo. To determine the effect of acute ethanol exposure on 12-lead ECGs in human subjects. We performed a secondary analysis of the HOLIDAY (How Alcohol Induces Atrial Tachyarrhythmias) randomized trial. Briefly, 100 participants in sinus rhythm undergoing ablation procedures for AF were randomly assigned to intravenous ethanol titrated to 0.08% blood alcohol concentration versus double-blind, osmotic and volume equivalent placebo infusion. Pre versus post-infusion P wave, PR, QRS, and QT durations were assessed. No significant differences in baseline ECG intervals between ethanol versus placebo groups were observed. Participants receiving the ethanol infusion exhibited a trend towards an increased P wave duration (3.89 ms ± 13.09, p = 0.055), a lengthening in the QRS (3.14 ± 10.06, p = 0.045), and an increase in the PR interval (5.25 ms ± 15.05, p = 0.026), while none of these measurements meaningfully changed in the placebo group. The QTc increased significantly in both the alcohol and control groups (21.55 ms ± 27.37, p <0.001 and 15.52 ms ± 27.50, p <0.001). Acute exposure to ethanol resulted in an increase in the PR interval, potentially reflecting an increase in vagal tone, accompanied by a trend towards a longer P wave duration and a significant lengthening of the QRS interval, indicative of conduction slowing. These data suggest that autonomic changes and changes in conduction velocity may play important in roles in the initiation of alcohol-related AF.

The impact of hydroxychloroquine and azithromycin on the corrected qt interval in patients with the novel Coronavirus disease 2019.

With the coronavirus disease 2019 (COVID-19) continuing to spread all over the world, although there is no specific treatment until now, hydroxychloroquine and azithromycin have been reported to be effective in recent studies. Although long-term use of hydroxychloroquine and azithromycin has been reported to cause QT prolongation and malign arrhythmia, there is not enough data about the effect of short-term use on arrhythmia. Therefore, this study aims to assess the effect of hydroxychloroquine alone and hydroxychloroquine + azithromycin on corrected QT (QTc). A baseline electrocardiogram and on-treatment baseline electrocardiogram were retrospectively collected in COVID-19 patients who received hydroxychloroquine and/or azithromycin. The QTc interval was calculated, and the baseline and peak QTc intervals were compared. In addition, the peak QTc intervals of monotherapy and combination therapy were compared. Of the 155 patients included, 102 (65.8%) patients were using hydroxychloroquine, and 53 (34.2%) patients were using hydroxychloroquine + azithromycin combination. The use of both hydroxychloroquine alone and hydroxychloroquine + azithromycin combined therapy significantly prolonged the QTc, and the QTc interval was significantly longer in patients receiving combination therapy. QTc prolongation caused early termination in both groups, 5 (4.9%) patients in the monotherapy group and 6 (11.3%) patients in the combination therapy group. In this study, patients who received hydroxychloroquine for the treatment of COVID-19 were at high risk of QTc prolongation, and concurrent treatment with azithromycin was associated with greater changes in QTc.

Angiotensin-converting Enzyme Inhibitors: Can it be a Potential Treatment of Infantile Hemangioma.

Aims:The aim of the sudy was to evaluate potential role of oral captopril, an angiotensin-converting enzyme (ACE) inhibitor, and in treatment of infantile hemagioma (IH) and report our preliminary results.Methods:This prospective study included 18 children with IH admitted in the department of pediatric surgery with no history of prior treatment of any type. Baseline blood pressure (BP), electrocardiogram, two-dimensional echocardiography, serum electrolytes, and renal function test (RFT) were noted. Oral captopril was started as first-line drug at a dose of 0.1 mg/kg orally 12 h with gradually increase of dosage up to 2.0 mg/kg 12 h over the period of 10 days with monitoring of BP, serum electrolytes, RFT, and occurrence of any side effect. If no side effects were noted and patients were stable, they were discharged and followed up until 6 months after stopping treatment. During follow-up, response to treatment was documented clinically and photographically. Development of any side effect was also noted.Results:Excellent response to captopril was noticed in nine patients over 16–18 months. Four patients showed good response. Oral propranolol had to be administered alternatively in one patient showing fair response during the initial 4 months but no response afterward and in four patients showing no response at all. One patient developed an allergic reaction to propranolol and was started oral corticosteroid. These five patients had near complete resolution of lesion for the next 8–10 months.Conclusions:ACE inhibitors might have a role, though slow, in the involution of IHs. Therefore, these may have the potential to emerge as an alternative treatment for IH in future after confirmation with randomized studies with propranolol.

Physical health audit of gwent specialist substance misuse services (North Team)

Physical health audit of gwent specialist substance misuse services (North Team)

Screening for atrial fibrillation in hypertensive patients using a mobile application (about 160 cases)

Atrial fibrillation (AF) is the most common cardiac arrhythmia, affecting between 1 and 4% of the general population and responsible for 10 to 20% of strokes. New technologies are now available for screening for AF, but their implementation in real clinical settings has not yet been fully investigated. The aim of our study is to evaluate the electrocardiogram (ECG) recordings on smartphones intended for screening for AF using the KardiaMobile device (Alivecor), a portable device 5 cm long and 80 g in weight, with a dedicated mobile application. Prospective screening for AF in patients aged 55 or over, known to be hypertensive for at least 5 years, was performed at the cardiology consultation services between June 2019 and July 2020. exclusion from the study. The CHA2DS2-VASc score was collected from each patient. A single lead ECG was acquired by placing the fingers of each hand on the electrodes. The diagnosis of the Kardia app was assessed by the consultation cardiologist, and a baseline ECG was performed for each suspected arrhythmia. A total of 160 ECGs were performed. The diagnosis of the Kardia app was provided in 93% of cases. A heart rhythm described as normal was detected in 120 consultants, in an atrial fibrillation was suspected in 8.1% of the patients described by the device as possible AF, and confirmed by a baseline ECG in 7.5% of the patients screened ( Fig. 1 ). Anti-coagulation was started in 6.2% of patients based on the CHADS-VASC score. The Kardia app is able to quickly filter and detect AF with high sensitivity and specificity. The possible diagnosis of possible AF warrants further cardiological evaluation screening through the use of mHealth technology could be an effective tool in patients at cardiovascular risk for better prevention.

Bundle branch block is your friend for pathway localization

A 49-year-old healthy woman presented with a narrow, regular complex, short RP tachycardia. Her baseline electrocardiogram showed ventricular pre-excitation (Supplemental Figure 1). How do the data shown in Figure 1 help in localizing the AP?

Implantable loop recorder: experience of a center

Abstract Funding Acknowledgements Type of funding sources: None. INTRODUCTION Symptoms like syncope and palpitations are frequent and represent a diagnostic challenge. The implantable loop recorder (LR) is an important diagnostic tool, in selected cases. AIM To describe the main implantation indications of LR and to evaluate the diagnostic findings and therapeutic interventions. METHODS A retrospective study of patients (pts) that underwent LR implantation in our hospital from 2014 to 2019. For each pt the indication for implantation, baseline characteristics, previous study, recorded tracing and interventions were evaluated. RESULTS A total of 52 pts were included, 56% women, with a mean age of 60 years old. The implantation indications were recurrent syncope/ presyncope in 47 pts (90%) and palpitations in 5 pts (10%). All pts had a baseline echocardiogram and electrocardiogram, with 90% in sinus rhythm. QRS complex and atrial-ventricular conduction was normal in 50% of the pts. Previous to LR implantation, 46 pts (89%) had performed Holter, 19 (37%) carotid sinus massage, 14 (27%) Tilt table test, 29 (56%) stress test, 11(21%) ambulatory blood pressure monitoring and 9 (17%) electrophysiological study. During the monitoring period, 27 pts (52%) had recurrence of the symptoms. In this subgroup, we observed that 67% had a rhythmic cause capable of justified the symptoms, with a median of 5 months since implantation until diagnosis. In addition, the LR was useful in ruling out a rhythmic cause for symptoms in 33% of the cases. In the 47 pts with syncope/presyncope: 6(13%) had sinus node dysfunction, 4 (9%) had atrioventricular conduction disturbance, 1(2%) had atrial fibrillation (AF) and 3 (6%) had ventricular dysrhythmias. In the 5 pts with palpitations: 1(20%) had AF ad 3 (60%) had paroxysmal supraventricular tachycardia. LR results led to cardiac device implantation in 13 pts (pacemaker-9, implantable cardioverter desfibrillator-4). In addition, 2 pts are waiting for electrophysiological study and eventual ablation and 3 pts initiated antiarrhythmic therapy, and those with new diagnosis of AF also initiated oral anticoagulants. CONCLUSION In this study, the implantation of LR was useful to clarify the cause of the symptomology in 52% of the pts. In 35% of pts with symptom-rhythm correlation it ensured timely introduction of therapeutic approach with a positive impact on life quality.

The role of the electrocardiographic phenotype in risk stratification for sudden cardiac death in childhood hypertrophic cardiomyopathy.

AimsThe 12-lead electrocardiogram (ECG) is routinely performed in children with hypertrophic cardiomyopathy (HCM). An ECG risk score has been suggested as a useful tool for risk stratification, but this has not been independently validated. This aim of this study was to describe the ECG phenotype of childhood HCM in a large, international, multi-centre cohort and investigate its role in risk prediction for arrhythmic events.Methods and resultsData from 356 childhood HCM patients with a mean age of 10.1 years (±4.5) were collected from a retrospective, multi-centre international cohort. Three hundred and forty-seven (97.5%) patients had ECG abnormalities at baseline, most commonly repolarization abnormalities (n = 277, 77.8%); left ventricular hypertrophy (n = 240, 67.7%); abnormal QRS axis (n = 126, 35.4%); or QT prolongation (n = 131, 36.8%). Over a median follow-up of 3.9 years (interquartile range 2.0–7.7), 25 (7%) had an arrhythmic event, with an overall annual event rate of 1.38 (95% CI 0.93–2.04). No ECG variables were associated with 5-year arrhythmic event on univariable or multivariable analysis. The ECG risk score threshold of >5 had modest discriminatory ability [C-index 0.60 (95% CI 0.484–0.715)], with corresponding negative and positive predictive values of 96.7% and 6.7%ConclusionIn a large, international, multi-centre cohort of childhood HCM, ECG abnormalities were common and varied. No ECG characteristic, either in isolation or combined in the previously described ECG risk score, was associated with 5-year sudden cardiac death risk. This suggests that the role of baseline ECG phenotype in improving risk stratification in childhood HCM is limited.

Effect of methadone on QTc in infants

ObjectiveMethadone has been associated with prolongation of the QTc interval (QTc) on electrocardiogram (ECG). In infants, the effects of methadone on the QTc are not well described. Our study's objective is to evaluate the QTc in infants being treated with methadone. MethodsWe conducted a retrospective study in infants receiving methadone. We collected demographic data, methadone dose, and QTc. A blinded-to-disease-state pediatric electrophysiologist determined the QTc. Baseline ECG was defined as an ECG obtained while not on methadone therapy, and QTc on baseline ECG was compared with treatment QTc. A significant change was defined as any absolute QTc greater than 500 or a QTc greater than 460 with an increase from baseline of greater than 40 ms. ResultsA total of 44 infants comprised the study population. The mean gestational age was 32.3 ± 5.51 weeks. The median age of initiation was 66 days. The median dose was 0.52 mg/kg/day in oral methadone equivalents. Nine patients were on high dose methadone (>1 mg/kg/day in oral methadone equivalents). The mean baseline QTc was 421 ± 27 and the mean change on methadone was −2 ms. No patient had a QTc greater than 500 on methadone. One patient had a QTc of 467 and 46 ms change from baseline, with no clinically significant impact. ConclusionIn our study population, methadone did not significantly prolong the QTc. Further prospective study is warranted to determine the utility and frequency of ECGs in infants receiving methadone.

Diagnostic accuracy of the response to the brief tachycardia provoked by standing in children suspected for long QT syndrome.

BackgroundAdult long QT syndrome (LQTS) patients have inadequate corrected QT interval (QTc) shortening and an abnormal T-wave response to the sudden heart rate acceleration provoked by standing. In adults, this knowledge can be used to aid an LQTS diagnosis and, possibly, for risk stratification. However, data on the diagnostic value of the standing test in children are currently limited.ObjectiveTo determine the potential value of the standing test to aid LQTS diagnostics in children.MethodsIn a prospective cohort including children (≤18 years) who had a standing test, comprehensive analyses were performed including manual and automated QT interval assessments and determination of T-wave morphology changes.ResultsWe included 47 LQTS children and 86 control children. At baseline, the QTc that identified LQTS children with a 90% sensitivity was 435 ms, which yielded a 65% specificity. A QTc ≥ 490 ms after standing only slightly increased sensitivity (91%, 95% confidence interval [CI]: 80%–98%) and slightly decreased specificity (58%, 95% CI: 47%–70%). Sensitivity increased slightly more when T-wave abnormalities were present (94%, 95% CI: 82%–99%; specificity 53%, 95% CI: 42%–65%). When a baseline QTc ≥ 440 ms was accompanied by a QTc ≥ 490 ms and T-wave abnormalities after standing, sensitivity further increased (96%, 95% CI: 85%–99%) at the expense of a further specificity decrease (41%, 95% CI: 30%–52%). Beat-to-beat analysis showed that 30 seconds after standing, LQTS children had a greater increase in heart rate compared to controls, which was more evidently present in LQTS boys and LQTS type 1 children.ConclusionIn children, the standing test has limited additive diagnostic value for LQTS over a baseline electrocardiogram, while T-wave abnormalities after standing also have limited additional value. The standing test for LQTS should only be used with caution in children.

Atrioventricular block after COVID-19: What is the mechanism, site of block, and treatment?

A 49-year-old healthy woman presented with exertional shortness of breath and palpitations of 3 months’ duration. Baseline electrocardiogram (ECG) was normal. Figure 1 shows selected tracings recorded during treadmill stress testing. Transthoracic echocardiogram showed no structural abnormalities. Cardiac positron emission tomogram showed normal myocardial perfusion and no abnormal fluorodeoxyglucose uptake. Antibody titers for Lyme disease were undetectable. Figure 2 shows selected tracings from an invasive electrophysiological (EP) study.

Case Report: Takotsubo Syndrome Associated With Novel Coronavirus Disease 2019

Background: Takotsubo cardiomyopathy is triggered by emotional or physical stress. It is defined as a reversible myocardial dysfunction, usually with apical ballooning aspect due to apical akinesia associated with hyperkinetic basal left ventricular contraction. Described in cases of viral infections such as influenza, only few have been reported associated with novel coronavirus disease 2019 (COVID-19) in the recent pandemic.Case summary: A 79-years-old man, with cardiovascular risk factors (type 2 diabetes and hypertension) and chronic kidney disease, presented to the emergency room for severe dyspnea after 8 days of presenting respiratory symptoms and fever. Baseline electrocardiogram (ECG) was normal, but he presented marked inflammatory syndrome. He was transferred to an intensive care unit to receive mechanical ventilation within 6 h, due to acute respiratory distress syndrome. He presented circulatory failure 2 days after, requiring norepinephrine support (up to up to 1.04 μg/kg/min). Troponin T was elevated (637 ng/l). ECG showed diffuse T wave inversion. Echocardiography showed reduced left ventricular ejection fraction (LVEF 40%), with visual signs of Takotsubo cardiomyopathy. Cardiac failure resolved after 24 h with troponin T decrease (433 ng/l) and restoration of cardiac function (LVEF 60% with regression of Takotsubo features). Patient died after 15 days of ICU admission, due to septic shock from ventilator-acquired pneumonia. Cardiac function was then normal.Conclusion: Mechanisms of Takotsubo cardiomyopathy in viral infections include catecholamine-induced myocardial toxicity and inflammation related to sepsis. Differential diagnoses include myocarditis and myocardial infarction. Evidence of the benefit of immunomodulatory drugs and dexamethasone are growing to support this hypothesis in COVID-19.