Clinical valuation of ST changes in a group of patients with ventricular arrhythmias: The inSighT Study.

BACKGROUND: The inSighT study was designed to determine the prevalence of ischemic changes as recorded by implantable cardioverter-defibrillator (ICD) ST deviations in intracardiac electrocardiograms (EGM) over the 24 h preceding malignant ventricular arrhythmias (VT/VF). METHODS: The study enrolled patients with known coronary artery disease (CAD) or high risk of future development of CAD implanted with an ICD equipped with an ST monitoring feature (Ellipse™/Fortify Assura™, St. Jude Medical). Device session records were collected at each in-clinic follow-up. EGM ST levels of the beats over the 15 minutes prior to VT/VF events were compared using a t test with those from a baseline period of 23-24 h prior to the VT/VF event. All events with p < .05 were visually inspected to confirm they were evaluable; additional criteria for exclusion from further analysis included inappropriate therapy, aberrant conduction, and occurrence of VT/VF within 24h prior to the current event. RESULTS: The study enrolled 481 ICD patients (64 ± 11 years, 83% male) in 14 countries and followed them for 15±5 months. A total of 165 confirmed VT/VF episodes were observed, of which 71 events (in 56 patients, 34% of all patients with VT/VF) were preceded by significant (p < .05) ST-segment changes unrelated to known non-ischemic causes. None of the analyzed demographic and clinical factors proved to be associated with greater odds of presenting with ST-segment changes prior to VT/VF episode. CONCLUSION: In this exploratory study, characteristic ST-segment changes, likely representative of ischemic events, were observed in 34% of all patients with VT/VF episodes.

2021 ISHNE/ HRS/ EHRA/ APHRS collaborative statement on mHealth in Arrhythmia Management: Digital Medical Tools for Heart Rhythm Professionals: From the International Society for Holter and Noninvasive Electrocardiology/Heart Rhythm Society/European Heart Rhythm Association/Asia Pacific Heart Rhythm Society.

This collaborative statement from the International Society for Holter and Noninvasive Electrocardiology/ Heart Rhythm Society/ European Heart Rhythm Association/ Asia Pacific Heart Rhythm Society describes the current status of mobile health ("mHealth") technologies in arrhythmia management. The range of digital medical tools and heart rhythm disorders that they may be applied to and clinical decisions that may be enabled are discussed. The facilitation of comorbidity and lifestyle management (increasingly recognized to play a role in heart rhythm disorders) and patient self-management are novel aspects of mHealth. The promises of predictive analytics but also operational challenges in embedding mHealth into routine clinical care are explored.

Baseline intrinsic heart rate and response to ivabradine treatment in patients with inappropriate sinus tachycardia.

BACKGROUND: Treatment with ivabradine became a new therapeutic alternative for patients with inappropriate sinus tachycardia (IST). The aim was to determine a relation between intrinsic heart rate (IHR) and response to ivabradine treatment. METHODS: Twenty-seven patients (mean age 37 ± 11; 23 women) with symptomatic IST despite medical treatment were recruited into the study. Resting ECG, 24-hr ECG monitoring (24hECG), exercise treadmill test, and symptoms evaluation were performed initially and after 60 days on ivabradine. IHR was acquired at baseline after pharmacological autonomic blockade. RESULTS: Nineteen patients (70%) were classified as abnormal IHR group (AIHR) while eight showed normal IHR (NIHR). No significant differences in ECG parameters were found between NIHR and AIHR subgroups, while baseline exercise capacity was higher in AIHR patients (10.9 vs. 9.5 METs, p < .05). Ivabradine treatment resulted in significant reduction in resting heart rate, average 24hECG heart rate, improvement in exercise capacity and reduction of symptoms in both subgroups. Nevertheless, favorable influence of ivabradine was significantly more exaggerated in AIHR subgroup (HR 116 vs. 90 bpm, av. HR 98 vs. 79 bpm, 10.9 vs. 13.6 METS, EHRA score 3.1 vs. 1.1, p < .001 for all) than in NIHR patients (HR 112 vs. 98 bpm, av. HR 97 vs. 88 bpm, 9.5 vs. 11.1 METs, EHRA score 3.1 vs. 1.9; p < .05 for all). CONCLUSIONS: Intrinsic heart rate may be useful in predicting response to ivabradine in patients with IST. More intense response to ivabradine in patients with AIHR may be attributed to different pathophysiological mechanisms underlying IST in AIHR and NIHR groups.

A counterpoint paper: Comments on the electrocardiographic part of the 2018 Fourth Universal Definition of Myocardial Infarction endorsed by the International Society of Electrocardiology and the International Society for Holter and Noninvasive Electrocardiology.

The Fourth Universal Definition of Myocardial Infarction (FUDMI) focuses on the distinction between nonischemic myocardial injury and myocardial infarction (MI), along with the role of cardiovascular magnetic resonance, in order to define the etiology of myocardial injury. As a consequence, there is less emphasis on updating the parts of the definition concerning the electrocardiographic (ECG) changes related to MI. Evidence of myocardial ischemia is a prerequisite for the diagnosis of MI, and the ECG is the main available tool for (a) detecting acute ischemia, (b) triage, and (c) risk stratification upon presentation. This review focuses on multiple aspects of ECG interpretation that we firmly believe should be considered for incorporation in any future update to the Universal Definition of MI.

Conventional and alternative preimplantation ECG screening for subcutaneous ICD in high risk hypertrophic cardiomyopathy patients.

INTRODUCTION: Patients with hypertrophic cardiomyopathy (HCM) relatively often fail preimplantation ECG screening for subcutaneous implantable cardioverter-defibrillator (S-ICD). We aimed to evaluate impact of conventional and alternative ECG electrodes placement on eligibility for S-ICD implantation in HCM patients at high risk of sudden cardiac death (SCD). We hypothesized that modified electrodes placement will influence QRS-T morphology and thus it will increase S-ICD eligibility in the screening process. MATERIAL AND METHODS: This study enrolled 17 HCM patients at high risk of SCD (5-year SCD risk above 5%) referred for an ICD implantation. ECG screening for S-ICD eligibility in horizontal and vertical position was performed in each patient, in two different screening electrodes configuration: conventional (recommended by manufacturer) and alternative (precordial electrodes shifted rightwards and lateral electrodes dorsally). We evaluated QRS and T waves amplitude as well as T wave index. Primary, secondary and alternate sensing vectors were assessed. RESULTS: Preimplantation ECG screening with alternative electrodes placement resulted in more sensing vectors that were screened successfully (77 vs. 88, p = 0.05). Modified screening combined with a standard one allowed more patients to qualify for S-ICD implantation (17/17 vs. 12/17, p = 0.04). Electrocardiographically, the alternative positioning of ECG electrodes resulted in significant decrease in absolute values of QRS complex and T waves amplitudes in almost all sensing vectors, which was responsible for successful screening. CONCLUSIONS: The use of alternative placement of screening electrodes may be a valuable method to increase eligibility for S-ICD implantation in HCM patients at high risk of SCD.

A counterpoint paper: Comments on the electrocardiographic part of the 2018 Fourth Universal Definition of Myocardial Infarction.

The Fourth Universal Definition of Myocardial Infarction (FUDMI) [published simultaneously in 2018 in numerous journals including Circulation, Journal of the American College of Cardiology and European Heart Journal] focuses mainly on the distinction between non-ischemic myocardial injury and myocardial infarction (MI), along with the role of cardiovascular magnetic resonance, in order to define the etiology of myocardial injury. As a consequence, there is less emphasis on updating the parts of the definition concerning the electrocardiographic (ECG) changes related to MI. Evidence of myocardial ischemia is a prerequisite for the diagnosis of MI and the ECG is the main available tool for i) detecting acute ischemia, ii) triage and iii) risk stratification upon presentation. This review focuses on multiple aspects of ECG interpretation that we firmly believe should be considered for incorporation in any future update to the Universal Definition of MI. Our counterpoint view is that: a) the use of the ECG following coronary artery bypass surgery should be better explored and defined; b) the emphasis in the FUDMI on convex versus concave ST-elevation, which is questionable, should be balanced by the fact that many patients with true ST-elevation MI (STEMI) present with a concave form of ST elevation; c) reciprocal ST-depression in STEMI caused by right coronary artery or left circumflex artery occlusion, should be set against the fact that not all anterior STEMIs present with reciprocal ST-depression which can also be seen in cardiomyopathy and left ventricular hypertrophy; d) the "posterior" leads V7-V9 should be placed on a horizontal line from V4, rather than follow the 5th intercostal space; e) ST-depression in V1-V3 is not a manifestation of ischemia of the basal inferior segment, placed horizontally; f) Interpreting ST-T changes in patients with conduction abnormalities and pacemakers should be further defined.

[ECG abnormalities in athletes as compare to healthy subjects]. / Nieprawidlowosci w EKG u sportowców w porównaniu z grupa kontrolna.

Physical exercise promotes structural heart adaptation and increased parasympathetic autonomous activity in athletes. Some reports indicate that sinus bradycardia can promote occurrence of arrhythmias in athletes. AIM: The aim of this study was to compare the 12-lead surface ECG findings and arrhythmias/conduction disturbances detected in ambulatory ECG monitoring (AECG) between amateur athletes and healthy subject and to investigate relationship between bradycardia and arrhythmias. MATERIALS AND METHODS: Studied population included 34 athletes (29M, 5F, av. age 29±8yrs) and a control group of 34 healthy volunteers (29M, 5F, av. age 30±8yrs). 12-lead surface ECG and 24-hour AECG were performed in order to evaluate heart rate and arrhythmia/conduction disturbances in two groups. RESULTS: The athletes group was characterized by lower heart rate (med.59 vs.70 bpm, p<0.001), longer PR interval (med. 174 vs. 150 msec, p=0.007) and longer QTcF interval (med. 403 vs. 395 msec, p=0.026), with no statistically difference in QRS duration (med. 99 vs. 102 msec, p=0.699). Voltage criteria of LVH were observed in 10/34 (29%) of athletes and in 1 (2.94%) healthy subject. Four athletes (12%) showed first degree AV block. Similarly to ECG findings, AECG showed lower HR values (med. 66 vs.74 bpm, p<0.001) in athletes than in healthy subjects. Sinus bradycardia (<60bpm) was observed in 26% of athletes and 0% of controls (p=0.042). Ventricular arrhythmia was observed in 62% of athletes and 50% of healthy controls (p=0.464). No difference in occurrence of APBs was observed between studied groups (88% vs. 91%). Differences between occurrence of arrhythmias in athletes with lower HR (<60bpm) compared to those with higher did not reach statistical significance (VPBs: 6/9 vs. 15/25, p = 0.963; APBs: 9/9 vs 21/29, p = 0.5). CONCLUSIONS: Bradycardia does not promote ventricular neither atrial arrhythmias in athletes.

Severe atrial fibrosis as a cause of significant intraatrial conduction delay in a patient with scleromyositis.

Scleromyositis is an autoimmune disease and an overlap syndrome of scleroderma and poly/dermatomyositis. It is characterized by frequent cardiovascular involvement including heart failure, arrhythmias and conduction disturbances. We present a case of a 73-year old female patient who required an upgrade from a DDD pacemaker to cardiac resynchronization therapy due left ventricular dysfunction and permanent ventricular pacing. Electroanatomical mapping (CARTO 3D) revealed extensive right atrial fibrosis which resulted in significant delay in intraatrial conduction. Interval from atrial paced stimulus to A signal in His bundle was 364 ms, while AH and HV intervals were within normal range.

Present criteria for prophylactic ICD implantation: Insights from the EU-CERT-ICD (Comparative Effectiveness Research to Assess the Use of Primary ProphylacTic Implantable Cardioverter Defibrillators in EUrope) project.

BACKGROUND: The clinical effectiveness of primary prevention implantable cardioverter defibrillator (ICD) therapy is under debate. It is urgently needed to better identify patients who benefit from prophylactic ICD therapy. The EUropean Comparative Effectiveness Research to Assess the Use of Primary ProphylacTic Implantable Cardioverter Defibrillators (EU-CERT-ICD) completed in 2019 will assess this issue. SUMMARY: The EU-CERT-ICD is a prospective investigator-initiated non-randomized, controlled, multicenter observational cohort study done in 44 centers across 15 European countries. A total of 2327 patients with heart failure due to ischemic heart disease or dilated cardiomyopathy indicated for primary prophylactic ICD implantation were recruited between 2014 and 2018 (>1500 patients at first ICD implantation, >750 patients non-randomized non-ICD control group). The primary endpoint was all-cause mortality, and first appropriate shock was co-primary endpoint. At baseline, all patients underwent 12­lead ECG and Holter-ECG analysis using multiple advanced methods for risk stratification as well as documentation of clinical characteristics and laboratory values. The EU-CERT-ICD data will provide much needed information on the survival benefit of preventive ICD therapy and expand on previous prospective risk stratification studies which showed very good applicability of clinical parameters and advanced risk stratifiers in order to define patient subgroups with above or below average ICD benefit. CONCLUSION: The EU-CERT-ICD study will provide new and current data about effectiveness of primary prophylactic ICD implantation. The study also aims for improved risk stratification and patient selection using clinical risk markers in general, and advanced ECG risk markers in particular.

Repolarization abnormalities in carbon monoxide poisoning - a case report.

Each year a notable number of fatal intoxications with carbon monoxide (CO) is reported worldwide. Carbon monoxide binds with hemoglobin, decreases oxygen supply and leads to hypoxia and lactic acidosis. Myocardium, being particularly vulnerable to hypoxia, is one of the most damaged organs in course of CO intoxication. A CASE REPORT: We present a case report of severe CO poisoning in a 66-year old man, that led to significant repolarization abnormalities. Diffuse ST segment depression associated with significant QT interval prolongation up to QTcB 595ms was observed in the electrocardiogram at admission. Other potential causes of QT prolongation as hypothermia, dyselectrolitemia or QT prolonging drugs use were excluded. No regional neither global contractility dysfunction was observed on echocardiography. ECG recorded 6 hours after admission showed normalization of ST segment but only slight shortening of QTc to 550 ms.

Effects of intranasal kinetic oscillation stimulation on heart rate variability.

BACKGROUND: Kinetic oscillation stimulation in the nasal cavity (KOS) has been shown to have positive symptomatic effects in subjects with non-allergic rhinitis and in patients with migraine. METHODS: To evaluate the effect of KOS on autonomic function, we assessed heart rate variability (HRV) in this small exploratory study in 12 healthy subjects. KOS treatment was performed using a minimally invasive system with a single-use catheter inserted into the nasal cavity. During treatment, the tip was inflated and oscillated with a mean pressure of 95 millibar and amplitude of the oscillations of 100 millibar at a frequency of 68 Hz. Treatment was given for 15 minutes sequentially on each side. Heart rate variability was assessed during five 30-minutes periods before, during and immediately after KOS treatment and 3.5 hours thereafter. KOS resulted in a substantial reduction of HRV. RESULTS: As compared to baseline recorded during 30 minutes preceding treatment, VLF was reduced by 65%, LF by 55%, the ratio LF/HF by 44%, with somewhat smaller observed effects in the time domain; SDNN and RMSDD were reduced by of 36% and 18%, respectively. Heart rate remained stable during treatment with minimal mean changes from 68 ± 7 bpm before to 68 ± 9 and 69 ± 9 bpm during and after treatment. Reduction of HRV parameters was consistently seen in all subjects, with rapid onset and return towards baseline values during post-treatment observation periods. CONCLUSIONS: KOS has an effect on the autonomic balance with pronounced heart-rate independent reduction on HRV.

Self-terminating ventricular fibrillation recorded by an implantable loop recorder as a cause of syncope - A case report.

Ventricular fibrillation (VF) is the most common arrhythmia leading to sudden cardiac death, but in rare cases VF can manifest as a syncope, provided that it will self-terminate. We present a case of a 45-year old female with a history of unexplained syncopal episodes despite exhaustive diagnostics. Implantable loop recorder documented an episode of idiopathic, self-terminating VF as a cause of syncope.

The clinical value of T-wave alternans derived from Holter monitoring.

Microvolt-level T-wave alternans (TWA) assessed by spectral method during an exercise stress test has been widely studied for risk stratification. Several studies have documented the association of a positive TWA with total mortality and arrhythmic events. Nevertheless, the need to achieve an elevated and stabilized heart rate resulting in a considerable proportion of indeterminate test results constitutes one of the main limitations of this method. It is well recognized that arrhythmic events may be triggered not only by physical but also by mental stress and are not necessarily associated with exercise. Detection of TWA in ambulatory electrocardiogram recordings during daily activities might be a valuable option in risk stratification. This review describes the modified moving average (MMA) technique for detection of TWA and summarizes the results of clinical studies on the prognostic value of MMA-TWA. So far, MMA-TWA has been studied in over 5000 patients including those evaluated during exercise as well as during daily activities with ambulatory ECG recordings. The results of these studies indicate that increased MMA-TWA is associated with higher risk of cardiac mortality and arrhythmic events.

Risk score to assess mortality risk in patients undergoing transvenous lead extraction.

AIMS: The main aim of this study was to assess 1-year mortality and its predictors in a cohort of patients who underwent transvenous lead extraction (TLE) procedure. METHODS: Retrospective analysis of clinical characteristics and 1-year follow-up of patients referred for a TLE procedure in a single, high-volume center between June 2006 and October 2014 was performed. RESULTS: The studied population included 130 patients (82 males; mean age 64 ± 15 years) implanted with pacemakers (74%), implantable cardioverter defibrillators (15%), or cardiac resynchronization therapy defibrillator (11%). Indications for the extraction included infective endocarditis (40.5%), pocket infection (18.5%), and lead fault or failure (41%). Total radiological success rate was 90% while clinical success rate was 93.5%. The cumulative 1-year mortality was 28%. Mortality was higher in a group of older patients (94.4% vs 68%, P = 0.001) and those with chronic kidney disease (33.3% vs 4.3 %, P = 0.0002) as well as in patients after removal of high voltage lead (88.9% vs 26.3%, P = 0.01). Higher mortality was also related to infection as an indication for TLE (37.2% vs 13.5%, P = 0.002). Following these findings a new risk score model named IKAR (I = infective indications; K = kidney dysfunction; A = age ≥ 56; R = removal of high voltage lead) was constructed. Patients with IKAR score ≥3 points were characterized by 79% mortality as compared to 16% in those with a score 1-2 points. CONCLUSIONS: One-year mortality of patients undergoing TLE procedure can be predicted by using IKAR risk score.

2017 ISHNE-HRS expert consensus statement on ambulatory ECG and external cardiac monitoring/telemetry.

Ambulatory ECG (AECG) is very commonly employed in a variety of clinical contexts to detect cardiac arrhythmias and/or arrhythmia patterns which are not readily obtained from the standard ECG. Accurate and timely characterization of arrhythmias is crucial to direct therapies that can have an important impact on diagnosis, prognosis or patient symptom status. The rhythm information derived from the large variety of AECG recording systems can often lead to appropriate and patient-specific medical and interventional management. The details in this document provide background and framework from which to apply AECG techniques in clinical practice, as well as clinical research.

[Technical options of electrotherapy in patients with vasovagal syncope]. / Techniczne mozliwosci elektroterapii u osób z omdleniami wazowagalnymi.

Syncope is a symptom of the disease with diverse etiology and can be evidence of both benign and very serious life-threatening conditions. Vasovagal syncope(VVS), with prevalence about 35% of the general population, is most frequent causes of transient loss of consciousness (T-LOC). Most cases of vasovagal syncope requires conservative treatment. Although cardioinhibitory type of VVS characterized by a significant bradycardia or pause of the heart rate and can be treated with continuous electrotherapy. This article discuss cardiac pacing and technical solutions for the treatment of VVS. Available cardiac pacing methods used to detect and break VVS such as Rate Drop Response (RDR), Closed Loop Stimulation (CLS) and rate response driven by variations of myocardial contractility like Peak Endocardial Acceleration (PEA), has been presented.

[Long-term prognosis in patients with vasovagal syncope after pacemaker implantation]. / Rokowanie odlegle u pacjentów z omdleniami wazowagalnymi po implantacji kardiostymulatora.

Patients with syncope, without presence of a structural or primary electrical disease, have a very good prognosis. On the other hand, recurring syncope has a negative impact on quality of life and involves a real risk of physical injuries. Vasovagal syncope usually requires no medical therapy and the most commonly recommended instruction include avoidance of fainting triggers, exercise that mainly provoke leg muscles tension, increase salt consumption and drink indicated amount of fluids. In the case cardioinhibitory type of vasovagal syncope the pacemaker implantation can consider. Unfortunately, not all patients benefit from this treatment. Medical society clearly highlights that proper qualification of VVS patients is the most important factor for cardiostimulator implantation. This article aims to summarize the most important research and guidelines concerning cardiac pacing for patients with vasovagal syncope.

[Clinical procedure in amiodarone-induced thyroid dysfunction]. / Postepowanie kliniczne w poamiodaronowych zaburzeniach czynnosci gruczolu tarczowego.

Amiodarone is an antiarrhythmic drug frequently used in everyday clinical practice. Its mechanism of action involves the interaction with many receptors, including those in the cardiac conduction system. Amiodarone usefulness is protect in the treatment of a variety of tachyarrhythmias, both benign and life-threatening. In contrast to other antiarrhythmic drugs, amiodarone is characterized by high therapeutic efficacy, both in patients with normal and impaired left ventricular systolic function. A significant limitation of its is associated with side effects including thyroid gland dysfunction. Disturbances of this organ associated with amiodarone are an important diagnostic and therapeutic problem. They may contribute to the occurrence of both Amiodarone- Induced Thyrotoxicosis (AIT) and Amiodarone-Induced Hypothyroidism (AIH). The risk of such complications should be considered for each patient individually, taking into account thyroid function at the beginning of pharmacotherapy. Appropriate procedure, both before and after treatment allows a rapid diagnosis and treatment of thyroid disturbances. It seems that the best parameter used to assess the hormonal imbalance during amiodarone therapy is the concentration of the free triiodothyronine (fT3). The evaluation of thyroid function should be performed before starting pharmacotherapy, and then repeated every six months. In the case of a thyroid dysfunction, assessment must be performed immediately according to standard diagnostic and therapeutic regimens. Despite abnormal thyroid function, high efficiency of amiodarone and relatively small risk of thyroid damage allows continuation therapy. Amiodarone therapy requires a care from both cardiologist and endocrinologist. The aim of this paper is to present the state of art of evaluation of the thyroid function and procedures implemented in care of thyroid dysfunction before and during treatment with amiodarone.

[Atrial fibrillation in patients with heart failure].

The most common arrhythmia is atrial fibrillation, which is very often associated with heart failure. Treatment of both clinical entries are difficult and became a clinical, social and economic challenge in last decades. The authors present clinical aspects connected with a coexistence of HF and AF. They discuss systematic review of research studies regarding medical therapy and invasive electrotherapy.

Automatic SVM classification of sudden cardiac death and pump failure death from autonomic and repolarization ECG markers.

BACKGROUND: Considering the rates of sudden cardiac death (SCD) and pump failure death (PFD) in chronic heart failure (CHF) patients and the cost-effectiveness of their preventing treatments, identification of CHF patients at risk is an important challenge. In this work, we studied the prognostic performance of the combination of an index potentially related to dispersion of repolarization restitution (Δα), an index quantifying T-wave alternans (IAA) and the slope of heart rate turbulence (TS) for classification of SCD and PFD. METHODS: Holter ECG recordings of 597 CHF patients with sinus rhythm enrolled in the MUSIC study were analyzed and Δα, IAA and TS were obtained. A strategy was implemented using support vector machines (SVM) to classify patients in three groups: SCD victims, PFD victims and other patients (the latter including survivors and victims of non-cardiac causes). Cross-validation was used to evaluate the performance of the implemented classifier. RESULTS: Δα and IAA, dichotomized at 0.035 (dimensionless) and 3.73 µV, respectively, were the ECG markers most strongly associated with SCD, while TS, dichotomized at 2.5 ms/RR, was the index most strongly related to PFD. When separating SCD victims from the rest of patients, the individual marker with best performance was Δα≥0.035, which, for a fixed specificity (Sp) of 90%, showed a sensitivity (Se) value of 10%, while the combination of Δα and IAA increased Se to 18%. For separation of PFD victims from the rest of patients, the best individual marker was TS ≤ 2.5 ms/RR, which, for Sp=90%, showed a Se of 26%, this value being lower than Se=34%, produced by the combination of Δα and TS. Furthermore, when performing SVM classification into the three reported groups, the optimal combination of risk markers led to a maximum Sp of 79% (Se=18%) for SCD and Sp of 81% (Se=14%) for PFD. CONCLUSIONS: The results shown in this work suggest that it is possible to efficiently discriminate SCD and PFD in a population of CHF patients using ECG-derived risk markers like Δα, TS and IAA.