QRS Complex Duration Research Articles

LBBAP versus conventional CRT reimplantation after transvenous lead extraction: report from a monocentric experience

Abstract Background Cardiac resynchronization therapy – defibrillator (CRT-D) reimplantation after transvenous lead extraction (TLE) can be challenging due to fibrotic remnants and absence of target veins. Left bundle branch area pacing (LBBAP) is emerging as an alternative to conventional CRT, but data is lacking about its feasibility after TLE. Purpose To explore the feasibility and safety of LBBAP as alternative to conventional CRT though epicardial pacing (EP) in patients undergoing CRT-D TLE. Methods We prospectively enrolled all patients admitted for complete CRT-D extraction and replacement from July 2022 to September 2023. At the moment of reimplantation, the choice between EP and LBBAP was made on the basis of posterolateral CS branches viability at post-extraction CS venography. Procedural success was defined as effective stimulation and absence of major complications while the primary endpoints were procedural time, QRS complex duration and electrical lead parameters. Patients undergoing LBBAP and EP reimplantation were compared. Results Twenty-six patients were enrolled (mean age 68.3 ± 7.2 years, p = 0.538; 12% females, p = 0.859). The most frequent cause of device extraction was pocket infection (58%, p = 0.773). Seventeen (65%, p = 0.783) patients had estimated high risk of procedural severe complications measured by EROS score. Overall, 80 leads were extracted. Mechanical extractors and snares were deemed necessary in 35 cases (43%, p = 0.917) and in 2 cases, respectively. Almost all patients (n=25, 96%) underwent right-sided reimplantation. Procedural success was achieved in 24 cases (92%). Compared to standard CRT through EP, LBBAP reimplantation accounted for a faster procedure (109.5 ± 34.2 vs. 126.5 ± 46.8 min; p = <0.001), less radiologic exposure (877.0 ± 234.6 vs. 1332.0 ± 515.1 sec, p <0.001) and better ventricular pacing thresholds (0.7± 0.1 vs. 1.8± 0.6 V, p <0.001). Despite a similar pre-extraction paced QRS duration (127.4 ± 13.8 vs. 133.0 ± 14.4 msec; p = 0.610), LBBAP reported significant improvement in final QRS duration (105.0 ± 13.1 vs. 127.1 ± 10.4 msec, p < 0.001) with major reduction in QRS duration (- 10.9 ± 7.5 vs - 6.8 ± 10.1, p < 0.001). Conclusion After a CRT TLE procedure, LBBAP reimplantation accounted for lower procedure duration, lower radiologic exposure, narrower QRS and lower ventricular pacing thresholds, demonstrating to be a valuable alternative to EP.

Influence of Bust Size and Waist Circumference on Electrocardiographic Left Ventricular Voltage Index in Blacks Africans

Background: Several studies have investigated on relationship between anthropometric characteristics andelectrocardiographic left ventricular mass (LVM). These studies, performed mainly in Caucasians, have mostlyfocused on influence of body mass index on left ventricular voltage indices (LVVI), and rarely on bust size and/or waist circumference.Aim: To determine influence of bust size and waist circumference on LVVI in healthy sedentary people of blackAfrican origin.Method: Experimental, prospective, cross-sectional descriptive study including 66 volunteers (20 women) aged 18to 35 years. They were received in morning on empty stomach. Bust size and waist circumference were measuredwith tape measure. Standard electrocardiogram was performed at rest. R and S wave amplitude and QRScomplex duration were measured. Sokolow-Lyon, R in aVL, Cornell and Cornell product indexes were calculated.Correlation was sought between each LVVI and anthropometric characteristics studied.Results: Bust size and waist circumference were positively correlated with LVVI. Correlation with bust size wasstatistically significant for all LVVI except for R in aVL index, while for waist circumference it was only significantwith R in aVL index.Conclusion: This study confirms relationship between anthropometric characteristics and LVVI. Therefore,interpretation of LVM anomalies from LVVI should also take into consideration morphotype of each individual.

Association of QRS Duration with Echocardiographic Left Ventricular Dimensions

Background: QRS duration (QRSd) is used to diagnose left bundle branch block (LBBB) and is important for determining cardiac resynchronization therapy eligibility. Others have reported associations of left bundle branch block (LBBB) and interventricular conduction delay with left ventricular (LV) systolic and diastolic dysfunction in patients without clinical HF. Individualized QRSd thresholds may improve diagnosis and intervention strategies. The goal of this study was to assess the relations of QRS duration to echocardiographic left ventricular (LV) dimensions in individuals. Methods: This was a hospital-based cross-sectional analytical study. A total of 134 purposively selected respondents were included in the study from the patients attending the outpatient or inpatient department of cardiology, Dhaka Medical College Hospital, advised for an echocardiogram. They were divided into two groups depending on their QRS complex duration (Group I≤100 ms and Group II>100 ms). After taking informed written consent, a case record form was filled and Echo measurements were taken following standard procedure with confidentiality. Results: Among the respondents, the mean age was found 52.68 ± 14.24 years. The majority were male (68%), and around 1/3rd of the respondents were overweight or obese. Males were found to have less QRS duration than females (p<0.001) but there was no difference in age (p=0.814) between the groups. All the risk factors considering obesity, diabetes mellitus, hypertension, family history, smoking status, and dyslipidemia were found in similar proportions in both groups (p>0.05). The study found that the interventricular septum thickness and inferolateral wall thickness were higher among those having a QRS duration of more than 100 ms (Group II), but this difference was not significant (p > 0.05). On the other hand, left ventricular diastolic dimension, systolic dimension, and left ventricular mass were found to be increased significantly (p<0.05) with a reduction in ejection fraction in Group II (p<0.05). Conclusion: Left ventricular diastolic and systolic dimensions along with left ventricular mass significantly increase according to QRS duration among the patients. Meanwhile, a reduction in ejection fraction was also evident. (Bangladesh Heart Journal 2024; 39(2): 144-150

Morphographic Changes in the Electrocardiogram of Colossoma macropomum Caused by Exposure to Manganese.

Manganese (Mn2+) is an abundant chemical element in the earth's crust and is present in soil, water, and industrial environments, including mining, welding, and battery manufacturing. Manganese (Mn) is an essential metal needed as a cofactor for many enzymes to maintain proper biological functions. Excessive exposure to Mn in high doses can result in a condition known as manganism, which results in disorders of the neurological, cardiac, and pulmonary systems. The aim of this study was to assess cardiac susceptibility to manganese intoxication in Colossoma macropomum subjected to a fixed concentration of 4 mg/mL for a period of up to 96 h. This study used 45 Tambaquis (30.38 ± 3.5 g) divided into five groups of 9 animals/treatment. The treated groups were exposed to the manganese concentration for a period of 24, 48, 72, and 96 h, after which the animals' ECGs were recorded, showing heart rate, R-R interval, P-Q interval, QRS complex duration and S-T interval. The results showed that cardiac activity decreased as the contact time increased, with an increase in the P-Q and S-T intervals. This indicates that the breakdown of circulatory homeostasis in these animals was caused by contact time with manganese.

Diagnosis of Narrow QRS Tachycardia

Narrow QRS tachycardia is a common clinical condition characterized by a heart rate exceeding 100 beats per minute and a QRS complex duration of less than 120 ms. This article provides an overview of the diagnostic approach to narrow QRS tachycardia, focusing on the differentiation between various supraventricular tachycardias, such as atrioventricular nodal reentrant tachycardia (AVNRT), atrioventricular reentrant tachycardia (AVRT), atrial tachycardia (AT), and sinus tachycardia. The discussion includes an analysis of the presenting symptoms, electrocardiographic (ECG) findings, and the use of vagal maneuvers and pharmacological agents in diagnosis.

A Comparative Analysis of Apical Rocking and Septal Flash: Two Views of the Same Systole?

Heart failure (HF) is a complex medical condition characterized by both electrical and mechanical dyssynchrony. Both dyssynchrony mechanisms are intricately linked together, but the current guidelines for cardiac resynchronization therapy (CRT) rely only on the electrical dyssynchrony criteria, such as the QRS complex duration. This possible inconsistency may result in undertreating eligible individuals who could benefit from CRT due to their mechanical dyssynchrony, even if they fail to fulfill the electrical criteria. The main objective of this literature review is to provide a comprehensive analysis of the practical value of echocardiography for the assessment of left ventricular (LV) dyssynchrony using parameters such as septal flash and apical rocking, which have proven their relevance in patient selection for CRT. The secondary objectives aim to offer an overview of the relationship between septal flash and apical rocking, to emphasize the primary drawbacks and benefits of using echocardiography for evaluation of septal flash and apical rocking, and to offer insights into potential clinical applications and future research directions in this area. Conclusion: there is an opportunity to render resynchronization therapy more effective for every individual; septal flash and apical rocking could be a very useful and straightforward echocardiography resource.

Electrocardiographic predictors of haemodynamic benefit from biventricular pacing: the role of atrioventricular timing measures

Abstract Background Patients with heart failure (HF) and left bundle branch block (LBBB) are selected for biventricular pacing (BVP) cardiac resynchronisation therapy (CRT) based on their 12-lead ECG QRS complex duration (QRSd). This is due to the long-held belief that BVP delivers its beneficial effects almost exclusively by reducing ventricular dyssynchrony. Recent work (1) suggests that atrioventricular delay (AVD) shortening is another key mechanism of benefit and, therefore, that atrioventricular timing may be an important CRT substrate. The ideal 12-lead ECG measure to facilitate patient selection that yields benefits from this mechanism is yet to be elucidated. Purpose We set out to establish whether incorporating a measure of AV delay provides additional benefit over and above using QRSd when using the 12-lead ECG to select patients who are likely to obtain haemodynamic benefit from BVP. Methods We identified patients in sinus rhythm with HF and LBBB meeting clinical criteria for CRT who had undergone implantation of a BVP device and had also undergone high-precision haemodynamic assessment of BVP. This is where pacing is alternated between atrium-only pacing (AAI) and DDD pacing using BVP multiple times for each of a full range of AVDs during continuous beat-by-beat blood pressure recording to determine the peak haemodynamic benefit of BVP in each patient. We extracted potentially predictive, pre-specified intrinsic (unpaced) ECG features that incorporated left or right AV timing to varying extents: PR interval (PR), end-of-p-wave-to-R-wave-peak-time-V6 (Pend-RWPTV6), start-of-p-wave-to-end-of-QRS (P-QRSend) as well as conventional QRSd. Pearson's test assessed the unadjusted correlation between intrinsic ECG intervals and BVP haemodynamic benefit(∆SBP). A multiparametric regression analysis model was constructed to account for confounders and interactions between different ECG features. Results 53 eligible patients were identified. 39 were male (73.6%), 31 had non-ischaemic aetiology (58.5%), mean LVEF was 27.6% ± SD 4.79 and mean LVEDD was 57.9± SD 9.4mm. Unadjusted correlations between intrinsic ECG features were not strong but favoured P-QRSend as a potentially predictive feature; R2 values: PR 0.28 (p=0.04), Pend-RWPTV6 0.19 (p=0.18), P-QRSend 0.27 (p=0.054), QRSd 0.045 (p=0.75). However, the multiparametric model revealed that utilising both PR interval and Pend-RWPTV6 in a predictive model showed better-adjusted correlation with BVP haemodynamic benefit (R2 0.54, p=0.04). Conclusion ECG features that incorporate either right (PR interval) or left (Pend-RWPTV6) AVD or both (P-QRSend) are superior to QRSd for predicting haemodynamic benefit from BVP in patients with HF and LBBB. This further reinforces the role of AVD shortening as a mechanism of benefit of BVP and suggests that selecting patients on the basis of AV timing may yield more overall benefit from CRT delivered by BVP or potentially conduction system pacing.ECG interval measurementCorrelation Graphs

Incidence and Predictors of Ventricular Arrhythmia after Cardiac Resynchronization Therapy Device Implantation

Background: Cardiac resynchronization therapy (CRT) serves as a pivotal therapeutic modality for patients with heart failure with reduced ejection fraction and biventricular dyssynchrony. The implementation of CRT not only mitigates the risk of sudden cardiac death but also enhances the overall quality of life. Knowledge concerning the incidence and predictive factors of ventricular arrhythmia (VA) following CRT implantation is invaluable for optimizing future CRT protocols and assessing cost-effectiveness. Materials and Methods: The present research constituted a retrospective cohort analysis with a nested case-control study, conducted between January 2005 and April 2018. Inclusion criteria encompassed patients who experienced heart failure with a left ventricular ejection fraction (LVEF) of less than 35%, displayed a QRS complex duration exceeding 120 milliseconds on electrocardiography, which underwent optimized pharmacological treatment, and subjected to a minimum one-year follow-up post-implantation. Results: One hundred forty-six CRT patients were included, and 47.9% (95% confidence interval [CI] 39.9 to 55.9) VA was detected. The average age at the time of implantation was 64 years. Only male, at 68.5%, was the baseline factor to increase the risk of VA (odds ratio [OR] 2.20, 95% CI 1.07 to 4.53, p=0.031). The other significant predictors for VA included fewer improvements in QRS width or LVEF post-implantation (p<0.001 and 0.001, respectively). Conversely, a reduction of at least 7 milliseconds in QRS width following implantation correlated with a significant decline in VA events (p<0.001), exhibiting a sensitivity of 80.3% and a specificity of 65.7%. Conclusion: In patients who underwent CRT implantation, the risk factors determining the occurrence of VAs included male gender and minimal post-procedural improvements in QRS width or LVEF. On the contrary, a narrowing of the QRS width by more than 7 milliseconds post-implantation was significantly associated with a reduced incidence of ventricular arrhythmic events.

Evaluation of a digital stethoscope for electrocardiographic recording in donkeys: Preliminary results

The digital stethoscope (DS) is a cost-effective single-lead digital stethoscope that allows simultaneous electrocardiographic (ECG) and phonocardiographic recordings on a smartphone. Despite its application in small animals and horses, there are currently no studies on its use in donkeys. The aim of this study was to evaluate the use of a new smartphone-based DS device in recording ECG tracings in donkeys. Standard base-apex lead ECG (sECG) and single-lead DS ECG (dECG) were simultaneously recorded for at least 30 s. Both sECG and dECG tracings were analysed by the same operator, recording heart rate, ECG waves and intervals, and the presence and duration of artefacts. Thirty-seven donkeys were included. The dECG tracings were interpretable in all the animals (100 %). The results showed perfect agreement between the sECG and dECG data for the classification of heart rhythm and P-wave polarity. Strong agreement was found in the evaluation of heart rate calculated manually and automatically by the smartphone app, QRS complex polarity, T wave polarity, and duration of the PR interval. However, no agreement was found in the evaluation of P wave duration, QRS complex duration and amplitude, and T wave duration and amplitude. In conclusion, although this is only a preliminary study, the DS was a valid, practical, and easy to use electrocardiographic tool for recording good-quality ECG tracings to assess the ECGs of donkeys in the field.

Real-time three-dimensional transthoracic echocardiography in quantification of left ventricular dyssynchrony

Aim. To compare endocardial and epicardial left ventricular (LV) pacing using real-time electrocardiography (ECG)-synchronized three-dimensional echocardiography (3DE).Methods. Experimental intraoperative study included 88 points obtained from 12 patients with compensated heart failure of II-IV functional class NYHA (LV ejection fraction < 35%) and cardiac resynchronization therapy indications - ECG pattern of complete left bundle branch block (LBBB) and QRS complex duration > 150 ms. During isolated LV pacing as part of cardiac resynchronization therapy implantation procedure endocardial and epicardial stimulation points matched under fluoroscopic control using quadripolar coronary sinus leads and endocardial electrodes for temporary pacing were obtained. The overall number of corresponding pacing sites included 44 endocardial and 44 epicardial stimulation positions. The mean age of patients was 68.5 [63; 73.5] years, 83% males (n=10). Before study enrollment, 12-channel ECG, echocardiography, and a six-minute walk test were performed for all participants along with cardiac magnetic resonance imaging and control coronary angiography if indicated. The prevalence of coronary heart disease was 50% (n=6) while dilated cardiomyopathy was the most common etiology of chronic heart failure in other cases. Intraoperative ECG with estimation of paced QRS complex morphology at each point was registered via LabSystem Pro Electrophysiological Recording System (Bard Electrophysiology, USA). 3DE was performed using TomTec and Philips Qlab 3DQ Advanced software (Philips Medical Systems, USA).Results. Three-dimensional parametric imaging of LV regional segmental excursion and myocardial contractility using 3DE revealed statistically significant difference in semi-quantative parameters such as ExcAvg (p<0.001), ExcMax (p=0.001), ExcMin (p<0.001) and LV ejection fraction based on 3D modelling (p=0.003) while endocardial pacing was more beneficial. During the course of endocardial stimulation, the 3DE dyssynchrony index estimated at the 2nd stimulation site was also significantly lower (p=0.03). Identical dyssynchrony parameters valid for the 16 and 12-segment 3D models (SDI-16, Tmsv-12SD) (at p=0.06) demonstrated only a tendency for significant difference. The duration of QRS complex at the time of endocardial pacing was significantly shorter (<190 [179;215] ms) (p=0.0008). Semi-quantitative and quantitative 3DE parameters showed the benefit of endocardial pacing resulting in cardiac contractility improvement with less dyssynchrony and LV volume reducing during intraoperative period.Conclusion. Endocardial pacing has potential benefit over the epicardial pacing represented by intraoperative dynamics of LV global and local contractility, intraventricular dyssynchrony estimated by 3DE and also ECG criteria. 3DE is helpful in more precise and reproducibile determing of late activation zone for target LV lead placement that is more manoeuvrable in case of endocardial stimulation.

A comparison of electrocardiographic parameters in e-cigarette users, conventional cigarette smokers, and non-smokers

BackgroundSmoking is a major preventable risk factor for cardiovascular morbidity and mortality. Tobacco smoking induces atherosclerosis, ischemic heart diseases, and arrhythmias. The impact of electronic cigarettes on cardiovascular health is still controversial. This study aimed to evaluate the electrocardiographic parameters in chronic electronic cigarette users compared to chronic conventional cigarette smokers and a non-smoker control group of matched age and gender.ResultsThe study involved 105 volunteers with no history of chronic or cardiovascular diseases or cardioactive drug use. Participants were assigned into three study groups, chronic e-cigarette users, conventional cigarette smokers, and non-smokers, each consisting of 35 participants. Demographic data, smoking history, vital signs, and 12-lead electrocardiogram (ECG) were evaluated. Demographic data were insignificantly different among all study groups. The mean heart rate was significantly higher in chronic electronic cigarette users and conventional cigarette smokers compared to non-smokers (p < 0.001).QRS complex duration was significantly shorter in e-cigarette users and conventional smokers compared to non-smokers (p < 0.001). Prolonged QT and QTc intervals duration were recorded in e-cigarette users and conventional smokers compared to non-smokers (p < 0.001). All the ventricular repolarization indices (T wave—peak to T-end (Tpe) interval, TPe/QT ratio, and TPe/QTc ratio were significantly prolonged in chronic e-cigarette users, and conventional smokers compared to non-smokers (p < 0.001). Mean systolic, diastolic blood pressure, P wave amplitude and duration, and PR interval were insignificantly different between all groups (P > 0.05).ConclusionsChronic e-cigarette use is associated with higher heart rates, shorter QRS complex, prolonged QT, QTc duration, and prolonged ventricular repolarization indices compared to non-smokers of matched age and gender. Conclusively, e-cigarette use is associated with negative cardiovascular effects like conventional cigarette smoking.

Cryoanesthesia in tambaqui Colossoma macropomum: Behavioral and electrocardiographic responses

Cryoanesthesia is a low-cost procedure that has advantages for use in fish, however, there are only a few studies dealing with the electrophysiological evaluation and its safety-related aspects. The relationship between behavior and electrocardiographic activity allows for the monitoring of functional changes in cardiac activity in fish submitted to low temperatures. This study aimed to describe the behavior and cardiac effects of cryoanesthesia in juvenile tambaqui (Colossoma macropomum) through electrocardiographic assessment. For this purpose, 27 juveniles of tambaqui (28.9 ± 4.2 g) were used and essayed into two experiments. Experiment 1: behavioral evaluation (n = 9) and Experiment 2: electrocardiographic recordings with control group (n = 9), and fish submitted to water at 5 °C in baths followed by subsequent recovery at a temperature of 26 ± 2 °C (n = 9). Each cardiac activity recording lasted 1200 s, after which fish were immediately transferred to a bath in water at 26 ± 2 °C, for 600 s. Heart rate, QRS amplitude, QRS complex duration and RR, PQ and QT intervals were analyzed. The results showed that four tracing patterns emerged which characterized the induction phases of cryoanesthesia throughout exposure to water at 5 °C. In phase 1, there was a decrease in the amplitude of the QRS complex. In phase 2, there was an increase in the amplitude of the QRS complex and maintenance of sinus rhythm. Phase 3 showed a gradual loss of cardiac function with the onset of an atrioventricular blockade. In phase 4, a cardiac arrest occurred, albeit reversible. Heart rate decreased as exposure time was longer at low temperatures. The fish recovered completely from cryoanesthesia after the increase in temperature, showing normal heartbeats, and QRS complex duration, QT, RR, and HR intervals being restored with maintenance of sinus rhythm, indicating recovery of fish hemodynamics. Overall, tambaqui juveniles at 5 °C showed a time-dependent and gradual reduction of motor activity with loss of postural reflex and immobility. Cardiac response was a function of temperature and progressed to a reversible cardiac arrest. During recovery, stages similar to those of induction were observed, but in the opposite direction, until recovery of the postural reflex. Cryoanesthesia can be used as an alternative method for the immobilization of C. macropomum.

The role of QRS complex prolongation in predicting severe toxicity in single-xenobiotic overdose

Objective The QRS complex duration is commonly used to prognosticate severity, predict outcomes, and indicate treatment in overdose. However, literature to support this practice is mixed in tricyclic antidepressant overdoses and absent in non-tricyclic antidepressant overdoses. Our objective was to assess the validity of QRS complex duration as a prognostic marker in overdose. Methods This was a secondary analysis of cases reported to the Toxicology Investigators Consortium between January 1, 2010, and December 31, 2022. Cases were assessed to determine the six xenobiotics most associated with QRS complex prolongation. All cases involving these six xenobiotics, regardless of QRS complex duration, constituted the study cohort. Inclusion criteria were cases of patients older than 12 years old with single-xenobiotic exposures. Clinical outcomes evaluated were seizure, ventricular dysrhythmia, metabolic acidosis, and death. Results Of 94,939 total cases, diphenhydramine, amitriptyline, bupropion, quetiapine, nortriptyline, and cocaine were most associated with QRS complex prolongation. Inclusion criteria were met by 4,655 cases of exposure to these xenobiotics. QRS complex prolongation was associated with increased odds ratio of seizure in all included xenobiotics, of ventricular dysrhythmia in all included xenobiotics except nortriptyline, and of metabolic acidosis or death in all included xenobiotics except nortriptyline and quetiapine. A normal QRS complex duration had a negative predictive value of greater than or equal to 93.0 percent of developing metabolic acidosis and 98.0 percent of developing a ventricular dysrhythmia or death from the xenobiotics studied. Discussion This study demonstrates that patients with QRS complex prolongation from all six xenobiotics studied had an increased prevalence and odds of developing severe outcomes. Furthermore, patients who did not develop QRS complex prolongation were unlikely to develop a ventricular dysrhythmia, metabolic acidosis, or death. These findings were noted in six xenobiotics that mechanistically can cause QRS complex prolongation through sodium channel or gap junction inhibition. Conclusion Identification of patients at risk for severe outcomes after overdose can be aided by measuring the QRS complex duration. If prospectively validated, these outcomes have implications on risk stratification, disposition level of care, and appropriateness of treatments.

Qualitative and Quantitative Electrocardiogram Parameters in a Large Cohort of Children with Duchenne Muscle Dystrophy in Comparison with Age-Matched Healthy Subjects: A Study from South India.

Electrocardiography (ECG) remains an excellent screening tool for cardiac assessment in Duchenne muscular dystrophy (DMD), but an accurate interpretation requires comparison with age-matched healthy controls. We examined various ECG parameters in children with DMD, in comparison with age-matched controls. Standard 12-lead ECG tracings of serial patients were screened for quality and selected. Controls were healthy, age-matched school-going children. Both quantitative and qualitative ECG parameters were analyzed. After screening, ECGs from 252 patients with DMD (8.32 ± 3.12 years, 2-21 years) and ECGs from 151 age-matched healthy controls (9.72 ± 2.23, 4-19 years) were included. A significantly higher heart rate, shorter R-R interval, and taller R wave in V1 were seen across all age group of DMD in comparison to controls, with the difference increasing with age. While QT prolongation was seen in all age groups of DMD, QTc prolongation was seen only at 10 years or more. Incomplete right bundle branch block (RBBB) and pathological Q waves in inferolateral leads were exclusive in DMD, with the latter declining with age. Evidence for left ventricular (LV) pathology, such as tall R in V5/V6, increase in SV1 + RV6 height, and QRS complex duration, were seen only in the age group of 10 years or more. Stratification based on age and comparison with age-matched healthy subjects showed that several ECG parameters were influenced by age, and it also identified age-dependent evidence for LV pathology and QTc prolongation in DMD.

Electrocardiographic, biochemical, and scintigraphic evidence for the cardioprotective effect of paricalcitol and vitamin D3 on doxorubicin-induced acute cardiotoxicity in rats.

We aimed to investigate the possible cardioprotective effects of paricalcitol (PR), its vitamin Dreceptor agonist, and vitamin D3 (VIT-D3) on an experimental model of doxorubicin (DX) cardiotoxicity by 99mTc-PYP scintigraphy, electrocardiographic (ECG) and biochemical methods. Forty-two male Wistar/Albino rats (250‒300 g; aged 10‒12 weeks) were randomly separated into six groups, namely into control (CN), doxorubicin (DX), paricalcitol (PR), vitamin D3 (VIT-D3), paricalcitol + doxorubicin (PR+DX), and vitamin D3 + doxorubicin (VIT-D3+DX) groups. Cardiotoxicity was induced by three doses of DX (18 mg/kg, i.p.) at 24-hour intervals on days 18, 19 and 20. PR (0.5 ug/ kg, i.p) and VIT-D3 (5,000IU/kg, i.p) were injected for 20 days before and after the application of DX (18 mg/kg, i.p.). On day 21 of the experiment, biochemical parameters [tumor necrosis factor TNF-alpha (TNF-α); interleukin-6 (IL-6), nitric oxide (NO), and cardiac troponin T(cTnT)], as well as ECG and scintigraphic (99mTc-PYP) features were assessed. Compared to CN, DX significantly raised TNF-α, IL-6, and NO in heart tissue, cTnT in serum, 99mTc-PYP uptake in the myocardium, and ECG parameters, specifically QRS complex duration, QT interval duration, and ST-segment amplitude, while also reducing heart rate (p<0.001). Pretreatment with PR and VIT-D3 mitigated these abnormalities produced by DX in the heart (p<0.001). Results show that vitamin Dreceptor agonist paricalcitol and vitamin Dprotect against DX-induced cardiotoxicity through anti-inflammatory and antioxidant effects (Fig. 4, Ref. 59). Text in PDF www.elis.sk Keywords: paricalcitol, doxorubicin, vitamin D, ECG, 99mTc-PYP scintigraphy, cardiotoxicity, inflammation.

Outcomes in patients with hypertrophic cardiomyopathy developing left ventricular systolic dysfunction after septal reduction therapy

Abstract Background In hypertrophic cardiomyopathy (HCM), systolic dysfunction (SD), defined by a left ventricular ejection fraction (LVEF) &amp;lt;50% is associated with a poor prognosis. After septal reduction therapy (SRT), anticipated alterations in left ventricular geometry and septal desynchrony may lead to reduction in LVEF. The prognostic significance of a reduction in LVEF &amp;lt;50% following SRT has not been established. Purpose To investigate the relationship between new development of SD post SRT and outcomes in HCM patients. Methods Of the 4110 HCM patients at our referral centre, 179 patients (4.4%) developed SD during follow up. The composite cardiac outcome was defined as the occurrence of new resuscitated cardiac arrest, ventricular tachycardia or ventricular fibrillation, and cardiac death after the onset of SD. Results Of the 179 patients who developed systolic dysfunction (SD), 67 patients developed it after undergoing septal reduction therapy (SRT) (4 patients underwent alcohol septal ablation, and 63 patients underwent septal myectomy). Both groups had similar characteristics with respect to age at the time of SD identification (59.9 ± 13.5 years vs. 59.6 ± 14.2 years, P=0.88), gender (76% men vs. 66% men, P=0.18), and genotype (24% had pathogenic or likely pathogenic variants vs. 28%, P=0.07). Despite similar LVEF at the time of presentation with SD between the two groups (44.1 ± 4.2% vs. 44.4% ± 4.9%, P=0.75), patients who underwent SRT had a lower maximal wall thickness (17.4 ± 4.9mm vs. 19.2 ± 5.2mm, P=0.02), larger end-diastolic diameter (5.3 ± 0.8mm vs. 4.8 ± 0.8mm, P&amp;lt;0.001) and end-systolic diameters (3.8 ± 0.7mm vs. 3.2 ± 0.8mm, P&amp;lt;0.001) than patients without SRT. Furthermore, patients who underwent SRT had a longer QRS complex duration (162.3 ± 20.6ms vs. 125.1 ± 31ms, p&amp;lt;0.001) and lower brain natriuretic peptide (BNP) (359.3 ± 632.9pg/ml vs. 690.8 ± 841.8pg/ml, p=0.04) during follow up than patients without prior SRT. During a mean follow up of 4.7 ± 4.1 years, the incidence of the composite cardiac outcome was significantly lower in patients who underwent SRT than in patients without prior SRT (7.5% vs. 20.5%, P=0.02). Notably, there were no observed sudden cardiac deaths observed in those who developed SD post SRT. Conclusion The prognosis for patients with HCM who underwent SRT and subsequently developed SD was significantly more favourable than for those who did not have a history of SRT. Thus, changes in left ventricular geometry and LVEF after SRT may not necessarily translate into a worsened prognosis.

Atrial and ventricular arrhythmia predictors with electrocardiographic parameters in myocardial infarction with non-obstructive coronary artery disease (MINOCA).

The clinical importance and recognition of myocardial infarction with non-obstructive coronary artery disease (MINOCA) is increasing. Nevertheless, no studies are investigating the risk of atrial fibrillation and ventricular arrhythmia in MINOCA patients. This study aimed to determine the risk of arrhythmia with electrocardiographic predictors in MINOCA patients. In this study, patients diagnosed with MINOCA and stable out-patients without significant lesions in their coronary arteries were compared. Morphology-voltage-Pwave duration electrocardiography (MPV ECG) score was used to determine atrial arrhythmia risk. QT interval and QT dispersion Tpeak-Tend time and Tpeak-Tend/QT interval were used to determine ventricular arrhythmia risk. A total of 155 patients were included in our study. Seventy-seven of these patients were in the MINOCA group. There was no statistically significant difference between the two groups in MPV ECG score (1.95 ± 1.03 vs 1.68 ± 1.14, p = 0.128). P-wave voltage, P-wave morphology and P-wave duration, which are components of the MPV ECG score, were not statistically significantly different. The QRS complex duration (90.21 ± 14.87 vs 82.99 ± 21.59 ms, p = 0.017), ST interval (271.95 ± 45.91 vs 302.31 ± 38.40 ms, p < 0.001), corrected QT interval (438.17 ± 43.80 vs 421.41 ± 28.39, p = 0.005) and QT dispersion (60.75 ± 22.77 vs 34.19 ± 12.95, p < 0.001) were statistically significantly higher in the MINOCA group. The Tpeak-Tend (89.53 ± 32.16 vs 65.22 ± 18.11, p < 0.001), Tpeak-Tend/QT interval (0.2306 ± 0.0813 vs 0.1676 ± 0.0470, p < 0.001) and Tpeak-Tend/corrected QT interval (0.2043 ± 0.6997 vs 0.1551 ± 0.4310, p < 0.001) ratios were also significantly higher in patients with MINOCA. In the MINOCA patients, there was no increase in the risk of atrial fibrillation based on ECG predictors. However, it was shown that there could be a significant increase in the risk of ventricular arrhythmia. We believe this study could be helpful for specific recommendations concerning duration of hospitalisation and follow up in MINOCA patients.

Triggers of Ventricular Fibrillation in Patients With Inferolateral J-Wave Syndrome

BackgroundThere are few data on ventricular fibrillation (VF) initiation in patients with inferolateral J waves. ObjectivesThis multicenter study investigated the characteristics of triggers initiating spontaneous VF in inferolateral J-wave syndrome. MethodsA total of 31 patients (age 37 ± 14 years, 24 male) with spontaneous VF episodes associated with inferolateral J waves were evaluated to determine the origin and characteristics of triggers. The J-wave pattern was recorded in inferior leads in 11 patients, lateral leads in 3, and inferolateral leads in 17. ResultsThe VF triggers (n = 37) exhibited varying QRS durations (176 ± 21 milliseconds, range 119-219 milliseconds) and coupling intervals (339 ± 46 milliseconds, range 250-508 milliseconds) with a right (70%) or left (30%) bundle branch block (BBB) pattern. Trigger patterns were associated with J-wave location: left BBB triggers with inferior J waves and right BBB triggers with lateral J waves. Electrophysiologic study was performed for 22 VF triggers in 19 patients. They originated from the left or right Purkinje system in 6 and from the ventricular myocardium in 10 and were undetermined in 6. Purkinje vs myocardial triggers showed distinct electrocardiographic characteristics in coupling interval and QRS-complex duration and morphology. Abnormal epicardial substrate associated with fragmented electrograms was identified in 9 patients, with triggers originating from the same region in 7 patients. Catheter ablation resulted in VF suppression in 15 patients (79%). ConclusionsVF initiation in inferolateral J-wave syndrome is associated with significant individual heterogeneity in trigger characteristics. Myocardial triggers have electrocardiographic features distinct from Purkinje triggers, and their origin often colocalizes with an abnormal epicardial substrate.

Clinical and prognostic significance of left ventricular dysfunction predictors in patients with ventricular ectopy and without structural heart disease

Aim. To determine the predictors of left ventricular dysfunction in patients with ventricular ectopic beats without structural heart disease.Material and Methods. We modeled ventricular ectopy in rats through early afterdepolarization (aconitine-induced arrhythmia) and delayed afterdepolarization (adrenaline arrhythmia). In addition, we modeled ventricular ectopy in rabbits and cats by delayed afterdepolarization (barium chloride-induced and strophanthin arrhythmias, respectively) and also modeled ventricular ectopy in dogs by re-entry hydrogen peroxide-induced arrhythmia. In addition to conventional electrocardiography parameters, we analyzed pre-ectopic interval, its variability, and the internal deviation index. Further, the study included 514 patients aged 16 to 34 years (mean 21.2 ± 0.2 years), and the number of premature ventricular contractions (PVCs) per day of observation ranged from 6,157 to 37,254 (mean 19,706 ± 656 PVCs). We registered the same parameters as in experimental arrhythmias but calculated them separately for mono- and polymorphic, left and right ventricular out-flow tract arrhythmias. The duration of follow-up of patients was up to 10 years. The endpoint was the detection or absence of cardiovascular and/or extracardiac pathology.Results. We recorded polymorphic PVCs and early monomorphic PVCs when modeling ventricular arrhythmias by the mechanism of delayed post-depolarization and early post-depolarization, respectively. Both early and late monomorphic PVCs were documented when inducing ventricular arrhythmias by re-entry. When modeling hydrogen peroxide-induced and strophanthin arrhythmias, we observed significantly higher values of PVC-QRS complex and ventricular arrhythmia internal deviation index in comparison with aconitine-induced arrhythmia. Favourable outcome was registered in 50.97% of patients, whilst coronary artery disease, arterial hypertension, and mitral valve prolapse were documented in 7.98%, 16.73% and 2.92% patients. The rest of the patients had gastrointestinal diseases. In patients with favourable outcome, the signs of monomorphic PVCs correlated with those revealed during the modeling of ventricular ectopy by early afterdepolarization (r = 0.92), whereas those signs of polymorphic PVCs correlated with those observed at barium chloride-induced delayed afterdepolarization (r = 0.94). In patients with CAD, signs of PVCs correlated with those registered during re-entry hydrogen peroxide-induced arrhythmia (r = 0.93), Finally, in patients with arterial hypertension and mitral valve prolapse signs of PVCs correlated with those documented at strophanthin-(r = 0.92) and adrenaline-induced delayed afterdepolarization (r = 0.89). In these patients, the values for both monomorphic and polymorphic PVCs, ventricular arrhythmia internal deviation index, duration of PVC-QRS complex and PVC-QRS/QRSaverage did not exceed 0.42 units, 149 ms and 1,44 units, respectively. The development of coronary artery disease and arterial hypertension well correlated with an increase in ventricular arrhythmia internal deviation index ≥ 0.56 units and QRS complex duration ≥ 157 ms. Mitral valve prolapse was associated with the duration of the QRS complex ≥ 159 ms of polymorphic PVCs.Conclusion. In patients with ventricular ectopy but without structural heart disease, an increase in the values of ventricular arrhythmia internal deviation index and the duration of PVC-QRS complex was ≥ 0.48 units and 149 ms, respectively, associated with the development of cardiovascular pathology. Development of coronary artery disease and hypertension correlated with ventricular arrhythmia internal deviation index ≥ 0.56 units, and QRS complex duration ≥ 157 ms in monomorphic and polymorphic PVCs, whereas development of mitral valve prolapse correlated QRS complex duration ≥ 159 ms in polymorphic PVCs.

Prognostic significance of quantitative electrocardiographic parameters in patients with non-high-risk pulmonary embolism

BackgroundElectrocardiogram (ECG) abnormalities indicating right ventricular strain have been reported to have prognostic value in severe cases of acute pulmonary embolism (PE). We aimed to analyze the prognostic significance of other quantitative ECG parameters in non-high-risk acute PE. MethodsConsecutive patients with non-high-risk acute PE were prospectively enrolled. The following baseline ECG parameters were collected: rhythm, heart rate, QRS axis, right bundle branch block (RBBB) pattern, S1Q3T3 pattern, T-wave inversion, ST-segment elevation, Qr in lead V1, PR Interval, QRS complex duration, QT interval, P-wave amplitude and duration, R- and S-wave amplitudes. The primary endpoint was early discharge within three days. Associations between ECG parameters and early discharge were analyzed. ResultsOverall, 383 patients were enrolled (median age: 67 years, 57% female): 277 (72.3%) with low-risk and 106 (27.7%) with intermediate-risk. The two groups of patients differed in several ECG signs of right ventricular strain and many other quantitative parameters like R- and S-wave amplitudes. In the multivariate logistic regression analysis, the S-wave depth in lead V5 (S-V5) was the only independent prognostic factor for early discharge (odds ratio = 0.137, 95% confidence interval = 0.031-0.613, p = 0.009). The optimum cutoff value of S-V5 for predicting early discharge derived from the receiver operative characteristic curve was 0.15 mv (c-statistic = 0.66, p =0.003). ConclusionsSeveral ECG signs of right ventricular strain and many other quantitative parameters were associated with disease severity in non-high-risk acute PE. An S-V5 lesser than 0.15 mv was predictive for early discharge in these patients.