QRS Time Research Articles

A novel formula to assess the QT interval in ventricular paced rhythm

Abstract Background QT interval measurement in the presence of right ventricular pacing (RVP) represents a clinical challenge due to altered ventricular activation resulting in a prolonged QT-interval. The aim of this study is to compare the QT interval in patients before and after ventricular pacing to develop a new formula for QT interval assessment in patients with RVP. Methods and results All patients presenting to our pacemaker clinic with single- or dual chamber device were included in this prospective observational study. Inclusion criteria were no permanent right ventricular stimulation, an intrinsic QRS interval of <120 ms, and ventricular rate >35 bpm and <150 bpm. Three 12-lead electrocardiograms were recorded for each patient: during intrinsic rhythm and 2 following an atrial paced and a ventricular paced QRS at the same rate. The intrinsic QRS and QT time/JT time (QTi/JTi) were measured during intrinsic and subsequent RVP. To obtain the formula, all measurements were performed on 100 patients (mean age 74 ± 11.3, male 33%) (RV apical lead 30% and non-apical lead 70%). Based on our measurements, a new formula QT (non-paced) = 139.23 + 0.55 xQT (paced) was derived. A population of 482 individuals (mean age 75.5±13.2 years (SD), 64% male) with permanent RV pacing were used as a validation group. The intrinsic QRS and QT time were measured during SR and subsequent RVP. To assess the relationship between the predicted QT with RVP and the measured QT without RVP, linear correlations analyses were performed. Our formula had a strong correlation with the irrespective QT without RVP (r=0.50) Conclusion We proposed a new simple formula to accurately estimate QT during RVP. This formula can be easily utilized in clinical practice. Figure 1: MAD characteristic value via plots stands for Median Absolute Difference (i.e. by how many ms the prediction is estimated on average). Figure 2: "Forest Plot" illustrates the correlation coefficients in the form of a forest plot. The dot r represents r and the bars the 95% confidence intervalsMAD characteristic value via plots standForest Plot" illustrates the correlation

Representative QRS loop of the VCG record evaluation.

Introduction: This study proposes an algorithm for preprocessing VCG records to obtain a representative QRS loop. Methods: The proposed algorithm uses the following methods: Digital filtering to remove noise from the signal, wavelet-based detection of ECG fiducial points and isoelectric PQ intervals, spatial alignment of QRS loops, QRS time synchronization using root mean square error minimization and ectopic QRS elimination. The representative QRS loop is calculated as the average of all QRS loops in the VCG record. The algorithm is evaluated on 161 VCG records from a database of 58 healthy control subjects, 69 patients with myocardial infarction, and 34 patients with bundle branch block. The morphologic intra-individual beat-to-beat variability rate is calculated for each VCG record. Results and Discussion: The maximum relative deviation is 12.2% for healthy control subjects, 19.3% for patients with myocardial infarction, and 17.2% for patients with bundle branch block. The performance of the algorithm is assessed by measuring the morphologic variability before and after QRS time synchronization and ectopic QRS elimination. The variability is reduced by a factor of 0.36 for healthy control subjects, 0.38 for patients with myocardial infarction, and 0.41 for patients with bundle branch block. The proposed algorithm can be used to generate a representative QRS loop for each VCG record. This representative QRS loop can be used to visualize, compare, and further process VCG records for automatic VCG record classification.

Electrocardiogram and cardiac electrophysiology characteristics of the premature ventricular contractions originating from right ventricular outflow tract

Premature ventricular contractions (PVCs) are a common type of irregular heartbeat (arrhythmia). PVCs often cause of symptoms that reduced quality of life such as: palpitation, pounding or jumping, chest pain, fatigue, blank beats or missed beats… Besides that, PVCs can produce ventricular tachycardia, which can lead to life-threatening hemodynamic instability.[1]
 Research objectives: Evalute the electrocardiogram and electrophysiology charaterics of the PVCs from right ventricular outflow tract. 
 Objects and research methods: Cross-sectional descriptive study of 145 patients.
 Research results: all patients had R waveform in: D2, D3, aVF and S wave dominant in: aVR, aVL; Transitional lead from V3-V5, in which transition in V4 accounts for the highest rate of 60.7%. The average QRS time is 136.3 ± 14.4 ms, almost all PVCs have time index of R < 0.5 and amplitude index of R < 0.3… There are 48.3% of patients with only negative component in lead D1; 40% of PVCs have notching at D2, D3, aVF. About cardiac electrophysiolpgy charateristics, for the origin of PVCs, he majority of PVCs in our study originated from the anterior wall of the right ventricular outflow tract with 64.8%; by superior-inferior position, mainly inferior region with 66.9%; according to septum - lateral position, mainly septal region with 72.4%. Most patients had PVCs originated from the inferior-anterior-septal region of the right ventricular outflow tract with 36.6%.

Time-related factors predicting a positive response to cardiac resynchronisation therapy in patients with heart failure

This study aimed to identify time parameters predicting favourable CRT response. A total of 38 patients with ischemic cardiomyopathy, qualified for CRT implantation, were enrolled in the study. A 15% reduction in indexed end-systolic volume after 6 months was a criterion for a positive response to CRT. We evaluated QRS duration, measured from a standard ECG before and after CRT implantation and obtained from mapping with NOGA XP system (AEMM); and the delay, measured with the implanted device algorithm (DCD) and its change after 6 months (ΔDCD); and selected delay parameters between the left and right ventricles based on AEMM data. A total of 24 patients presented with a positive response to CRT versus 9 non-responders. After CRT implantation, we observed differences between responders and non-responders group in the reduction of QRS duration (31 ms vs. 16 ms), duration of paced QRS (123 ms vs. 142 ms), and the change of ΔDCDMaximum (4.9 ms vs. 0.44 ms) and ΔDCDMean (7.7 ms vs. 0.9 ms). The difference in selected parameters obtained during AEMM in both groups was related to interventricular delay (40.3 ms vs. 18.6 ms). Concerning local activation time and left ventricular activation time, we analysed the delays in individual left ventricular segments. Predominant activation delay of the posterior wall middle segment was associated with a better response to CRT. Some AEMM parameters, paced QRS time of less than 120 ms and reduction of QRS duration greater than 20 ms predict the response to CRT. ΔDCD is associated with favourable electrical and structural remodelling.Clinical trial registration: SUM No. KNW/0022/KB1/17/15.

Left bundle branch area pacing: How to prevent a coronary venous fistula.

Left bundle branch area pacing: How to prevent a coronary venous fistula.

EPIDEMIOLOGY OF HYPERTENSION IN CROATIA (EHUH STUDY) -ECG FINDINGS AND CARDIOVASCULAR MORTALITY DATA AFTER 17 YEARS OF FOLLOW-UP

Objective: Our aim was to association of ECG findings and mortality data in random sample of Croatian population, an original cohort from the EHUH study after 17 years of follow up. Design and method: EHUH study is nation-wide survey on prevalence, treatment and control of hypertension in Croatia. In 2001–2003 a random sample of 1267 subjects were enrolled. Mortality data were analyzed after average period of 17 years. Office blood pressure (BP) was measured in sitting position using mercury sphygmomanometer three times at two visits and once at home visit: total 9 measurements -average BP values were calculated. Mortality data were collected from National Public Health Institute records. ECG scans were taken 17 years ago in 162 subjects and scans were analyzed by 2 different examiners manually, regardless one of another. In this group there were 17 deaths. Heart rate, intrinsic heart rate, RR interval, QT, TPe and QRS times, QTc and TPe/QTc ratios were analyzed across the groups. Results: Statistically significant differences were observed in distributions of intrinsic heart rate (p < 0.001) and QTc (p < 0.05) between subjects who died and survivors. Higher values of intrinsic heart rate were linked with lower mortality (B = -0.361, (p < 0.001). A smaller, but statistically significant difference was observed for QRS time (B = -0.045, p < 0.05) suggesting longer QRS times are linked with lower mortality. Conclusions: Our results which are not in line with other reports could be explained with small group, small number of events and most probably it is the case of reverse epidemiology.

Assesment of Normal ECG Percentiles and Cardiac Rhythm Problems through 12-Lead ECG Screening in School-Age Children

Introduction: Electrocardiography (ECG) is an important non-invasive examination used for the diagnosis of cardiovascular diseases and rhythm problems for nearly hundred years. Many studies showed the important effect of age and gender on electrocardiographic tracings and studies were made to form ECG data normal for age groups. The number of studies on this subject is quite low in children. The aim of this study was to evaluate the standard percentile values of ECG measurement and the prevalence of cardiac rhythm disorders in school children aged 6-18 in our region. Material and Method: 2154 students who were randomly selected from eight elementary, secondary and high schools in Malatya city center were included in the study and informed consent form was taken from their families. Using MAC 2000 (GE Healthcare, Milwaukee, USA) device capable of taking digital ECG record, ECG records with standard 12 derivations were taken for all participating children. ECG records of all children were examined by the same pediatric cardiologists. Using 24 hour Holter ECG and echocardiography, advanced evaluation was performed for the children with problems detected in ECG records. Results: Pathology was detected in the ECG of 110 out of a total of 2154 children whose ECG records were examined. Average age of 2044 children without detected conduction and rhythm disorder was 11.4±2.8 and 56.8% (n=1149) were female. In addition to the heart rate, PR, QT and QTc interval and QRS time, R/S ratio was also checked manually in V1, V2 and V6 precordial derivations together with QTc, P, QRS and T axis for the children participating in the study. These eleven parameters were compared to the other studies in literature. Mean QTc interval was detected below 440 milliseconds in all age groups (6-9, 9-13, 13-18). Mean heart rate per minute was found higher in all age groups in our study compared to other studies. Thus mean QTc interval was found lower than the other studies although QT distance was similar. Conclusion: Data of this study is important for the detection of normal ECG percentiles and the prevalence of rhythm problems in children and would guide other future studies on this subject.

Characteristics of myotonic dystrophy patients in the national registry of Japan

Myotonic dystrophies (DM) are inherited autosomal dominant disorders affecting multiple organs. Currently available therapeutics for DM are limited; therefore, a patient registry is essential for therapeutic development and success of clinical trials targeting the diseases. We have developed a nationwide DM registry in Japan under the Registry of Muscular Dystrophy (Remudy). The registration process was patient-initiated; however, physicians certified the clinical information. The dataset includes all Naarden and TREAT-NMD core datasets and additional items covering major DM clinical features. As of March 2020, we enrolled 976 patients with genetically confirmed DM. The majority (99.9%) of these patients had DM1, with 11.4% having the congenital form. However, 1 patient had DM2. Upon classifying 969 symptomatic DM1 patients based on their age at onset, an earlier onset was associated with a longer CTG repeat length. Myotonia was the most frequent symptom, followed by hand disability, fatigue, and daytime sleepiness. The frequency of hand disabilities, constipation, and visual disturbances was higher for patients with congenital DM. According to a multiple regression analysis of objective clinical measurements related to prognosis and activities of daily living, CTG repeat length strongly influenced the grip strength, forced vital capacity, and QRS time in an electrocardiogram. However, the grip strength was only modestly related to disease duration. This report will shed light on the Japanese national DM registry, which has recruited a significant number of patients. The registry will provide invaluable data for planning clinical trials and improving the standard of care for patients.

A new predictor for indicating clinical severity and prognosis in COVID-19 patients: Frontal QRS-T angle.

ObjectiveCOVID-19; It spread rapidly around the world and led to a global pandemic. Indicators of poor prognosis are important in the treatment and follow-up of COVID-19 patients and have always been a matter of interest to researchers. The aim of this study was to investigate the relationship between frontal QRS-T angle values and clinical severity and prognosis in COVID-19 patients.MethodsThis prospective case-control study was conducted with 130 COVID-19 patients whose diagnosis was confirmed by reverse transcriptase-polymerase chain reaction (RT-PCR) and 100 healthy controls. The CURB-65 score was used as the clinical severity score.ResultsA total of 130 patients and 100 healthy controls were included in the study. When the patient and control groups were compared a significant difference was found between QT (378.07 ± 33.75 vs. 368.63 ± 19.65, p < 0.001), QTc (410.79 ± 28.19 vs. 403.68 ± 11.70, p < 0.001), QRS time (95.04 ± 21.67 vs. 91.42 ± 11.08, p < 0.001) and frontal QRS-T angle (36.57 ± 22.86 vs. 22.72 ± 14.08, p < 0.001). According to clinical severity scoring, QT (370.27 ± 25.20 vs. 387.75 ± 40.19, p = 0.003), QTc (402.18 ± 19.92 vs. 421.48 ± 33.08, p < 0.001), frontal QRS-T angle (32.25 ± 18.79 vs. 41.94 ± 26.27), p = 0.0.16) parameters were found to be significantly different. Age (odds ratio [OR], 1.201; 95% confidence interval [CI], 1.111–1.298; p < 0.001) and frontal QRS-T angle ([OR], 1.045; 95% [CI], 1.015–1.075; p = 0.003) values were found to be an independent predictor for the severity of the disease. Frontal QRS-T angle ([OR], 1.101; 95% [CI], 1.030–1.176; p = 0.004), and CRP ([OR], 1.029; 95% [CI], 1.007–1.051; p = 0.01) parameters were found to be independent predictors for the mortality of the disease. As a mortality indicator; for the frontal QRS-T angle of ≥44.5°, specificity and sensitivity were 93.8% and 84.2%, respectively.ConclusionFrontal QRS-T angle can be used as a reproducible, convenient, inexpensive, new and powerful predictor in determining the clinical severity and prognosis of COVID-19 patients.

Comparison of electrophysiological characteristics of right- and left-sided Mahaim-type accessory pathways.

Mahaim-type accessory pathways (MAPs) are generally right-sided due to the embryological differentiation, but left-sided localization is also possible. This study aims to compare the clinical and electrophysiological characteristics of right- and left-sided MAPs. Of 251 patients diagnosed with AP by electrophysiological study between November 2015 and February 2020, 12 patients with MAP were included (right sided n = 8, left sided n = 4). MAP was diagnosed if; (1) no retrograde conduction; (2) anterograde decremental conduction; (3) adenosine sensitivity; and (4) Mahaim potential at successful ablation site were present. Ten of twelve MAPs were clustered on the lateral walls of the mitral (n = 3, 75%) and tricuspid annuli (n = 7, 87.5%). Right-sided MAPs were mostly long pathways extending toward the conduction system whereas left-sided MAPs were short extending toward the neighboring myocardium. For right- and left-sided APs, the median QRS times were 129 and 156 ms (p = .042), the median VAbl -RVApex intervals were -12 and 64 ms (p = .007), the median QRS-V(His) intervals were 16 and 86 ms (p = .120), and the median VAbl -QRS interval was -8 and 12 ms (p = .017), respectively. Coexistence of dual atrioventricular node physiology was observed only in right-sided APs (n = 3, 37.5%). MAPs are more typically located on the right but may rarely be seen on the left. Catheter ablation was associated with high success without complications.

Clinical variables improve efficacy of ECG scores to diagnose the left ventricular hypertrophy in general population

Abstract Left ventricular hypertrophy (LVH) is an important risk factor of various cardiovascular (CV) diseases and sudden death. Electrocardiography (ECG) is commonly used to detect LVH, but it has poor sensitivity, especially in high cardiovascular risk patients. Although echocardiography (ECHO) is a better, it is less available, and more expensive. Aim: To improve ECG scores to diagnose LVH in a general population. Methods The study was conducted in 2017–2019 in a representative sample of area residents. 717 volunteers randomly chosen from the local population were examined. Due to incomplete data, QRS complex duration ≥120ms, fascicular blocks, bundle branch blocks, paced rhythm, 216 people were excluded. Physical examination, ECG, ECHO and laboratory assessment were performed. In ECG LVH defined as &amp;gt;28mm for men, &amp;gt;20mm for women using Cornell index; &amp;gt;17mm for both sexes using Lewis index. In ECHO LV mass was calculated using the Devereux Formula and indexed by body surface area (left ventricular mass index – LVMI). The LVH was defined as LVMI ≥115 g/m2 for man and ≥95 g/m2 for women. Cardiovascular risk was calculated based on the ESC SCORE and additional risk categories published in the latest ESC guidelines. We analyzed 4 models to predict the probability of LVH at ECHO: Model 1: Cornell index; Model 2: Lewis index; Model 3: Cornel index + clinical parameters (age, sex, BMI, office BPs, QRS time, hs-TnT, and HbA1c); Model 4: Lewis index + clinical parameters (age, sex, BMI, office BPs, QRS time, hs-TnT, and HbA1c). Associations between LVH and clinical and biochemical variables were earlier analyzed using multiple linear regression models, these parameters were independently associated with LVH. Results A total of 501 patients were included. The average age of patients was 49.0±15.35 years, and 203 probants (40.5%) were male. We developed a novel score to assess the probability of LVH at ECHO in general population based on nine items (age, sex, body mass index, office BPs, Cornell index or Lewis index, QRS time, hs-TnT, and HbA1c). Additional clinical parameters improved sensitivity of Cornell index up to 86.0% (AUC:0.8011; 95% CI:0.748–0.854) from 64.9% (AUC:0.6450; 95% CI:0.573–0.716) in general population, to 92.9% (AUC:0.8423; 95% CI:0.760–0.924) from 64.3% (AUC:0.6481; 95% CI:0.518–0.779) in low CV risk patients, to 69.2% (AUC:0.6767; 95% CI:0.544–0.809) from 38.5% (AUC:0.5284; 95% CI:0.352–0.705) in moderate CV risk, and to 73.3% (AUC:0.7151; 95% CI: 0.609–0.821) of Lewis index from 50.0% (AUC: 0.5630; 95% CI:0.448–0.678) in high and very-high CV risk class. Conclusions Addition of clinical parameters to ECG indices in the diagnosis of LVH markedly improves their diagnostic efficacy both in general population and in higher risk groups. The new score may be useful in guiding the appropriateness of ECHO study in general population, and especially in moderate and high CV risk patients, who are not always aware of the increased CV risk. ROC curves for recognize LVH. Funding Acknowledgement Type of funding source: Public Institution(s). Main funding source(s): Medical University of Bialystok for Bialystok PLUS study

Cardiac involvement in a cross-sectional cohort of myotonic dystrophies and other skeletal myopathies.

AimsCardiac involvement in myopathies that primarily affect the skeletal muscle is variable and may be subtle, necessitating sensitive diagnostic approaches. Here, we describe the prevalence of cardiac abnormalities in a cohort of patients with skeletal muscle disease presenting at a tertiary care neuromuscular centre.Methods and resultsWe systematically investigated patients with skeletal myopathies and comprehensively analysed their cardiac phenotype including 24 h electrocardiogram, echocardiography with strain analyses, contrast‐enhanced cardiac magnetic resonance imaging, and, if at increased risk of coronary artery disease, computed tomography coronary angiography. We prospectively screened 91 patients with diverse skeletal myopathies and enrolled 73 patients. The most pronounced cardiac involvement was present in patients with dystrophic myopathies (cardiac abnormalities in 59% of patients). We analysed myotonic dystrophies (n = 29) in more detail and found prolonged QRS (99.4 ± 15.6 vs. 91.5 ± 10.3 ms; P = 0.027) and QTc times (441.1 ± 28.1 vs. 413.0 ± 23.3 ms; P < 0.001) and increased left atrial size (27.28 ± 3.9 vs. 25.0 ± 3.2 mm/m2; P = 0.021) when compared with healthy controls. Left ventricular systolic function was reduced (ejection fraction < 55%) in 31% of myotonic dystrophies, while only 4% had an ejection fraction < 50%. Apical peak systolic longitudinal strain was slightly reduced (P = 0.023).ConclusionsScreening for cardiac involvement in the skeletal muscle disease seems prudent particularly in patients with dystrophic myopathies. In the subset of myotonic dystrophy patients, QRS and QTc times as well as myocardial strain may be useful parameters. Their potential for predicting cardiac adverse events needs further evaluation.

Evaluation of index of cardiac-electrophysiological balance as arrhythmia predictor in bonsai users.

Synthetic cannabinoids are part of a group of drugs called new psychoactive substances. The increase in substance use among young adults is becoming a major problem in the world. In this study we aimed to investigate the effects of synthetic cannabinoid drugs such as bonsai to electrocardiographic (ECG) parameters, in patients who were admitted to emergency service with self-reported usage of bonsai. Seventy-two patients (68 males; mean age 33.8±11.8) with self-reported use of bonsai and 27 (22 males; mean age 37.1±8.7) age and sex-matched healthy control group enrolled the study. ECG parameters and rhythm holter were measurements calculated in both groups. Groups were age and sex matched. Glucose, potassium, white blood cell count, heart rate end smoking status was significantly different in patients compared to control group. P wave max time, P wave min. time, P wave dispersion, QT max. time QT dispersion, QT corrected time and index of cardiac-electrophysiological balance measurements (iCEB) were significantly different in groups of patients. A multivariate logistic regression analysis was used to determine independent predictors of ≥30 Ventricular premature beat (VPB)/h using parameters found to be associated with ≥30 VPB/h in a univariate analysis (potassium, QT<inf>max</inf> time, QTc, QRS time, iCEB).In a multivariate analysis, independent predictors of ≥30 VPB/h were potassium (Odds ratio [OR]: 0.107, 95% CI: 0.024-0.481;P=0.004) and iCEB (OR: 4.474, 95% CI: 1.752-11.429;P=0.002). In generalize linear model β-coefficient value of interaction terms between K*iCEB has no important effect on ventricular premature beats. If the results are confirmed in further studies, iCEB seems to be a simple, easily measurable and non-invasive marker to predict cannabinoid-induced ventricular arrhythmias.

Investigation of changes in electrocardiography before and after free diving

Aim: To evaluate the electrocardiographic (ECG) parameters and hemodynamic parameters in predicting the development of arrhythmias after free diving static apnea performance and maximum breath hold. Material and Methods: Twenty-four volunteer athletes participating in the free diving competition in 2015 (19 males (79.2%) and 5 females (20.8%)) were included in the study. Peripheral O2 saturation (SpO2), heart rate (HR), ECG parameters (PR interval, QRS time, T wave amplitude, corrected QT time, presence of bandle branch block and new bandle branch block development, atrial premature beats, ventricular premature beats) were analyzed. Results: There was no statistically significant difference between before static apnea measurements (systolic blood pressure (SBP) 124.7 ± 10.8 mmHg, diastolic blood pressure (DBP) 76.5 ± 6.7 mmHg, heart rate (HR) 80.2 ± 13.4 beats / min, SpO2 97.1 ± 0.9%) and after performance (SBP 128.8 ± 13.6 mmHg DBP 78.0 ± 5.9 mmHg, HR 85.8, ± 16.5 beats / min and SpO2 96.7 ± 2.3%)(p = 0.175; p = 0.334; p = 0.104; p = 0.336, respectively). Conclusion: No significant changes were observed in ECG parameters, heart rate, saturation and blood pressure values evaluated after static apnea performance. These findings can be used to support that the risk of arrhythmia during static apnea does not persist after apnea has ended.

The relationship between electrocardiographic data and mortality in children diagnosed with dilated cardiomyopathy.

The mortality causes of patients followed up due to dilated cardiomyopathy (DCM) include complications related to heart failure, ventricular arrhythmia, and transplantation. This study aims to evaluate the electrocardiographic findings of patients diagnosed with dilated cardiomyopathy and determine its relationship with mortality. The electrocardiographic, clinical, and laboratory findings of patients diagnosed with dilated cardiomyopathy between January 1, 2012, and September 1, 2018, in our university's pediatric cardiology department were retrospectively evaluated. The electrocardiographic findings of surviving and exitus dilated cardiomyopathy patients were compared and their effect on mortality was investigated. Twelve of the total 85 patients diagnosed with dilated cardiomyopathy were deceased. According to the electrocardiographic findings of surviving and exitus patients, there was a statistically significant difference in terms of P maximum (Pmax), P dispersion (Pdis), QT dispersion (QTdis), QTc maximum (QTcmax), QTc dispersion (QTcdis), Tp-e maximum (Tp-emax), Tp-e dispersion (Tp-edis), and QRS time. Hypertrophy and ischemia findings of electrocardiography were also statistically significant. There was a statistically significant difference between the two groups according to the echocardiographic findings of left ventricular ejection fraction (LVEF), left ventricular shortening fraction (LVSF), left ventricular end-diastolic diameter (LVEDd), and left ventricular end-systolic diameter (LVESd) measurements. It is well known that children diagnosed with dilated cardiomyopathy are at greater risk of arrhythmia compared with normal children. Although previous studies have determined the relationship between mortality and a limited number of electrocardiographic findings, especially in adults, the relationship between electrocardiography findings of children diagnosed with DCM and mortality has not been investigated before in such detail, as in our study.Conclusion: In this study, the significant difference between the electrocardiographic data of deceased and surviving dilated cardiomyopathy patients suggests that electrocardiographic data should be evaluated in detail in order to determine the low and high risk of mortality in patients with dilated cardiomyopathy.What is Known:• Previous studies on the relationship between limited electrocardiography data of adult patients diagnosed with DCM and mortality have been determinedWhat is New:• ECG data has not been investigated in such detail in child DCM patients, as in our study.

Contemporary epidemiology and treatment of hospitalized heart failure patients in real clinical practice in China

Objective: To observe the etiology, comorbidities, clinical features and treatment patterns of hospitalized patients with heart failure (HF) in China. Methods: Data were collected prospectively on hospitalized patients with HF who were enrolled in China Heart Failure Center Registry Study from 169 participating hospitals from January 2017 to August 2018. In this cross-sectional study, patients were stratified by left ventricular ejection fraction (LVEF) category: heart failure with reduced ejection fraction (HFrEF, LVEF<40%); heart failure with mid-ranged ejection fraction (HFmrEF, 40%≤LVEF<50%) and heart failure with preserved ejection fraction (HFpEF, LVEF≥50%). The clinical data were collected, including demographic information, diagnosis, signs, electrocardiogram, echocardiography, laboratory tests, and treatment. Results: A total of 31 356 hospitalized patients with HF were included, 19 072 (60.8%) were males and the average age was (67.9±13.6) years old. The common causes of HF were hypertension (57.2%), coronary heart disease (54.6%), dilated cardiomyopathy (14.7%), valvular heart disease (9.2%). The common complications were atrial fibrillation/atrial flutter (34.1%), diabetes (29.2%), and anemia (26.7%). 32.8% of patients had a history of hospitalization for HF within the previous 12 months. There were 11 034 (35.2%) patients with HFrEF, 6 825 (21.8%) patients with HFmrEF and 13 497 (43.0%) patients with HFpEF. Compared with patients with HFpEF, patients with HFrEF had a lower systolic blood pressure ((124.7±21.1)mmHg(1 mmHg=0.133 kPa) vs. (134.9±22.9)mmHg), faster heart rate ((85±19) beats/minutes vs. (81±19)beats/minutes), and higher percentage of New York Heart Association (NYHA) class Ⅳ, smoking, alcohol, left bundle branch block, and QRS time≥130 ms, and higher levels of blood uric acid, BNP, and NT-proBNP (all P<0.05). Compared with patients with HFmrEF and HFrEF, patients with HFpEF were older, more women, and higher comorbidity burden including hypertension, atrial fibrillation/atrial flutter, anemia and chronic obstructive pulmonary disease (all P<0.05). HFmrEF took a mid-position between HFrEF and HFpEF in age, gender, heart rate, systolic blood pressure, hypertension, atrial fibrillation/atrial flutter, anemia, and chronic obstructive pulmonary disease (all P<0.05). Patients with HFmrEF had the highest proportion of coronary heart disease, myocardial infarction and percutaneous coronary intervention (all P<0.05). During hospitalization, loop diuretics were used in 90.2% of patients, and intravenous inotropics were used in 20.4% of patients. The use of ACEI/ARB/ARNI, β blockers and aldosterone receptor antagonists at discharge were 71.8%, 79.1% and 83.6% in HFrEF and 69.9%, 75.5% and 72.4% in HFmrEF, respectively. The use of digoxin at discharge was 25.3% (HFrEF 36.7%, HFmrEF 23.1%, HFpEF 17.0%). The rates of cardiac resynchronization therapy and implantable cardioverter defibrillator in HFrEF were 2.7% and 2.1%. Conclusions: Among the hospitalized patients with HF in China, coronary heart disease and hypertension are the mostly prevalent causes. HFpEF accounts for a large proportion of hospitalized patients with HF. HFrEF, HFmrEF and HFpEF have different etiology and clinical features. In real-world, there are still large gaps in the effective application of the guideline recommended therapies to HF patients, especially the non-pharmacological therapy option, which needs to be improved further in China.

Shorter time to begin of QRS fragmentation predicts non-response to cardiac resynchronization therapy in non-ischemic heart failure patients

ObjectiveCardiac resynchronization therapy (CRT) is an effective option in the treatment of patients with heart failure and wide QRS. Presence of fragmented QRS (f-QRS) on 12-lead electrocardiogram (ECG) has been shown to be associated with non-response to CRT. The aim of this study was to evaluate whether onset of fragmentation (Q-f interval) is important for CRT response. MethodsThis is a single-center retrospective analysis of prospectively collected data of 38 non-ischemic dilated cardiomyopathy patients (18 men, mean age 63±12 years) with f-QRS on 12-lead ECG who underwent CRT. Duration of fragmentation, ratio of f-QRS duration to the total QRS duration (f-QRS/t-QRS ratio) and time interval from Q wave to the onset of QRS fragmentation (Q-f interval) were measured. ResultsThe baseline clinical, echocardiographic findings of patients with responders (24 patients, 63%) and non-responders showed no statistically significant difference, except for longer f-QRS duration, increased ratio of f-QRS duration to the total QRS duration (f-QRS/t-QRS ratio) and shorter time interval from Q wave to the onset of QRS fragmentation (Q-f interval) in patients not responding to CRT. In multivariate analysis, Q-f interval was determined as an independent predictor of response to CRT (OR 1.240, 95% CI: 1.049–1.467, p=.012). In ROC curve analysis, the best cut-off value for Q-f interval to predict responders was 32.5ms with a sensitivity and specificity of 83.3% and 85.7%, respectively (AUC 0.899, 95% CI: 0.797–1.000, p=.001). ConclusionsShorter time from onset of QRS to beginning of fragmentation is a simple ECG marker to predict non-responsive patients to CRT.

El inicio rápido de la fragmentación del QRS predice la no respuesta a la terapia de resincronización cardíaca en pacientes con insuficiencia cardíaca no isquémica

ObjectiveCardiac resynchronization therapy (CRT) is an effective option in the treatment of patients with heart failure and wide QRS. Presence of fragmented QRS (f-QRS) on 12-lead electrocardiogram (ECG) has been shown to be associated with non-response to CRT. The aim of this study was to evaluate whether onset of fragmentation (Q-f interval) is important for CRT response. MethodsThis is a single-center retrospective analysis of prospectively collected data of 38 non-ischemic dilated cardiomyopathy patients (18 men, mean age 63±12 years) with f-QRS on 12-lead ECG who underwent CRT. Duration of fragmentation, ratio of f-QRS duration to the total QRS duration (f-QRS/t-QRS ratio) and time interval from Q wave to the onset of QRS fragmentation (Q-f interval) were measured. ResultsThe baseline clinical, echocardiographic findings of patients with responders (24 patients, 63%) and non-responders showed no statistically significant difference, except for longer f-QRS duration, increased ratio of f-QRS duration to the total QRS duration (f-QRS/t-QRS ratio) and shorter time interval from Q wave to the onset of QRS fragmentation (Q-f interval) in patients not responding to CRT. In multivariate analysis, Q-f interval was determined as an independent predictor of response to CRT (OR 1.240, 95% CI: 1.049-1.467, P=.012). In ROC curve analysis, the best cut-off value for Q-f interval to predict responders was 32.5ms with a sensitivity and specificity of 83.3% and 85.7%, respectively (AUC 0.899, 95% CI: 0.797-1.000, P=.001). ConclusionsShorter time from onset of QRS to beginning of fragmentation is a simple ECG marker to predict non-responsive patients to CRT.

Extrasístoles ventriculares: relación deflexión intrinsecoide / QRS para discriminar el origen

Introducción: las taquicardias ventriculares (TV) y complejos ventriculares prematuros (CVP) de los tractos de salida (TS) son arritmias ventriculares más frecuentes que se producen en el corazón estructuralmente sano. El manejo intervencionista con ablación es el tratamiento que en casos seleccionados ha demostrado tener mayor efectividad terapéutica; para optimizar el lugar de ablación sobre el foco de origen se han conformado ayudas complementarias a los estudios de extensión. Objetivo: proponer una herramienta para discriminar tempranamente el origen de las extrasístoles ventriculares provenientes de los tractos de salida a partir del cálculo del valor de la relación deflexión intrinsecoide/QRS medida en extrasístoles ventriculares en V6. Materiales y métodos: se realizó un estudio de corte transversal, en pacientes con diagnóstico de CVP llevados a estudio electrofisiológico más ablación exitosa. Se midió la deflexión intrinsecoide y se relacionó con el tiempo total del QRS en V6. Resultados: a partir de los análisis de los puntos del corte se estableció un valor de la relación deflexión intrisecoide/qrs menor o igual a 0.67 para el ventrículo derecho y mayor o igual a o.68 para el ventrículo izquierdo. El análisis de los datos registró una correcta clasificación de los pacientes en el 80% de los casos. Conclusiones: este estudio propone una herramienta corta y sencilla de aplicar, que intenta predecir el origen de estas arritmias a partir de unas mediciones realizadas en un electrocardiograma en que se muestre dicha extrasístole ventricular en V6, en donde es obtener posible origen del foco arritmogénico antes del procedimiento intervencionista.

Mild hypothermia (33°C) increases the inducibility of atrial fibrillation: An in vivo large animal model study.

Application of therapeutic mild hypothermia in patients after resuscitation, often accompanied by myocardial infarction, cardiogenic shock, and systemic inflammation may impact on cardiac rhythm. We therefore tested susceptibility to atrial arrhythmias during hyperthermia (HT, 40.5°C), normothermia (NT, 38.0°C), and mild hypothermia (MH, 33.0°C). Nine healthy, anesthetized closed-chest landrace pigs were instrumented with a quadripolar stimulation catheter in the high right atrium and a decapolar catheter in the coronary sinus. Twelve-lead surface electrograms were recorded and core body temperature was altered to HT, NT, and MH using external warming or intravascular cooling. Repetitive measurements of effective atrial refractory period (AERP), atrial fibrillation (AF) inducibility, and electrocardiogram (ECG) parameters at different heart rates were performed. During MH, AERP was significantly longer while the inducibility of AF was significantly higher compared to NT and HT (median [range]: HT 18 (0, 80)%; NT 25 (0, 80)%; MH 68 (0, 100)%; P<0.05 MH vs NT+HT). Mean AF duration did not differ between groups. Arterial potassium levels decreased with falling temperatures (HT: 4.2±0.1mmol/L; NT: 4.0±0.2mmol/L; MH: 3.5±0.1mmol/L; P<0.001). Surface ECGs during MH showed reduced spontaneous heart rate (HT: 99±13beats/min; NT: 87±15beats/min; MH: 66±10beats/min; P<0.05), increased PQ, stim-Q, and QT intervals (P<0.01) but no change in QRS duration or time from peak to end of the T wave interval. Our data imply that MH represents an arrhythmic substrate rendering the atria more susceptible to AF although conduction times as well as refractory periods are increased. Further investigations on potential electrophysiological limits of therapeutic cooling in patients are required.