Fragmented QRS complex could predict all-cause mortality in patients with connective tissue disease-associated pulmonary arterial hypertension.

OBJECTIVES: To investigate the prognostic impact and pathophysiological characteristics of fragmented QRS complex (fQRS) on patients with connective tissue disease-associated pulmonary arterial hypertension (CTD-PAH). METHODS: This was a multicentre retrospective study recruiting 141 patients with CTD-PAH diagnosed by right heart catheterization (114 cases in the discovery cohort and 27 cases in the validation cohort). fQRS and ST-T change were detected on conventional 12-lead electrocardiogram (ECG). Patients were followed up every 3 months to update their status and the primary end point was all-cause death. Clinical information and ECG characteristics were compared between survival and death groups and Kaplan-Meier curve was used for survival analysis. RESULTS: There were significant differences in age, gender, 6-min walk distance, NT-proBNP, WHO class, presence of fQRS and presence of ST-T change in inferior leads between survival group and death group. Inferior fQRS and ST-T change were significantly associated with right ventricular (RV) dilatation and reduced RV ejection fraction (RVEF). Kaplan-Meier curve showed that all-cause mortality was higher in CTD-PAH with fQRS (p= 0.003) and inferior ST-T change (p= 0.012). Low- and intermediate-risk CTD-PAH with inferior ST-T change had higher all-cause mortality (p= 0.005). The prognostic value of fQRS and inferior ST-T change was validated in external validation cohort. CONCLUSION: The presence of inferior fQRS and ST-T change could predict poor prognosis in CTD-PAH. CLINICAL TRIAL REGISTRATION NUMBER: NCT05980728, https://clinicaltrials.gov.

Paced QRS morphology mimicking complete left bundle branch block induced by right ventricular pacing is associated with pacing-induced cardiomyopathy.

INTRODUCTION: Right ventricular (RV) pacing sometimes causes left ventricular (LV) systolic dysfunction, also known as pacing-induced cardiomyopathy (PICM). However, the association between specifically paced QRS morphology and PICM development has not been elucidated. This study aimed to investigate the association between paced QRS mimicking a complete left bundle branch block (CLBBB) and PICM development. METHODS: We retrospectively screened 2009 patients who underwent pacemaker implantation from 2010 to 2020 in seven institutions. Patients who received pacemakers for an advanced atrioventricular block or bradycardia with atrial fibrillation, baseline LV ejection fraction (LVEF) ≥ 50%, and echocardiogram recorded at least 6 months postimplantation were included. The paced QRS recorded immediately after implantation was analyzed. A CLBBB-like paced QRS was defined as meeting the CLBBB criteria of the American Heart Association/American College of Cardiology Foundation/Heart Rhythm Society in 2009. PICM was defined as a ≥10% LVEF decrease, resulting in an LVEF of <50%. RESULTS: Among the 270 patients analyzed, PICM was observed in 38. Baseline LVEF was lower in patients with PICM, and CLBBB-like paced QRS was frequently observed in PICM. Multivariate analysis revealed that low baseline LVEF (odds ratio [OR]: 0.93 per 1% increase, 95% confidence interval [CI]: 0.89-0.98, p = 0.006) and CLBBB-like paced QRS (OR: 2.69, 95% CI: 1.25-5.76, p = 0.011) were significantly associated with PICM development. CONCLUSION: CLBBB-like paced QRS may be a novel risk factor for PICM. RV pacing, which causes CLBBB-like QRS morphology, may need to be avoided, and patients with CLBBB-like paced QRS should be followed-up carefully.

Pilot study to evaluate left-to-right ventricular offset in biventricular pacing-comparison of electrocardiographic imaging and ECG.

INTRODUCTION: Biventricular pacing (BiVp) improves outcomes in systolic heart failure patients with electrical dyssynchrony. BiVp is delivered from epicardial left ventricular (LV) and endocardial right ventricular (RV) electrodes. Acute electrical activation changes with different LV-RV stimulation offsets can help guide individually optimized BiVp programming. We sought to study the BiVp ventricular activation with different LV-RV offsets and compare with 12-lead ECG. METHODS: In five patients with BiVp (63 ± 17-year-old, 80% male, LV ejection fraction 27 ± 6%), we evaluated acute ventricular epicardial activation, varying LV-RV offsets in 20 ms increments from -40 to 80 ms, using electrocardiographic imaging (ECGI) to obtain absolute ventricular electrical uncoupling (VEUabs, absolute difference in average LV and average RV activation time) and total activation time (TAT). For each patient, we calculated the correlation between ECGI and corresponding ECG (3D-QRS-area and QRS duration) with different LV-RV offsets. RESULTS: The LV-RV offset to attain minimum VEUabs in individual patients ranged 20-60 ms. In all patients, a larger LV-RV offset was required to achieve minimum VEUabs (36 ± 17 ms) or 3D-QRS-area (40 ± 14 ms) than that for minimum TAT (-4 ± 9 ms) or QRS duration (-8 ± 11 ms). In individual patients, 3D-QRS-area correlated with VEUabs (r 0.65 ± 0.24) and QRS duration correlated with TAT (r 0.95 ± 0.02). Minimum VEUabs and minimum 3D-QRS-area were obtained by LV-RV offset within 20 ms of each other in all five patients. CONCLUSIONS: LV-RV electrical uncoupling, as assessed by ECGI, can be minimized by optimizing LV-RV stimulation offset. 3D-QRS-area is a surrogate to identify LV-RV offset that minimizes LV-RV uncoupling.

LBBB and heart failure-Relationships among QRS amplitude, duration, height, LV mass, and sex.

BACKGROUND: Height, left ventricular (LV) size, and sex were proposed as additional criteria for patient selection for cardiac resynchronization therapy (CRT) but their connections with the QRS complex in left bundle branch block (LBBB) are little investigated. We evaluated these. METHODS: Among patients with "true" LBBB, QRS duration (QRSd) and amplitude, and LV hypertrophy indices, were correlated with patient's height and LV mass, and compared between sexes. RESULTS: In this study cohort (n = 220; 60 ± 12 years; left ventricular ejection fraction [LVEF] 21 ± 7%; mostly New York Heart Association II-III, QRSd 165 ± 19 ms; 57% female; 70% responders [LVEF increased ≥5%]), LV mass was increased in all patients. QRS amplitude did not correlate with LV mass or height in any individual lead or with Sokolow-Lyon or Cornell-Lyon indices. QRSd did not correlate with height. In contrast, QRSd correlated strongly with LV mass (r = .51). CRT response rate was greater in women versus men (84% vs. 58%, p < .001) despite shorter QRSd [7% shorter (p < .0001)]. QRSd normalized for height resulted in a 2.7% and for LV mass 24% greater index in women. CONCLUSION: True LBBB criteria do not exclude HF patients with increased LV mass. QRS amplitudes do not correlate with height or LV mass. Height does not affect QRSd. However, QRSd correlates with LV size. QRSd normalized for LV mass results in 24% greater value in women in the direction of sex-specific responses. LV mass may be a significant nonelectrical modifier of QRSd for CRT.

Narrow QRS ectopy with concealed connections from a para-Hisian origin to the proximal left fascicles.

INTRODUCTION: Catheter ablation of ectopy originating from the vicinity of the His bundle can be challenging. METHODS AND RESULTS: We report a case of a 33-year-old man with narrow QRS ectopy with preferential conduction from a para-Hisian origin to the proximal left fascicles, which was successfully eliminated by radiofrequency ablation in the right coronary cusp, guided by ultrahigh-resolution mapping of the His bundle, bundle branch, and fascicular electrograms. CONCLUSION: Some narrow QRS ectopy may originate from the vicinity of the conduction system, instead of the "true" conduction system, and have concealed connections from its origin to the conduction system.

Pacemaker-Related Factors and Outcomes of Fontan Patients　- Impact of Paced QRS Duration.

BACKGROUND: Permanent pacemaker (PPM) implantation has been identified as a risk factor for morbidity and mortality after Fontan operation. This study investigated the factors associated with outcomes in patients with Fontan physiology who underwent PPM implantation. METHODS AND RESULTS: We retrospectively reviewed 508 patients who underwent Fontan surgery at Asan Medical Center between September 1992 and August 2022. Of these patients, 37 (7.3%) received PPM implantation. Five patients were excluded, leaving 32 patients, of whom 11 were categorized into the poor outcome group. Poor outcomes comprised death, heart transplantation, and "Fontan failure". Clinical, Fontan procedure-related, and PPM-related factors were compared between the poor and good outcome groups. Ventricular morphology, Fontan procedure-associated factors, pacing mode, high ventricular pacing rate, and time from first arrhythmia to PPM implantation did not differ significantly between the 2 groups. However, the poor outcome group exhibited a significantly longer mean paced QRS duration (P=0.044). Receiver operating characteristic curve analysis revealed a paced QRS duration cut-off value of 153 ms with an area under the curve of 0.73 (P=0.035). CONCLUSIONS: A longer paced QRS duration was associated with poor outcomes, indicating its potential to predict adverse outcomes among Fontan patients.

Tighter is better: Can a simple and cost-free parameter predict response to cardiac synchronization therapy?

BACKGROUND: Several studies have evaluated the role of QRS duration (QRSd) or QRS narrowing as a predictor of response to cardiac resynchronization therapy (CRT) to reduce nonresponders. AIM: Our study aimed to determine the correlation between the relative change in QRS index (QI) compared to clinical outcome and prognosis in patients who underwent CRT implantation. METHODS: A three-centers study involving 398 patients with a CRT device was conducted. Clinical, echocardiographic and pharmacological variables, QRSd before and after CRT implantation and QI were measured. RESULTS: In a 6-month follow-up, a significant improvement in left ventricular ejection fraction (LVEF), left ventricular end-diastolic and systolic volumes (LVEDV and LVESV) were observed. QI was related to reverse remodeling (multiple r-squared: 0.48, adjusted r-squared: 0.43, p = .001), and the cut-off value that best predicted LV reverse remodeling after 6 months of CRT was 12.25% (AUC 0.7, p = .001). At 24 months, a statistically significant difference was found between patients with a QI ≤ 12.25% and those with a QI > 12.25% regarding NYHA class worsening (p = .04). The mean of the QI of patients who died from cardiovascular causes was lower than patients who died of other causes (p = .0179). A correlation between pre-CRT QRSd/LVEDV and QI was observed (r = + 0.20; p = .0003). A higher QRSd/LVEDV ratio was associated with an improved LVEF, LVEDV, and LVESV (p < .0001) at follow-up. CONCLUSIONS: QI narrowing after CRT was related to greater echocardiographic reverse remodeling and a lower rate of adverse events (death or cardiovascular hospitalizations). The QI can improve the prediction of adverse events in a population with CRT regardless of comorbidities according to the Charlson Comorbidity Index. QI could be used to predict CRT response.

Can the QRS morphology of outflow tract ventricular arrhythmia change when right bundle branch block emerges during sinus rhythm?

BACKGROUND: QRS morphology can change during ventricular arrhythmias (VAs) with the appearance of bundle branch block (BBB). METHODS: We retrospectively investigated 195 consecutive patients who underwent an initial ablation of VA. The study inclusion criteria were VAs that were successfully ablated in the outflow tract (OT) and in whom right bundle branch block (RBBB) was induced by catheter manipulation close to the His bundle area during sinus rhythm, before any radiofrequency application. We analyzed the QRS morphology of the VAs with and without RBBB during sinus beats. RESULTS: Twenty-four patients (age 59 ± 17 years, female 14) developed RBBB at some point during their procedure. The successful ablation sites of the VAs were the right ventricular outflow tract (RVOT) in 12 patients, pulmonary artery in one, left coronary cusp in five, right coronary cusp in three, right-left cusp junction in two, and great cardiac vein in two. QRS-morphology change was observed in five (20%) cases. The successful ablation sites in that group were the left coronary cusp in three cases, right coronary cusp in one, and RVOT septum in one. The QRS duration of the VAs increased during RBBB. CONCLUSIONS: There are some cases of OT-VAs in which the QRS waveform changes with the appearance of catheter induced RBBB. We need to be aware that when QRS morphology changes during an OT-VA ablation, it does not necessarily mean that the origin or exit of the VA has changed.

Different methods of 3D QRS area calculation from vectorcardiographic X, Y, and Z Leads.

3DQRSarea is a strong marker for cardiac resynchronization therapy and can be obtained by taking the (i) summation or the (ii) difference of the areas subtended by positive and negative deflections in X, Y, Z vectorcardiographic electrocardiogram (ECG) leads. We correlated both methods with the instantaneous-absolute-3D-voltage-time-integral (VTIQRS-3D). 3DQRSarea consistently underestimated the VTIQRS -3D, but the summation method was a closer and more reliable approximation. The dissimilarity was less apparent in left bundle branch block (r2 summation .996 vs. difference .972) and biventricular paced ECGs (r2 .996 vs. .957) but was more apparent in normal ECGs (r2 .988 vs. .653).

Analysis of QRS complex morphology in children and adolescents with obstructive sleep apnea syndrome.

Obstructive sleep apnea syndrome (OSAS) leads to many cardiovascular, neurologic, metabolic, and neurocognitive consequences. Conduction deficits, deviations in electrical axis, and changes in QRS morphology reflect the impairments in cardiac muscle activity and underlie the cardiovascular complications of OSAS. Here we aimed to determine the relationship between OSAS and changes in the cardiac conduction system in children and adolescents. During the 6-month duration of the study, all children having the diagnosis of OSAS in Sleep and Disorders Unit following a full-night polysomnography (PSG) were consecutively evaluated. ECGs were performed and analyzed in the Division of Pediatric Cardiology, Department of Pediatrics. The maximum spatial vector size (QRSmax), QRS electrical axis (EA), left and right ventricular hypertrophy, and the presence of fragmented QRS (fQRS) or prolonged R or S wave were examined in detail. A total of 17 boys with OSAS and 13 healthy boys participated in the study. The mean QRSmax and the QRSmax on V5 derivative were significantly lower in the patient group compared to those in the control group (p = 0.011 and p = 0.017, respectively). EA was similar between the two groups. While none of the patients with OSAS nor the control group had left ventricular hypertrophy, only one boy with OSAS had right ventricular hypertrophy according to ECG-derived analysis. The percentage of fQRS or notched R or S waves was significantly higher in patients with OSAS compared to healthy controls (p = 0.035), especially in children below the age of 5 years (p = 0.036).  Conclusion: This study demonstrated that male children and adolescents with OSAS have a combination of QRS complex changes characterized by low QRS voltages, and increased frequency of fragmented QRS. These findings reflect that the electrical remodeling and structural remodeling of the myocardium are considerably affected by OSAS in children and adolescents, leading to ventricular changes and intraventricular conduction problems. What is Known: • Pediatric obstructive sleep apnea syndrome (OSAS) characterized by recurrent intermittent hypoxemia, hypercapnia, and sleep fragmentation results in sympathetic nervous system activation, increased inflammation, and hypoxic endothelial dysfunction. When left untreated, OSAS leads to many cardiovascular, neurologic, metabolic and neurocognitive consequences, and also to sudden infant death syndrome in young children, probably due to the involvement of the cardiac conduction system. What is New: • This study demonstrated that mean QRSmax was significantly lower in male children and adolescents with OSAS, reflecting the structural and electrical remodeling of the myocardium, and one boy with OSAS had RVH according to ECG-derived analysis. The percentage of fQRS or notched R or S waves was much higher in boys with OSAS, especially in children below the age of five years. These finding showed that myocardium was considerably affected to impair the intraventricular conduction in younger children with OSAS.

Assessment of QRS duration and presence of fragmented QRS in patients with celiac disease.

Background: Celiac Disease (CD) is characterized by small intestine involvement. However, cardiac manifestations may also be seen in the clinical course. The significance of the QRS prolongation and the presence of QRS fragmentation (fQRS) has been previously studied in many chronic inflammatory disorders as an independent predictor of cardiac manifestations. The study aimed to evaluate the QRS duration and presence of fQRS in patients with CD. Methods: 164 patients with CD and 162 healthy controls were included in the present study. QRS duration and presence of fQRS were calculated from the 12-lead electrocardiogram and compared between groups. The association between these parameters and disease duration was also evaluated. Results: QRS duration was found to be higher in the CD group compared to the control group (83 (76.8-93) vs. 91 (84-94), p<0.001). The presence of fQRS was demonstrated to be higher in the CD group (n=68 (41.5%) vs n=42 (25.9%), p=0.003). Notably, QRS duration was positively correlated with disease duration (Spearman's Rho= 0.47, p<0.001). In addition, disease duration was significantly higher in the fQRS (+) group (60 (23,5-144) vs. 28,5 (15-71,5), p=0.002). Conclusion: This study revealed that QRS prolongation and the presence of fQRS were higher in patients with CD. The presence of these findings may be an indicator of early subclinical cardiac involvement, especially in those with long disease duration. Thus, patients with these ECG findings can be considered for further cardiac evaluation.

Evaluation of QRS duration and presence of fragmented QRS in patients with inflammatory bowel disease.

Background: Inflammatory Bowel Disease (IBD) is mostly characterized by gastrointestinal tract involvement, however can also be accompanied with cardiac manifestations. QRS prolongation and the presence of QRS fragmentation (fQRS) have been previously evaluated in many chronic inflammatory diseases, as an independent predictor of cardiac events. In this study, we aimed to evaluate the QRS duration and fQRS in patients with IBD. Methods: The presented study was designed as a single-center retrospective cohort study. The study population consisted of 217 patients with IBD and 195 healthy controls. QRS duration and presence of fQRS were evaluated using a 12-lead electrocardiogram. These parameters were compared between groups. Results: QRS duration was demonstrated to be higher in the IBD group compared to the control group (92 (86-98) vs. 82 (75-90), p<0.001). The presence of fQRS was significantly higher in the IBD group (n=101 (47%) vs n=59 (30%), p=0.006). In addition, a positive correlation was demonstrated between QRS duration and disease duration (Spearman's Rho= 0.4, p<0.001). Notably, disease and QRS duration were significantly higher in the fQRS (+) group (102 (56.5-154) vs. 55 (24.3-118.3), <0.001; 94 (86-100) vs. 92 (84-96), 0.016; respectively). Conclusion: Our results demonstrated that QRS prolongation and the presence of fQRS (+) were more common in IBD patients, and associated with longer disease duration. These findings may indicate subclinical cardiac involvement in IBD. Therefore, IBD patients, especially those with long-standing disease, should be followed more closely in terms of cardiac manifestations.

Clinical significance of R-wave amplitude in lead V1 and inferobasal myocardial infarction in patients with inferior wall myocardial infarction.

OBJECTIVE: To assess electrocardiogram (ECG) for risk stratification in inferior ST-elevation myocardial infarction (STEMI) patients within 24 h. METHODS: Three hundred thirty-four patients were divided into four ECG-based groups: Group A: R V1 <0.3 mV with ST-segment elevation (ST↑) V7-V9, Group B: R V1 <0.3 mV without ST↑ V7-V9, Group C: R V1 ≥0.3 mV with ST↑ V7-V9, and Group D: R V1 ≥0.3 mV without ST↑ V7-V9. RESULTS: Group A demonstrated the longest QRS duration, followed by Groups B, C, and D. ECG signs for right ventricle (RV) infarction were more common in Groups A and B (p < .01). ST elevation in V6, indicative of left ventricle (LV) lateral injury, was more higher in Group C than in Group A, while the ∑ST↑ V3R + V4R + V5R, representing RV infarction, showed the opposite trend (p < .05). The estimated LV infarct size from ECG was similar between Groups A and C, yet Group A had higher creatine kinase MB isoform (CK-MB; p < .05). Cardiac troponin I (cTNI) was higher in Groups A and C than in B and D (p < .05 and p = .16, respectively). NT-proBNP decreased across groups (p = .20), with the highest left ventricular ejection fraction (LVEF) observed in Group D (p < .05). Group A notably demonstrated more cardiac dysfunction within 4 h post-onset. CONCLUSIONS: For inferior STEMI patients, concurrent R V1 <0.3 mV with ST↑ V7-V9 suggests prolonged ventricular activation and notable myocardial damage. RV infarction's dominance over LV lateral injury might explain these observations.

Combined use of frontal plane QRS-T angle and platelet-to-lymphocyte ratio in the risk prediction of ischemic cardiomyopathy in STEMI.

BACKGROUND: Frontal plane QRS-T angle (fQRS-T) and platelet-to-lymphocyte ratio (PLR) are highly important parameters that well-predict unfavorable outcomes in patients with ST-elevated myocardial infarction (STEMI).There are limited data on the predictive significance of ischemic cardiomyopathy (I-CMP) from the combination of fQRS-T and PLR in STEMI, compared to using fQRS-T and PLR alone. AIM: We aimed to evaluate the ability of the combination of fQRS-T and PLR routinely obtained on admission to identify STEMI patients at risk of I-CMP. METHOD: Six hundred and thirty-eight consecutive patients with STEMI who underwent primary percutaneous coronary intervention between 2018 and 2021 were included. The assessment of I-CMP was conducted through two-dimentional (2D)-echocardiography 6 weeks post-STEMI and I-CMP was defined as a left ventricular ejection fraction (LVEF) of 50% or less. Multivariate logistic regression analysis and receiver operating curve (ROC) analysis were performed to predict the development of I-CMP. RESULTS: In ROC analysis, the cut-off values of fQRS-T and PLR for best predicting I-CMP were 66.72° and 101.23, respectively. The model using the combination of two markers was the most powerful predictor of I-CMP risk (OR: 3.183, 95% CI: 1.971-5.139, p = .001) when included in a single variable such as high fQRS-T or high PLR (OR: 1.422, 95% CI: 0.870-0.232, p = .160). Additionally, the concomitant presence of high fQRS-T and high PLR exhibited the highest specificity (77%) for I-CMP relative to the individual presence of high fQRS-T (66%) or PLR (49%). CONCLUSION: The combination of fQRS-T and PLR, which is a simple and cost-effective risk assessment, may serve as a more reliable prognosticator for I-CMP as opposed to the use of fQRS-T and PLR alone for STEMI.

Revisiting the diagnostic and prognostic significance of high-frequency QRS analysis in cardiovascular diseases: a comprehensive review.

Cardiovascular diseases (CVDs) present a significant global public health threat, contributing to a substantial number of cases involving morbidity and mortality. Therefore, the early and accurate detection of CVDs plays an indispensable role in enhancing patient outcomes. Decades of extensive research on electrocardiography at high frequencies have yielded a wealth of knowledge regarding alterations in the QRS complex during myocardial ischemia, as well as the methodologies to assess and quantify these changes. In recent years, the analysis of high-frequency QRS (HF-QRS) components has emerged as a promising non-invasive approach for diagnosing various cardiovascular conditions. Alterations in HF-QRS amplitude and morphology have demonstrated remarkable sensitivity as diagnostic indicators for myocardial ischemia, often surpassing measures of ST-T segment changes. This comprehensive review aims to provide an intricate overview of the current advancements, challenges, and prospects associated with HF-QRS analysis in the field of CVDs.

Electrocardiographic Z-axis QRS-T voltage-time-integral in patients with typical right bundle branch block - Correlation with echocardiographic right ventricular size and function.

BACKGROUND: Right bundle branch block (RBBB) can be benign or associated with right ventricular (RV) functional and structural abnormalities. Our aim was to evaluate QRS-T voltage-time-integral (VTI) compared to QRS duration and lead V1 R' as markers for RV abnormalities. METHODS: We included adults with an ECG demonstrating RBBB and echocardiogram obtained within 3 months of each other, between 2010 and 2020. VTIQRS and VTIQRST were obtained for 12 standard ECG leads, reconstructed vectorcardiographic X, Y, Z leads and root-mean-squared (3D) ECG. Age, sex and BSA-adjusted linear regressions were used to assess associations of QRS duration, amplitudes, VTIs and lead V1 R' duration/VTI with echocardiographic tricuspid annular plane systolic excursion (TAPSE), RV tissue Doppler imaging S', basal and mid diameter, and systolic pressure (RVSP). RESULTS: Among 782 patients (33% women, age 71 ± 14 years) with RBBB, R' duration in lead V1 was modestly associated with RV S', RV diameters and RVSP (all p ≤ 0.03). QRS duration was more strongly associated with RV diameters (both p < 0.0001). AmplitudeQRS-Z was modestly correlated with all 5 RV echocardiographic variables (all p ≤ 0.02). VTIR'-V1 was more strongly associated with TAPSE, RV S' and RVSP (all p ≤ 0.0003). VTIQRS-Z and VTIQRST-Z were among the strongest correlates of the 5 RV variables (all p < 0.0001). VTIQRST-Z.√BSA cutoff of ≥62 µVsm had sensitivity 62.7% and specificity 65.7% for predicting ≥3 of 5 abnormal RV variables (AUC 0.66; men 0.71, women 0.60). CONCLUSION: In patients with RBBB, VTIQRST-Z is a stronger predictor of RV dysfunction and adverse remodeling than QRS duration and lead V1 R'.

Case of a misleading ECG.

An elderly man with severe chronic obstructive pulmonary disease and a history of complete heart block with pacemaker placement was found to have pacemaker lead infection and required device extraction. He had a standard dual chamber pacemaker in place, however the ECG obtained showed paced QRS complexes with presence of R wave in lead V1 and QS in lead I suggestive of left ventricular pacing. Additional imaging with CT scan obtained for confirmation revealed that the heart was displaced to the left posterior hemithorax secondary to pulmonary disease. Due to significant posterolateral rotation of the heart, a right ventricular paced rhythm can demonstrate Q/S waves in the lateral leads (I, aVL, V5-6) and R waves in the right precordial leads (V1-3). This can be misdiagnosed as a left ventricular paced rhythm.

Relationship between fragmented QRS complex and early left ventricular dysfunction after mitral valve repair.

BACKGROUND: Preoperative left ventricular (LV) ejection fraction (PreLVEF) and preoperative LV end-systolic diameter (PreESD) are known predictors for postoperative LV dysfunction after mitral valve repair (MVR). Fragmented QRS (fQRS) evaluated in 12-derivation electrocardiography has widely been accepted as a sign of myocardial fibrosis. In the present study, we aimed to evaluate the relationship between fQRS in preoperative 12­lead electrocardiography (ECG) and postoperative LV dysfunction that develop after MVR in patients with severe primary mitral regurgitation (MR) due to mitral valve prolapse (MVP). METHODS: From 2019 to 2022, 49 patients who had undergone successful MVR surgery for severeMR caused by MVP were enrolled in the study. The preoperative and postoperative echocardiographic data were collected retrospectively. We analyzed the demographic, echocardiographic, operative and postoperative parameters to assess the relationship between fQRS and early postoperative LV dysfunction, defined as an LVEF<60%. RESULTS: PreLVEF of all patients were ≥ %65. A total of 22 patients had fQRS (44.9%) and postoperative LV dysfunction was found to be 36.7%. A significantly higher rate of fQRS was observed in the group with postoperative LV dysfunction compared to the group without (12 (66.7%) vs 10 (32.3%), p: 0.036). In multivariate analysis for fQRS, PreESD, preoperative pulmonary artery systolic pressure (PrePASP), preoperative atrial fibrillation (PreAF), and male gender, only fQRS was found to be a significant predictor of postoperative LV dysfunction (p: 0.003, OR: 4.28, 95% CI (1.15-15.96). CONCLUSION: fQRS was found to be a predictor of postoperative LV dysfunction in the early period after MVR. fQRS may be a readily available and cost-effective test that can be used in clinical practice to predict postoperative LV dysfunction in patients undergoing MVR.

Pseudo precordial ST-segment depression.

We present a case with acute coronary syndrome and very unusual QRS widening in the acute phase. The case highlights that non-specific intraventricular conduction delay should be considered as a high risk ECG pattern predicting poor prognosis.

Different degrees of anterior displacement of QRS complex.

Electrocardiogram of a patient affected by hypertrophic cardiomyopathy showed normal PR and QRS intervals and signs of left ventricular hypertrophy. In leads I,V5 and V6 the initial q waves were absent. A subsequent electrocardiogram revealed the appearance of prominent anterior QRS forces expressed by a change from rS to R pattern in leads V2 and V3 with a tall R wave in V2. PR and QRS intervals and QRS axis remained substantially unchanged. Other electrocardiograms showed day-to-day variations of the anterior displacement of QRS complex. The different degrees of anterior displacement appear to be an expression of an underlying left septal fascicular block, but a diagnosis cannot be made with certainty.