Incomplete Right Bundle Branch Block Research Articles

A 20–YEAR FOLLOW–UP OF SUCCESSFUL SURGICAL MANAGEMENT OF DOUBLE–OUTLET RIGHT VENTRICLE WITH PULMONARY STENOSIS: A CASE REPORT

Abstract A 25–year–old man, suffering from worsening exertional dyspnea for 4 months, was referred to our Cardiology Unit. The patient was previously diagnosed with a late diagnosis of double outlet right ventricle (DORV), as well as pulmonary stenosis, VSD, and right–sided aortic arch for which he underwent a first surgical procedure around the age of 2 involving an intersternal anastomosis through a left lateral thoracotomy approach. A second intervention took place 2 years later for a radical correction of the anomaly through a median sternotomy. The patient had sporadic follow–up since then. A baseline ECG was performed, showing evidence of sinus rhythm, normal AV with a bifid P wave in lead II, slight RAD, incomplete RBBB, and asymmetric negative T waves from V1 to V3 and in aVL, and biphasic T waves in V4–V5. We performed an echocardiogram which showed: a dilated RA, a normal–sized LA, an apparently intact interatrial septum without evident shunts; a normal sized LV; EF 60%; a moderately dilated, hypertrophic and hypertrabeculated RV; FAC 33%; normal aortic flow; a minimal MR; a massive residual pulmonary insufficiency; a moderate TR; a dilatated pulmonary trunk; a normal–sized and collapsible IVC upon inspiration; PAPs of 70 mmHg; no pericardial effusion. A maximal exercise stress test appeared to be normal throughout. However, due to the severe pulmonary hypertension he was referred to our PH centre. While these patients are commonly affected by residual early or late left ventricular outflow tract obstruction, fortunately our patient was not. DORV is a relatively common congenital heart defect characterized by an abnormal connection between the ventricles and arteries, in which both the aorta and the pulmonary trunk are connected completely or predominantly to the right ventricle. The anatomical spectrum of this anomaly is quite large, and it can be associated with the presence of a VSD that often extends towards one or both of the arterial valves, allowing the flow of blood from the left ventricle to the aorta. An accurate diagnosis through echocardiography or CMR is essential in order to guide the surgical repair and the appropriate therapeutic approach for individuals affected by this anomaly. A successful surgical correction of DORV is essential, but it is important to be aware of the potential complications of post–operative PH (especially in patients with preoperative PH), which necessitates close surveillance and appropriate therapeutic management.

A CASE OF PULMONARY HYPERTENSION ASSOCIATED WITH MYELOFIBROSIS: THERAPEUTICAL CHALLENGES FROM ACUTE TO CHRONIC SETTING

Abstract A 85–year–old female was transferred to our ICCU for acute heart failure from one of our spoke hospitals. The patient had a long history of chronic myelofibrosis, treated with fedratinib as a second–line agent after ruxolitinib failure. During a recent hospital admission, transthoracic echocardiography already showed signs of severe pulmonary hypertension (PH) with right ventricular (RV) dysfunction, so diuretic was started. On admission the patient presented showed consistent with acute on chronic kidney injury (serum Cr 3.2 mg/dl), stable anemia (Hb 9.2 mg/dl) and markedly elevated Nt–proBNP. A pulmonary CT–scan excluded acute pulmonary embolism and lung parenchymal alterations, with a clear dilation of main pulmonary artery. Transthoracic echocardiography (figure 1) confirmed precapillary PH phenotype diagnosis. Electrocardiogram (figure 2) showed sinus rhythm; incomplete RBBB, T wave inversion in V2 to V4. The patient was initially treated with high dose furosemide, low flow oxygen; but later she needed multiple cycles of inotropes, vasopressors and combined diuretic therapy (metolazone and acetazolamide) to stabilize the clinical setting. The patient also experienced episodes of paroxysmal high ventricular rate atrial flutter. After resolution of volume overload, a right heart catheterization was performed and findings were consistent with severe precapillary pulmonary hypertension: PA pressure 90/58/40 mmHg, normal PCWP, high PVR, mild cardiac index reduction. Due to critical clinical situation, Sildenafil 20 mg was started as an off–label therapy for PH (group 5). Subsequently, the patient experienced gradual but constant hemodynamic and clinical improvement and was discharged in NYHA class II. At 1 month control, patient was stable, echocardiogram revealed improvement in right ventricle dimension, systolic function and right atrial enlargement. At three months, patient is still in an intermediate risk class for PH, so we are evaluating a combination therapy (either endothelin receptor antagonist or prostanoids), taking into account anemia and thrombocytopenia. Take home message: PH can be a complication of hematological disorders as myelofibrosis, included in “mixed” forms (group 5) of PH. In our patient, after a challenging management for acute right heart failure, an off–label PDE–5 inhibitor stabilized the clinical scenario: more data are needed on PH drugs use in this setting where up to now therapeutic strategies are lacking.

Electrical and structural remodelling in female athlete's heart: A comparative study in women vs men athletes and controls

BackgroundAthlete's heart is associated with physiological electrical and structural remodelling. Despite the plethora of data published on male athletes, solid data derived from female athletes, compared to male counterparts or sedentary women, are still scarce. ObjectivesWe aimed to analyze the electrical, structural, and functional characteristics of athlete's heart in female and male athletes vs sedentary controls. MethodsOlympic athletes and sedentary controls were evaluated by resting ECG and echocardiography. Athletes were divided into 4 different sports groups. ResultsThe study population included 1096 individuals (360 female athletes, 410 male athletes, 130 sedentary women and 196 sedentary men). Female athletes had lower resting heart rate, longer PR interval, higher voltage of R, and T waves and more frequently incomplete RBBB, left ventricular (LV) hypertrophy, early repolarization, and anterior T-wave inversion as compared to controls.Biventricular cavity dimensions and LV wall thickness were greater in female athletes than in female controls. However, women showed a lower degree of training-induced structural remodelling than men. In female athletes, both cavity dimensions and LV wall thickness increased from those engaged in skill and power to mixed and endurance disciplines. However, in female athletes, contrary to males, the ECG changes were not significantly different according to the different types of sport discipline. ConclusionsHighly-trained women demonstrate relevant training-induced electrical and structural remodelling. However, the type of sport did not influence ECG parameters in women, contrary to men, while it impacted biventricular morphologic remodelling, with endurance athletes showing the greatest degree of adaptation.

Electrocardiographic evolution in Anderson-Fabry disease: a valuable tool to detect progressive cardiac involvement

Abstract Background Anderson-Fabry disease (AFD) is a multisystemic disorder caused by accumulation of glycosphingolipid in affected tissues and cardiac involvement can manifest with left ventricular hypertrophy (LVH), conduction delays, arrythmias and valvulopathies. Electrocardiogram (ECG) has proven to be useful for early detection of this condition, but there are only few datas on the association between ECG alterations and the progression of the disease. Purpose To evaluate the association between ECG anomalies and progressive cardiac involvement in AFD patients with different degrees of left ventricular hypertrophy. Methods We recruited 189 AFD patients > 18 years old (39% males, median age 47 years, 68% classical AFD) in a multicentre cohort and we divided them into 4 groups according to different degree of left ventricular (LV) thickness: group A ≤ 9mm (n = 52, 28%); group B 10-14 mm (n = 76, 40%); group C 15-19 mm (n = 46, 24%); group D ≥ 20 mm (n = 15, 8%). They underwent a complete clinical, ECG and echocardiographic evaluation and we analysed their ECG features in order to detect patterns suggestive of the different stages of AFD. Results A normal ECG was present in 87% of patients in group A, 54% in group B, 11% in group C, and 7% in group D. The most common conduction delay type was right bundle branch block (RBBB), mainly incomplete in groups B and C (respectively 20% and 22%) and complete RBBB in group D (53%), with p < 0.001; whereas none of the patients had LBBB. The prevalence of LVH criteria showed a statistically significant increase among the groups (p < 0.001) and also negative T waves and ST segment depression were more frequent in group C and D (p < 0.001), involving mainly lateral and inferior leads. Analysing these results we proposed ECG patterns representative of different AFD stages characterized by increasing LV thickness. In patients with normal LV thickness (group A) we noticed a high prevalence of normal ECG (87%) and minor anomalies like LVH criteria/giant positive T waves (8%) and delta wave/slurred QRS onset together with borderline PR (8%). Differently patients with intermediate LV thickness (group B and C) show more heterogeneous ECG alterations: LVH/giant positive T waves (17% and 7%); LVH+LV strain (9% and 17%); incomplete RBBB associated with repolarization abnormalities (8% and 9%) which were more frequently associated with LVH criteria in group C than B (8% and 15% respectively). In patients with severe LVH (group D) we detected more significant anomalies, like complete RBBB associated to LVH and repolarization abnormalities (40%), sometimes with QRS fragmentation (13%). Conclusions ECG represents an important tool for early detection and long-term monitoring of cardiac involvement in AFD with particular ECG features that evolve together with the natural history of the disease and with the progression of the LVH. Their potential association with clinical events remains unknown.

Electrocardiogram analysis in Anderson-Fabry disease: a valuable tool for progressive phenotypic expression tracking.

Electrocardiogram (ECG) has proven to be useful for early detection of cardiac involvement in Anderson-Fabry disease (AFD); however, little evidence is available on the association between ECG alterations and the progression of the disease. To perform a cross sectional comparison of ECG abnormalities throughout different left ventricular hypertrophy (LVH) severity subgroups, providing ECG patterns specific of the progressive AFD stages. 189 AFD patients from a multicenter cohort underwent comprehensive ECG analysis, echocardiography, and clinical evaluation. The study cohort (39% males, median age 47 years, 68% classical AFD) was divided into 4 groups according to different degree of left ventricular (LV) thickness: group A ≤ 9 mm (n = 52, 28%); group B 10-14 mm (n = 76, 40%); group C 15-19 mm (n = 46, 24%); group D ≥ 20 mm (n = 15, 8%). The most frequent conduction delay was right bundle branch block (RBBB), incomplete in groups B and C (20%,22%) and complete RBBB in group D (54%, p < 0.001); none of the patients had left bundle branch block (LBBB). Left anterior fascicular block, LVH criteria, negative T waves, ST depression were more common in the advanced stages of the disease (p < 0.001). Summarizing our results, we suggested ECG patterns representative of the different AFD stages as assessed by the increases in LV thickness over time (Central Figure). Patients from group A showed mostly a normal ECG (77%) or minor anomalies like LVH criteria (8%) and delta wave/slurred QR onset + borderline PR (8%). Differently, patients from groups B and C exhibited more heterogeneous ECG patterns: LVH (17%; 7% respectively); LVH + LV strain (9%; 17%); incomplete RBBB + repolarization abnormalities (8%; 9%), more frequently associated with LVH criteria in group C than B (8%; 15%). Finally, patients from group D showed very peculiar ECG patterns, represented by complete RBBB + LVH and repolarization abnormalities (40%), sometimes associated with QRS fragmentation (13%). ECG is a sensitive tool for early identification and long-term monitoring of cardiac involvement in patients with AFD, providing "instantaneous pictures" along the natural history of AFD. Whether ECG changes may be associated with clinical events remains to be determined.

The impact of right bundle branch block and SIQIII-type patterns in determining risk levels in acute pulmonary embolism.

Background: Electrocardiography (ECG) findings in acute pulmonary embolism (PE) are known to be related to various right ventricular (RV) alterations. These abnormalities are not included in risk stratification algorithms despite emerging evidence of their association with patient outcomes. We aimed to analyze the impact of right bundle branch block (RBBB) and/or SIQIII patterns as indicators for determining the level of risk in patients with PE. Methods: We performed a retrospective cohort study including all patients with confirmed acute PE hospitalized from January 2008 to December 2019 in two tertiary care cardiology departments. The first ECG taken at admission was selected and the analysis focused on the presence of a complete or an incomplete RBBB and SIQIII-type patterns. Results: A total of 255 patients were divided into two groups: Group I (47.8%, n=122) included patients with PE without RBBB nor SIQIII patterns, and Group II (52.2%, n=133) included patients with RBBB and/or SIQIII patterns. Patients in group II presented significantly more frequently with acute right heart symptoms (45.1% vs. 18%, p<0.001) and cardiogenic shock at admission (31.6 vs. 4.1%, p<0.001). Echocardiographic parameters indicating right heart injury also occurred more significantly in group II patients (p<0.001). By univariate analysis, patients in group II were found to be significantly associated with in-hospital mortality (22.6 vs. 6.1%, p=0.002) and major cardiovascular events (MACEs) during hospitalization (43.3 vs. 13.7%, p<0.001). Multivariate logistic regression analysis identified five independent factors predictive of MACEs: SIQIII and/or RBBB, renal failure, positive troponin levels, RV dysfunction and right heart failure symptoms during initial presentation. Kaplan-Meier survival analysis identified the inclusion in Group II and the presence of SIQIII pattern as predictors of overall mortality (p<0.001). Conclusions: Our study suggests an important and independent prognostic value of RBBB and SIQIII patterns and their usefulness in determining the outcome of PE patients.

Electrical and structural remodelling in female athlete's heart: a study in women practising competitive sports

Abstract Funding Acknowledgements Type of funding sources: None. Background Athlete’s heart is associated with a physiological electrical and structural remodelling induced by training. While several data have been published in male athletes, data on female competitive athletes, and their comparison with male counterparts or sedentary women, are still inconclusive. Objectives This study aimed to analyze the electrical, structural, and functional cardiac remodelling in female and male competitive athletes and sedentary controls. Methods Competitive athletes were evaluated by 12-lead resting ECG and echocardiography and compared to the sedentary controls. Results The study population was composed of 1,096 individuals (360 female Olympic athletes, 410 male Olympic athletes, 130 sedentary women and 196 sedentary men). Female athletes had lower resting heart rate, longer PR interval, higher voltage of P, R, and T waves and more frequently incomplete RBBB, left ventricular (LV) hypertrophy, early repolarization, and anterior T-wave inversion as compared with non-athletes. Biventricular dimensions and LV wall thickness were greater in female athletes as compared to non-athletes. However, women showed a lower degree of training-induced structural remodelling than men. A progressive increase in biventricular dimensions and LV wall thickness was observed from athletes engaged in skill and power to those practicing mixed and endurance disciplines. However, in women, but not in men, the type of sport did not significantly influence ECG remodelling. Conclusions Highly-trained women demonstrate a relevant training-induced electrical and structural remodelling. However, the type of sport did not influence ECG parameters in women while it impacted on biventricular remodelling, with female endurance athletes showing the greatest degree of adaptation.

486 ELECTROCARDIOGRAPHIC EVOLUTION IN ANDERSON-FABRY PATIENTS ON DISEASE SPECIFIC THERAPY

Abstract Background Anderson-Fabry disease (AFD) is an X-linked lysosomal storage disorder that have gained attention due to the availability of therapeutic options. Disease specific therapy (DST), either by enzyme replacement therapy or oral pharmacological chaperone, is the mainstay for AFD treatment. Although its widespread use, few data are available on the electrocardiographic variations associated with DST. Purpose To evaluate ECG findings and variations in AFD according to time duration of DST, comparing patients under long-term therapy with naïve patients starting therapy during follow-up. Methods One-hundred-seventy-nine AFD patients, ≥18 years old, with 2 readable ECGs, were recruited in the present multicentre study cohort. Two patients were excluded due to pacemaker (PM) implantation. Only patients on DST (n=107) were considered for final cohort and divided into 2 groups according to therapy duration: Group A (n=42) included patients treated for ≥12 months at the time of first evaluation, whereas Group B patients (n=65) started therapy during follow-up. Results Group A and Group B had not significant difference in terms of age at presentation (48[39-60] vs 48[36-56]years; p=0.856) and maximal wall thickness (13[11-15] vs 13[11-18]mm; p=0.090) whereas they differed for male prevalence (61% vs 38%; p=0.029) and classic phenotype (86% vs 29%; p&amp;lt;0.0001). At baseline, more than half of both groups had ECG abnormalities (61% vs 61%; p=1.000). The prevalence among Group A and Group B of atrial fibrillation (AF 5% vs 6%; p=1.000), first degree atrioventricular block (AVB, 7% vs 5%; p=0.677), right bundle branch block (RBBB, complete 7% vs 8%; p=1.000; incomplete RBBB 14% vs 12%; p=0.776), left anterior fascicular block (LAFB, 10% vs 9%;p=1.000) and repolarization abnormalities (48% vs 38%; p=0.423) was not significantly different. Conversely, left ventricular hypertrophy (LVH) was more prevalent in Group A (64% vs 37%; p=0.010). During the follow-up (57[60-28] months for Group A vs 70[37-85] months for Group B; p=0.152), both groups developed electrocardiographic alterations (38% vs 23%; p=0.127). Specifically, in GroupA, 4 (10%) patients presented AF, 1 (2%) AVB, 7 (17%) complete or incomplete RBBB, 4 (10%) LAFB, 1 (2%) LVH and 8 (19%) repolarization abnormalities. In Group B, 2 (3%) developed AF, 1 (2%) AVB, 7 (11%) complete or incomplete RBBB, 2(3%) LVH and 11(17%) repolarization abnormalities; none developed LAFB. Conclusions In this AFD cohort, both patients on chronic DST (Group A) and patients who started treatment during follow-up (Group B) developed ECG alterations. Treatment status didn't affect considerably the developing of ECG abnormalities and DST did not prevent ECG changes. ECG alterations during the follow-up were more frequent in Group A (38% vs 23%), mainly composed by classic phenotype and male patients, thus supporting a prompt start of therapy at an early stage.

1141 CARDIAC METASTASIS

Abstract Introduction: in medical literature, studies on cardiac metastases are few and discordant and their actual incidence is underestimated. Autoptic examination shows evidence of cardiac metastases in about 9% of all the patients affected by malignant tumor. Each malignant tumor can metastasize to the heart (incidence varying from 2.3% to 18.3%); nevertheless, formation of cardiac metastases is more frequently associated with primitive neoplasms such as pleural mesothelioma (48.4%), melanoma (27.8%), adenocarcinoma as well as lung and kidney carcinomas. Clinical case: patient aged 66, former smoker, no further cardiovascular disease risk factors, no occurrences of heart disease in his past medical history. In 2008 surgical excision of melanoma skin cancer, negative sentinel lymph node. In 2014 cancer relapse, final cycle of chemotherapy treatment completed in July. In October 2014 evidence of liver and adrenal gland metastases. In November 2014 evidence of bone metastases. As the CT scan showed evidence of pleural and pericardial effusion, the patient was requested to undergo cardiac examination and an echocardiogram test in preparation for further chemotherapy treatment. During the medical examination the patient presented with symptoms of marked asthenia, dyspnea under moderate effort (NYHA II), palpitations. BP: 100/60 mmHg. ECG: low voltages, sinus tachycardia, incomplete RBBB, inverted T waves in V1 – V4, III. Home Therapy: Furosemide 25 mg, Cortisone 25 mg, Tramadolo Cloridrato 50 mg, Albumina. The findings of the echocardiogram test showed: enlarged and hyperkinetic left ventricle, abundant circumferential pericardial effusion measuring up to 2,3 cm. Evidence of hyperechogenic areas in the epicardium, myocardium and at the level of mitral valve flaps (figure 1 and 2). In December 2014 hospital admission due to worsening of clinical symptoms, onset of ascites, hyperpotassemia, anemization (Hb 8.6g/dL). During the 72 hours following hospitalisation: STEMI, acute kidney failure, respiratory failure, metabolic acidosis, death. The autoptic examination showed evidence of undifferentiated large cell neoplasm with formation of metastases in the myocardium, mitral valve apparatus and coronary tree. Conclusions echocardiography should always be included in the clinical examinations which patients affected by neoplasm are required to undergo. Serial evaluations allow to identify the occurrence of pericardial effusion and/or heart involvement even in the absence of clinical suspicion. Identifying such anomalies may have important therapeutic implications.

Electrocardiographic findings in Anderson-Fabry patients on disease specific therapy: can treatment prevent ECG changes?

Abstract Background Anderson-Fabry disease (AFD) is an X-linked lysosomal storage disorder that have gained attention due to the availability of therapeutic options. Disease specific therapy (DST), either by enzyme replacement therapy or oral pharmacological chaperone, is the mainstay for AFD treatment. Although its widespread use, few data are available on the electrocardiographic variations associated with DST. Purpose To evaluate ECG findings and variations in AFD according to time duration of DST, comparing patients under long-term therapy with naïve patients starting therapy during follow-up. Methods One-hundred-seventy-nine AFD patients, ≥18 years old, with 2 readable ECGs, were recruited in the present multicentre study cohort. Two patients were excluded due to pacemaker (PM) implantation. Only patients on DST (n=107) were considered for final cohort and divided into 2 groups according to therapy duration: Group A (n=42) included patients treated for ≥12 months at the time of first evaluation, whereas Group B patients (n=65) started therapy during follow-up. Results Group A and Group B had no significant difference in terms of age at presentation (48 [39–60] vs 48 [36–56] years; p=0.856) and maximal wall thickness (13 [11–15] vs 13 [11–18] mm; p=0.090) whereas they differed for male prevalence (61% vs 38%; p=0.029) and classic phenotype (86% vs 29%; p&amp;lt;0.0001). At baseline, more than half of both groups had ECG abnormalities (61% vs 61%; p=1.000). The prevalence among Group A and Group B of atrial fibrillation (AF, 5% vs 6%; p=1.000), first degree atrioventricular block (AVB, 7% vs 5%; p=0.677), right bundle branch block (RBBB, complete 7% vs 8%; p=1.000; incomplete RBBB 14% vs 12%; p=0.776), left anterior fascicular block (LAFB, 10% vs 9%; p=1.000) and repolarization abnormalities (48% vs 38%; p=0.423) was not significantly different. Conversely, left ventricular hypertrophy (LVH) was more prevalent in Group A (64% vs 37%; p=0.010). During the follow-up period (57 [60–28] months for Group A vs 70 (37–85) months for Group B; p=0.152), both groups developed electrocardiographic alterations (38% vs 23%; p=0.127). In particular, in Group A, 4 (10%) patients presented AF, 1 (2%) AVB, 7 (17%) complete or incomplete RBBB, 4 (10%) LAFB, 1 (2%) LVH and 8 (19%) repolarization abnormalities. In Group B, 2 (3%) developed AF, 1 (2%) AVB, 7 (11%) complete or incomplete RBBB, 2 (3%) LVH and 11 (17%) repolarization abnormalities; none developed LAFB. Conclusions In this AFD cohort, both patients on chronic DST (Group A) and patients who started treatment during follow-up (Group B) developed ECG alterations. ECG changes during the follow-up were more frequent in Group A (38% vs 23%), mainly composed by classic phenotype and male patients, suggesting a prompt start of therapy at an early stage. Funding Acknowledgement Type of funding sources: None.

MORPHOLOGIC CHARACTERISTICS AND FUNCTION OF RIGHT VENTRICLE IN PATIENTS WITH ISOLATED RIGHT BUNDLE BRANCH BLOCK

Background: The prevalence of right bundle branch block (RBBB) is estimated in 0.2 to 1.3% of healthy people. RBBB had independent association with decreased right ventricle (RV) function, which is considered as predictor of adverse cardiovascular outcomes. The aim of this study is to evaluate RV structure and function in patients with isolated RBBB (without structural heart disease) using two-dimensional echocardiography. Methods: A cross-sectional study conducted at Chitwan Medical College, Bharatpur from 1st January 2022 to 30th June 2022. Consecutive adult patients aged ≥18 years with isolated RBBB classified into complete RBBB (CRBBB) and Incomplete RBBB (IRBBB) based on electrocardiographic findings. The echocardiographic evaluation was done to assess RV dimension and function. Results: A total of 52 patients with isolated RBBB were included with mean age of the study population was 45.3 ± 9.3 years, (28 ,53.8%) had CRBBB, whereas the remaining (24, 46.2%) had IRBBB. Among the parameters used to assess RV function; mean RV-Fractional area change (P&lt;0.001), Tricuspid annular plane systolic excursion(P&lt;0.02) and Pulsed Doppler peak velocity at the lateral annulus RV(P&lt;0.001) were significantly lower, while Pulsed Doppler myocardial performance index(P&lt;0.001) was significantly high in CRBBB group as compared to IRBBB group. Similarly, Right atrium and RV dimensional parameters were significant higher in CRBBB compared to IRBBB group. Conclusions: Isolated RBBB is not as benign as it was considered and has deteriorating effect on RV morphology and function. Therefore, patients with Isolated RBBB need follow-up with passing age and more attention toward RV structural and functional analysis.

Prevalence and incidence of intraventricular conduction disturbances among Chinese adults: Results from the Kailuan study.

ObjectivesEpidemiological data on intraventricular conduction disturbances (IVCDs) are limited in the Chinese population. We aimed to investigate the prevalence and incidence of different types of IVCDs among Chinese adults.MethodsFrom June 2006 to October 2007, a total of 100,250 individuals from the Kailuan Study underwent electrocardiogram examinations. Follow-up visits were performed biennially. The prevalence and incidence of right bundle branch block (RBBB), incomplete RBBB (IRBBB), left bundle branch block (LBBB), incomplete LBBB, left anterior fascicular block (LAFB), left posterior fascicular block (LPFB) and non-specific IVCD (NIVCD) were calculated. Their association with risk factors and cardiovascular diseases was also investigated.ResultsThe prevalence and incidence of all IVCDs were 3.19 and 1.70%, respectively. RBBB, IRBBB, and LAFB were the IVCD types that had the highest prevalence and incidence. The prevalence (3.67% vs. 1.29%; P < 0.001) and incidence (1.93% vs. 0.84%; P < 0.001) of IVCDs were higher among males than among females. The prevalence and incidence of most IVCD types increased with age. IRBBB, LBBB, and LAFB were significantly associated with hypertension. LBBB and NIVCD were associated with diabetes mellitus. In addition, LBBB and LAFB were related to prior myocardial infarction.ConclusionIVCDs differ in prevalence and incidence according to sex and age group. They also show disparate associations with other cardiovascular comorbidities. These differences need to be considered in daily clinical practice.

Defining electrocardiographic criteria to differentiate non-type 1 Brugada ECG variants from normal incomplete RBBB patterns in the young SCD-SOS cohort.

We assessed the prevalence of non-type 1 Brugada pattern (T1BrP) in children and young adults from the Sudden Cardiac Death-Screening Of risk factorS cohort and the diagnostic yield of nonexpert manual and automatic algorithm electrocardiogram (ECG) measurements. Cross-sectional study. We reviewed 14 662 ECGs and identified 2226 with a rSr'-pattern in V1-V2. Among these, 115 were classified by experts in hereditary arrhythmic-syndromes as having or not non-T1BrP, and were compared with measurements of 5 ECG-derived parameters based on a triangle formed by r' -wave (d(A), d(B), d(B)/h, β-angle) and ST-ascent, assessed both automatically and manually by nonexperts. We estimated intra- and interobserver concordance for each criterion, calculated diagnostic accuracy and defined the most appropriate cut-off values. A rSr'-pattern in V1-V2 was associated with higher PQ interval and QRS duration, male gender, and lower body mass index (BMI). The manual measurements of non-T1BrP criteria were moderately reproducible with high intraobserver and moderate interobserver concordance coefficients (ICC: 0.72-0.98, and 0.63-0.76). Criteria with higher discriminatory capacity were: distance d(B) (0.72; 95% confidence interval [CI]: 0.65-0.80) and ST-ascent (0.87; 95% CI: 0.82-0.92), which was superior to the 4 r'-wave criteria together (area under curve [AUC: 0.74]). We suggest new cut-offs with improved combination of sensitivity and specificity: d(B) ≥ 1.4 mm and ST-ascent ≥ 0.7 mm (sensitivity: 1%-82%; specificity: 71%-84%), that can be automatically measured to allow classification in four morphologies with increasing non-T1BrP probability. rSr'-pattern in precordial leads V1-V2 is a frequent finding and the detection of non-T1BrP by using the aforementioned five measurements is reproducible and accurate. In this study, we describe new cut-off values that may help untrained clinicians to identify young individuals who may require further work-up for a potential Brugada Syndrome diagnosis.

An Electrocardiographic Characterization of Left Bundle Branch Area Pacing-Induced Right Ventricular Activation Delay: A Comparison With Native Right Bundle Branch Block.

BackgroundLeft bundle branch area pacing (LBBAP) induces delayed RV activation and is thought to be harmless, since the electrocardiographic signature is reminiscent to native RBBB. However, to what extent the delayed RV activation during LBBAP truly resembles that of native RBBB remains unexplored.MethodsThis study included patients with incomplete RBBB (iRBBB), complete RBBB (cRBBB) and patients who underwent LBBAP. Global and right ventricular activation times were estimated by QRS duration and R wave peak time in lead V1 (V1RWPT) respectively. Delayed RV activation was further characterized by duration, amplitude and area of the terminal R wave in V1.ResultsIn patients with LBBAP (n = 86), QRS duration [120 ms (116, 132)] was longer compared to iRBBB patients (n = 422): 104 ms (98, 110), p < 0.001, but shorter compared to cRBBB (n = 223): 138 ms (130, 152), p < 0.001. V1RWPT during LBBAP [84 ms (72, 92)] was longer compared to iRBBB [74 ms (68, 80), p < 0.001], but shorter than cRBBB [96 ms (86, 108), p < 0.001]. LBBAP resulted in V1 R′ durations [42 ms (28, 55)] comparable to iRBBB [42 ms (35, 49), p = 0.49] but shorter than in cRBBB [81 ms (68, 91), p < 0.001]. During LBBAP, the amplitude and area of the V1 R′ wave were more comparable with iRBBB than cRBBB. V1RWPT during LBBAP was determined by baseline conduction disease, but not by LBBAP capture type.ConclusionLBBAP-induced delayed RV activation electrocardiographically most closely mirrors the delayed RV activation as seen with incomplete rather than complete RBBB.

Electrocardiographic analysis of left bundle branch area pacing induced right ventricular activation delay

Abstract Funding Acknowledgements Type of funding sources: None. Background Left bundle branch area pacing (LBBAP) aims to capture the area of left bundle branch, resulting in fast activation of the left ventricle (LV) but delayed right ventricular (RV) activation. During intrinsic cardiac conduction, delayed RV activation results on the electrocardiogram (ECG) in a right bundle branch block (RBBB) pattern and is generally considered benign. As such, LBBAP-induced delayed RV activation is thought not to be harmful. However, to what extent left and right ventricular activation times during LBBAP resembles that of healthy individuals with acquired RBBB is currently not known. Methods Individuals with incomplete RBBB (iRBBB), complete RBBB (cRBBB) and LBBAP were included. Standard twelve lead electrocardiograms (ECG) were stored and analysed digitally using the MUSE ECG database. QRS duration was measured as global QRS duration. Left and right ventricular activation times were estimated by R-wave peak time in lead V6 (V6RWPT) and R’ peak time in lead V1 (V1RWPT), respectively. Delayed RV activation was further characterized by duration and area of R’ wave in lead V1. Results Paced QRS duration during LBBAP (n=86) measured 129±15ms whereas QRS duration of iRBBB (n=422) and cRBBB (n=223) individuals measured 103±8ms and 142±17ms respectively (p&amp;lt;0.001). V6RWPT during LBBAP (47±15ms) was significantly longer than V6RWPT in iRBBB (40±5ms) and cRBBB (39±7ms) (p&amp;lt;0.001). With LBBAP, V1RWPT (83±15ms) became delayed compared to iRBBB (74±9ms, p&amp;lt; 0.001), but remained shorter in comparison to cRBBB (98±17ms, p&amp;lt;0.001). Patients with LBBAP were further characterized by V1 R’ duration and R’ area which were shorter and smaller compared to cRBBB but similar to iRBBB individuals. Conclusion LBBAP-induced delayed RV activation resembles electrocardiographically more closely to the delayed RV activation as seen in individuals with incomplete rather than complete RBBB. Left ventricular activation times remain slightly prolonged during LBBAP as compared to RBBB individuals.

Electrocardiographic Patterns of Atrial Septal Defects

Objective: This study was designed to evaluate the electrocardiographic features of Atrial Septal Defect to establish an association with crochetage pattern and incomplete RBBB. Materials and methods: ASDs of Primum, Secundum and Sinus Venosus type were included in this study. From October 15, 2003 till January 15, 2004, a total of 104 consecutive patients of ASD were studied at Punjab Institute of Cardiology, Lahore. Patients were included in the study after confirmation of Atrial Septal Defect on transesophageal echocardiography. Results: The mean age of the study population was 26.28±11.40 years. Among these 56(53.8%) patients were females and 48(46.2%) patients were males. The study population consisted of 94(90.4%) Secundum ASD patients followed by Sinus Venosus ASD 8(7.7%) patients and Primum ASD in only 2(1.9%) patients. Only 59(56.7%) patients had crochetage pattern in any of the leads while it was absent in 45(43.3%) patients p=0.470. Incomplete RBBB was present in 92(88.4%) patients. It was observed in 2(1.9%) patients in ASD Primum, 82(78.8%) patients in ASD Secundum and 8(7.7%) patients in ASD Sinus Venosus type. P=0.483.Conclusion: Although we did not observe a statistically significant association between crochetage pattern or incomplete RBBB and ASD but the presence of any of these two considerably increases the specificity of the ECG for the diagnosis of ASD.

Abstract 13986: De Novo Occurrence Of Fragmented QRS Waves In V5 And 6 Leads After Successful Nuss Surgery For Pectus Excavatum Considering QRS Wave Axis And Width And Heart Compression On Computed Tomography

Introduction: On ECG, fragmented QRS waves (fQRS), otherwise known as a notch in the QRS complex, may indicate conduction abnormalities. Pectus excavatum (PEX) physically depresses the heart (mainly the right and left aria (RA, LA)). The Nuss operation is a minimal invasive technique for PEX repair. Hypothesis: We hypothesize that fQRS may occur in PEX even in patients without right bundle branch block (RBBB), and that the Nuss operation would reduce these, depending on the Haller index (HI) of anatomical severity as calculated from CT imaging (CLINICS 2007; 62:599). Methods: 17 patients (14 male, 12±6 years) underwent the Nuss operation for PEX, all of which were successful. HI was significantly improved from 5.62±2.29 to 3.29±0.65 (P=0.0002). Before the Nuss operation, 6 patients had incomplete RBBB; of the 11 without RBBB, 6 (55%) had fQRS waves. We evaluated the degree of RA and LA compression in these PEX patients by CT. Results: We compared 6 patients with fQRS waves but no RBBB before surgery with 5 patients without fQRS waves but no RBBB before surgery, and only LA diameter on CT before surgery was significantly greater in the former than the latter (P=0.004) (Table). Of 6 patients with fQRS waves but no RBBB before surgery, 3 patients (50%) had de novo fQRS waves in V5 and 6 after surgery. There were no significant differences of QRS axis and width before and after surgery in these3 patients who had de novo fQRS waves in V5 and 6 after surgery. Of 5 patients without any fQRS waves but no RBBB before surgery, 4 patients (80%) had de novo fQRS waves in V5 and 6 after surgery. There were no significant differences of QRS axis and width before and after surgery in these 4 patients who had de novo fQRS waves in V5 and 6 after surgery. Conclusions: In patients with PEX, de novo fQRS waves can occur after a successful Nuss operation, especially in the V5 and V6 leads, even in patients without RBBB and without changes of QRS axis and width. This may be caused by heart rotation or some effects of the Nuss procedure.

ELECTROCARDIOGRAPHIC CHARACTERISTICS WITH LEFT BUNDLE BRANCH AREA PACING: A SINGLE CENTER PROSPECTIVE STUDY

<h3>BACKGROUND</h3> Pure left bundle branch (LBB) capture should result in typical RBBB (rsR') morphology. However, numerous paced QRS morphologies are observed during LBB area pacing (LBBAP). There are limited papers describing the various electrocardiographic (ECG) morphologies seen with LBBAP. Objective: To evaluate the various ECG characteristics encountered in LBBAP. <h3>METHODS AND RESULTS</h3> Patients referred for pacemaker implantation between 08/2019-01/2021 were considered for LBBAP. LBBAP was performed by implantation of a Medtronic 3830 lead 2 cms distal to His and confirmed by previously published criteria. Paced QRS morphology and QRS axis was analyzed. Baseline, ECG, and implantation characteristics are summarized in table 1. Of 264 LBBAP ECGs, the most common morphology seen during unipolar tip pacing was an incomplete RBBB pattern (qR) in V1 in 165 (69.9%) patients. rSR' pattern was seen in 9 (3.2%) and a narrow QS pattern in 60 (21.5%) patients. <h3>CONCLUSION</h3> Various ECG morphologies may be encountered during successful LBB area capture and are associated with similar QRSd, pacing characteristics and short-term lead performance. These morphologies are due to capture of various structures (RV or LV septum, capture of LBB, LPF +/- RBB) and are likely due to virtual-electrode effect.

B-PO05-037 ELECTROCARDIOGRAPHIC CHARACTERISTICS WITH LEFT BUNDLE BRANCH AREA PACING: A SINGLE CENTER PROSPECTIVE STUDY

Pure left bundle branch (LBB) capture should result in typical RBBB (rsR’) morphology. However, numerous paced QRS morphologies are observed during LBB area pacing (LBBAP). There are limited papers describing the various electrocardiographic (ECG) morphologies seen with LBBAP. To evaluate the various ECG characteristics encountered in LBBAP. Patients referred for pacemaker implantation between 02/2019-02/2021 were considered for LBBAP. LBBAP was performed by implantation of a Medtronic 3830 lead 2 cms distal to His and confirmed by previously published criteria. If unsuccessful, lead was repositioned distally and inferiorly on the septum to capture the left posterior fascicle (LPF). Paced QRS morphology and QRS axis was analyzed. Baseline, ECG, and implantation characteristics are summarized in table 1. Of 274 LBBAP ECGs, the most common morphology seen during unipolar tip pacing was an incomplete RBBB pattern (qR) in V1 in 131 (48%) patients. rSR’ pattern was seen in 38 (14%) and a narrow QS pattern in 34 (12.5%) patients. qR or rsR’ with left axis deviation, i.e., LPF capture was noted in 69 (25%) patients. One patient exhibited monophasic R in lead V1. Unipolar ring pacing resulted in wide QS in all patients due to RV septal capture only. Various ECG morphologies may be encountered during successful LBB area capture and are associated with similar QRSd, pacing characteristics and short-term lead performance. These morphologies are due to capture of various structures (RV or LV septum, capture of LBB, LPF +/- RBB) and are likely due to virtual-electrode effect.

Anatomical localization and classification of bundle branch blocks using novel CineECG

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This work was supported by the Dutch Heart Foundation Background Ventricular conduction disorders can induce arrhythmias and impair cardiac function. Bundle branch blocks are diagnosed by 12-lead ECG, but discrimination between complete bundle branch blocks, incomplete bundle branch blocks and normal tracings can be challenging. CineECG computes the mean temporo-spatial isochrone (mTSI) trajectory of activation waveforms in a 3D-heart model from 12-lead ECGs. This trajectory represents the mean trajectory of the ventricular electrical activation at any time interval directly related to ventricular anatomy. In Brugada patients, CineECG has localized the terminal components of ventricular depolarization to right ventricle outflow tract (RVOT). Also, for the localization of bundle branch blocks, the region of latest activation contains the most information. Using CineECG, subject specific anatomically related information about the location of bundle branch blocks is obtained. Purpose This study aimed at exploring whether CineECG can improve the discrimination between complete left/right bundle branch blocks (LBBB/RBBB), and incomplete RBBB (iRBBB). Methods We utilized 400 12-lead ECGs from the online Physionet-XL-PTB-Diagnostic ECG Database with a certified ECG diagnosis. The mTSI trajectory was calculated and projected into the anatomical 3D-heart model. Five CineECG classes were established: "Normal", "iRBBB", "RBBB", "LBBB" and "Undetermined", to which each tracing was allocated. We determined the accuracy of CineECG classification with the gold standard diagnosis. Results A total of 391 ECGs were analyzed (9 ECGs were excluded for noise) and 240/266 were correctly classified as "normal", 14/17 as "iRBBB", 55/55 as "RBBB", 51/51 as "LBBB" and 31 as "undetermined". Average mTSI trajectories were calculated according to ECG diagnosis (Figure). The terminal mTSI contained most information about the BBB localization, as that part directs to the site of latest activation (Figure, red arrow). Conclusion CineECG provided the anatomical localization of different BBBs and accurately differentiated between normal, LBBB and RBBB, and iRBBB. CineECG may aid clinical diagnostic work-up, potentially also contributing to the difficult discrimination between normal, iRBBB and Brugada patients. Abstract Figure. Average CineECG trajectories