Intraventricular Conduction Defects Research Articles

A clinical case of transthyretin amyloidosis with manifestations of seronegative arthritis

A clinical case of transthyretin amyloidosis with manifestations of seronegative arthritis

SPONTANEOUS THIRD-DEGREE ATRIOVENTRICULAR BLOCK IN A DIABETIC PATIENT PRESENTING AS RECURRENT SYNCOPE

Chronic, uncontrolled hyperglycemia is associated with an increased incidence of coronary artery disease, cardiac failure, diabetic nephropathy, diabetic retinopathy, and associated mortality. A 72-year-old female presented to the OPD with multiple episodes of loss of consciousness for the past 1 month. The patient also had other comorbidities such as hypertension, diabetes mellitus (DM), and hypothyroidism. On systemic examination, her blood pressure was 124/77 mmHg (supine) and 116/72 mmHg (standing), and her pulse rate was 56 beats/min. She had a loss of vibration sense in both lower limbs up to the ankle. Fundus examination showed non-proliferative diabetic retinopathy. The rest of the systemic examination was clinically normal. Her HbA1C was 8.1%, and other routine investigations were within normal limits. Electrocardiography (ECG) showed sinus bradycardia. Echocardiography showed normal ventricular function with no evidence of ischemic heart disease (IHD). 24-h Holter ECG revealed sinus bradycardia with an intraventricular conduction defect, a third-degree AV block with junctional beats, and rare supraventricular ectopics. This is a case of Type 2 DM with complete heart block (CHB) of spontaneous onset. Other causes of AV block have been ruled out, and it seems that this case of CHB is possibly due to cardiac autonomic neuropathy (CAN). Multiple factors, such as the duration of diabetes, poor glycemic control, metabolic derangements, and genetic factors, determine CAN. This case emphasizes that patients with type 2 diabetes without IHD can develop CHB spontaneously.

P404 MYOCARDIAL WORK EVALUATION IN PATIENTS WITH SEVERE AORTIC STENOSIS UNDERGOING TRANSCATHETER AORTIC VALVE REPLACEMENT

Abstract Background myocardial work (MW) is a novel echocardiographic technique that enables the study of left ventricular performance. It overcomes speckle tracking echocardiography (STE) limitations, dependent on afterload, which is increased in patients with severe aortic stenosis (AS). Aims: To evaluate myocardial performance indexes obtained with MW in patients with AS and indication to percutaneous aortic valve replacement (TAVR) before and after the procedure. Methods patients with severe AS and preserved left ventricular systolic function (LVEF) and indication to TAVR underwent complete echocardiographic evaluation the day before and within two days after the procedure. MW indices were calculated considering noninvasive systolic blood pressure (SBP) and corrected for the mean transvalvular aortic gradient. Results 39 patients (78±6 years, 61.5% women) were enrolled, they presented at baseline preserved LVEF (59.4±8.2%) and reduced global longitudinal strain (GLS) (–16.8±3.3%). Corrected global work index (cGWI) and corrected global constructive work (cGCW) appeared elevated before the procedure, and were significantly reduced within 2 days after TAVR (cGWI –2460.5±839.7 mmHg% vs 1844.4±521.6 mmHg%, p<0.01; cGCW 3061.3 ± 796.0 vs 2277.4 ± 536.5mmHg%, p<0.01). Adjusted global wasted work (cGWW) and adjusted global work efficiency (cGWE) did not change significantly after TAVR (cGWW 262.6±151.8 vs 244.2±129.2 mmHg%, p=0.236; cGWE 90.1±4.5 vs 88.5±5.2%, p=0.079) in the overall population. In the subgroup of patients who had not developed new atrioventricular or intraventricular conduction abnormalities, cGWW also significantly decreased following TAVR (275±152.6 vs 216.3 ± 99.7 mmHg%, p=0.018), with no change in cGWE (89.7±4.8 vs 89.3±5.8%, p=0.838). Conclusions The reduction in cGWI and cGWC values and thus myocardial oxygen consumption in the immediate post–TAVR is attributable to the reduction in afterload. Left ventricular function abnormalities do not totally regress after the procedure, although the lack of reduction in cGWW could be partly due to the development of atrioventricular or intraventricular conduction defects. Further studies are desirable to define a role of MW in prognostic stratification of patients with severe AS.

Electrocardiographic Waveform Abnormalities in Patients With Structural Heart Disease

Scenario: This 12-lead electrocardiogram (ECG) was obtained in a 72-year-old man arriving in the emergency department with shortness of breath and dizziness. Prior medical history includes myocardial infarction (MI), heart failure (HF), chronic obstructive pulmonary disease (COPD), diabetes (type 2), and paroxysmal atrial fibrillation. Current prescribed medications include a β-blocker, aspirin, angiotensin-converting enzyme inhibitor, furosemide, and diltiazem. His blood pressure was 98/50 mm Hg, respiratory rate 24/min, and oxygen saturation as measured by pulse oximetry (Spo2) was 92% on 3 L of oxygen. He was most comfortable sitting up with his arms on the bedside table, and said he felt better after 40 mg of furosemide was administered intravenously.Sinus rhythm with premature atrial complexes (PACs), possible right and left atrial enlargement, prior inferior wall MI (q waves in leads III and aVF), incomplete left intraventricular conduction defect (fQRS waves), left ventricular hypertrophy, and ST-segment and T-wave abnormalities may suggest anterolateral ischemia.Although the underlying rhythm is irregular, suggesting atrial fibrillation, P waves are visible before every QRS complex; thus, this is sinus rhythm with frequent PACs. PACs are not uncommon in patients with structural heart disease and COPD, like this one. The pause after the PACs is a normal physiologic response and represents a compensatory pause associated with PACs. The ECG criterion for right atrial enlargement is a P-wave amplitude greater than 2.5 mm in leads II, III, and aVF (so-called P pulmonale) and can be seen with COPD. Left atrial enlargement is due to pressure or volume overload of the left atrium and can be assessed in V1 (biphasic P waves with negative terminal portion >40 ms long and >1 mm deep). Biatrial enlargement is consistent with this patient’s medical history (MI, HF, and left ventricular hypertrophy); however, ECG is not the reference standard method, so the diagnosis should be confirmed by echocardiography. The T-wave inversion and ST-segment depression most likely represent a “strain” pattern seen with left ventricular hypertrophy, but acute myocardial ischemia should be ruled out given the patient’s prior MI.Immediate management includes addressing the acute respiratory distress and low blood pressure, with HF exacerbation a likely source. This patient’s symptoms were somewhat relieved after the intravenous furosemide, which supports this diagnosis. Checking a venous blood sample for brain natriuretic peptide (BNP) to assess for HF, troponin to rule out myocardial ischemia, and electrolyte levels would help. A chest radiograph would be useful, as might arterial blood gas analysis, given his elevated rate of breathing and the 92% Spo2 with 3 L of oxygen. Findings on physical examination, especially lung and heart sounds, peripheral edema, and daily weight should be evaluated. Ultimately, this patient’s BNP level was 3400 ng/mL, which corroborates HF, and his troponin was negative for myocardial ischemia. He was discharged home 3 days later.

Baseline Electrocardiographic Abnormalities in Pre-Treatment Cancer Compared With Non-Cancer Patients: A Propensity Score Analysis.

Most studies have compared post-treatment electrocardiogram (ECG) abnormalities in cancer patients to the general population. To assess baseline cardiovascular (CV) risk, we compared pre-treatment ECG abnormalities in cancer patients with a non-cancer surgical population. We conducted a combined prospective (n = 30) and retrospective (n = 229) cohort study of patients aged 18 - 80 years with diagnosis of hematologic or solid malignancy, compared with 267 pre-surgical, non-cancer, age- and sex-matched controls. Computerized ECG interpretations were obtained, and one-third of the ECGs underwent blinded interpretation by a board-certified cardiologist (agreement r = 0.94). We performed contingency table analyses using likelihood ratio Chi-square statistics, with calculated odds ratios. Data were analyzed after propensity score matching. The mean age of cases was 60.97 ± 13.86; and 59.44 ± 11.83 years for controls. Pre-treatment cancer patients had higher likelihood of abnormal ECG (odds ratio (OR): 1.55; 95% confidence interval (CI): 1.05 to 2.30), and more ECG abnormalities (χ2 = 4.0502; P = 0.04) compared with non-cancer patients. ECG abnormalities were higher in black compared to non-black patients (P = 0.001). In addition, baseline ECGs among cancer patients prior to cancer therapy demonstrated less QT prolongation and intra-ventricular conduction defect (P = 0.04); but showed more arrhythmias (P < 0.01) and atrial fibrillation (AF) (P = 0.01) compared with the general patient population. Based on these findings, we recommend that all cancer patients receive an ECG, a low-cost and widely available tool, as part of their CV baseline screening, prior to cancer treatment.

Oxidative stress and adverse cardiovascular effects among professional divers in Egypt

Professional divers are exposed to unique multifactorial hazards in their working environment and adverse cardiovascular effects such as ischemia, arrhythmia, stroke, and death are associated with professional diving. Cardiovascular events are aggravated by diving-induced oxidative stress and account for one-fourth of diving fatalities. This study aimed to measure oxidative and cardiovascular stress in a group of professional divers in Alexandria, Egypt using a panel of biomarkers. A comparative cross-sectional study was conducted between June 2017 and May 2018 at the General Naval Hospital in Alexandria. A total of 50 professional divers and a comparison group of 50 marine seafarers sharing similar maritime environments were enrolled in the study. Participants were clinically evaluated by electrocardiography (ECG) and plasma measurement of trace metals (Fe+, Cu+, and Zn+), electrolytes (Na+, K+, Ca+), and oxidative stress biomarkers (OSBMs; MDA, TAS, GST, GSH, GR, GPx, SOD, and CAT). Significant ECG abnormalities including short corrected QT interval, sinus bradycardia, left ventricular hypertrophy, early repolarization, first-degree heart block, and intraventricular conduction defect were identified among divers. Biochemical analyses revealed high mean levels of FBG [89.0 ± 12.46 vs. 100.5 ± 29.03 mg/dl], LDH-C [41.46 ± 4.01 vs. 39.34 ± 4.34 mg/dl], electrolyte imbalance [higher Na+ (9.44 ± 0.52 vs. 9.19 ± 0.60 mmol/L), and lower Ca+ (141.72 ± 3.53 and 143.26 ± 3.99 mmol/L)], disturbed trace metals [Fe+ and Zn+ (101.1 ± 38.17 vs. 147.6 ± 38.08 and 85.52 ± 27.37 vs. 116.6 ± 21.95 µm/dl, respectively), higher Cu+ (271.3 ± 75.01 vs. 100.8 ± 30.20 µm/dl)], and higher OSBMs (high MDA and reduced CAT, GPx, GSH, GR, and GST enzyme levels) among professional divers compared to the marine seafarers (t-test p < 0.05). Oxidative stress and trace metal imbalance are associated with the pathophysiology of cardiovascular disease; this association, together with electrophysiological changes of ECG may serve as biomarkers for cardiovascular risk assessment in diver periodic medical examinations.

Atrial depolarization abnormalities in pulmonary sarcoidosis

BackgroundCardiac sarcoidosis, often manifested as sudden death, can be the first manifestation of sarcoidosis. Since 12-lead electrocardiogram (ECG) is recommended as an initial screening tool for cardiac sarcoidosis, the recognition of subtle abnormalities assumes utmost significance. The objective of this study was to identify the electrocardiographic abnormalities in patients with pulmonary sarcoidosis.ResultsA detailed analysis of 12-lead ECGs obtained from sixty patients with histopathologically proven pulmonary sarcoidosis and no overt cardiac involvement was done. The findings were compared with those of an age-matched control group. Varying degrees of intraventricular conduction defects were common in the study group [67%], as well as the control group [57%] [P = 0.23]. There was a higher prevalence of biphasic P wave [P = 0.003] and bifid P wave [P = 0.029] in lead III and rsr’ in lead aVF [P = 0.03] in the study group as compared to the control group.ConclusionsOur study demonstrates a greater prevalence of subtle ECG abnormalities in patients with pulmonary sarcoidosis as compared to patients with other forms of pulmonary disease. Atrial depolarization abnormalities were commoner in patients with pulmonary sarcoidosis.

Electrocardiographic Abnormalities predicting mortality in COVID-19 pneumonia patients.

ABSTRACTBackground:Cardiovascular involvement is a significant cause of death in COVID pneumonia. Early electrocardiographic changes may predict cardiovascular involvement and predict mortality in COVID pneumonia patientsMethods:A total of 250 consecutive patients with COVID-19 pneumonia admitted to the emergency were studied for electrocardiographic abnormalities and their relation to mortalityResults:Most patients required supplemental oxygen to maintain optimal saturation. A total of 72% showed ECG abnormalities, and the overall cohort had a mortality of 50%. New-onset atrial fibrillation, left bundle branch block or right bundle branch pattern, and ventricular premature complexes were associated with high mortality. Sinus tachycardia and atrial fibrillation were the most common arrhythmia and were significantly associated with mortalityConclusions:New-onset atrial fibrillation, intraventricular conduction defects, and sinus tachycardia are associated with increased mortality in COVID pneumonia patients.

Comprehensive non-invasive assessment of electrocardiographic abnormalities and cardiac arrhythmias in patients with genetically confirmed mitochondrial diseases

BackgroundThere is limited data on cardiac arrhythmias and ventricular repolarization and dispersion abnormalities in patients with mitochondrial diseases (MitD). MethodsConsecutive 40 patients with genetically proven MitD and 35 healthy controls were studied. Among other examinations all subjects underwent 24-h Holter recording and 12‑lead electrocardiography (ECG) with corrected QT (QTc), QT dispersion (QTd), Tp-e and Tp-e/QT ratio assessment. ResultsPatients with MitD were 55.4 ± 15.7 years old, the disease duration was 18.5 ± 10.3 years, presented 6 clinical syndromes while mitochondrial and nuclear DNA type of mutation was present in 40 and 60% of cases, respectively. In MitD more frequently 1st degree atrioventricular block and intraventricular conduction defects were observed and also QRS complex duration was increased. Mean values of QTc (p = 0.001), QTd (p = 0.02), Tp-e (p < 0.00001) and Tp-e/QT (p < 0.00001) were significantly higher in MitD than in controls. Correlations between disease duration and PR interval duration (p = 0.003) and Creatine Kinase MB isoenzyme activity (p = 0.02) were found. No differences in depolarization and dispersion parameters were observed according to type of mutation or dominant clinical syndromes. In addition to supraventricular extrasystoles, nonsustained supraventricular tachycardias occurred more frequently in MitD (in 45.0 vs 14.3%, p = 0.0004). Ventricular arrhythmias were rare and observed almost exclusively in subjects with mitochondrial DNA mutation. ConclusionsIn contrast to healthy controls, in MitD patients intraventricular, repolarization and dispersion disturbances were more frequently observed. In addition to bradyarrhythmias observed in some defined MitD syndromes, supraventricular rather than ventricular arrhythmias are more common.

Progressive involvement of cardiac conduction system in paediatric patients with Kearns-Sayre syndrome: how to predict occurrence of complete heart block and sudden cardiac death?

The aims of this study are to evaluate the progressive involvement of the cardiac conduction system in the Kearn-Sayre syndrome (KSS) and to establish criteria for the prevention of episodes of syncope or sudden cardiac death. This is a prospective monocentric study including KSS patients, with diagnosis based on clinical manifestations, muscle biopsy, and genetic tests, before the age of 18. All patients underwent cardiac screening examination with 12-lead electrocardiogram (ECG), 24-h Holter monitoring, and pacemaker (PM) interrogation twice a year. Fifteen patients (nine males, mean age 16.6 ± 3.9 years) with a sporadic KSS were recruited. All subjects manifested at least one of the intraventricular conduction defects (IVDs): 1 right bundle branch block (RBBB), 2 left anterior fascicular block (LAFB), 11 a bi-fascicular block (RBBB + LAFB), and 1 left posterior fascicular block. Most children with bi-fascicular block developed LAFB before the RBBB (P = 0.0049). In six patients, IVD degenerated into atrioventricular block (AVB). Endocavitary PM was implanted in 11 patients (6 with AVB and 5 with a bi-fascicular block), while an implantable cardioverter-defibrillator only in one patient with a non-sustained ventricular tachycardia. Four died at mean age of 14.7 ± 2.6 years, but none of them suddenly. Even a 'simple' ECG can predict the arrhythmic risk and the occurrence of catastrophic events in young patients with KSS. Left anterior fascicular block precedes RBBB in determining the bi-fascicular block and this can predict an inexorable progression of the conduction defects even in a short time. Pacemaker implantation may be indicated in these patients since the first bi-fascicular block manifestation.

Initial Experience, Safety, and Feasibility of Left Bundle Branch Area Pacing

This study sought to evaluate the safety and feasibility of conduction system pacing by performing left bundle branch area pacing (LBBAP).There are limited data from single centers showing that LBBAP may circumvent the technical and electrophysiological challenges encountered with His bundle pacing.Patients referred for pacemaker implantation at 2 centers between February 1, 2019, and March 31, 2020, were considered for LBBAP. LBBAP was performed by implanting a lumen-less, exposed helix lead approximately 2 cm distal to the His bundle and deep into the septum using a specialized delivery sheath. Implant success rates, complications, and electrophysiological parameters were assessed.LBBAP was successful in 305 of 341 patients (89%). Mean age was 72 ± 12 years; 45% were women; and 39% had QRS duration (QRSd) >130 ms, 22% right bundle branch block, 11% left bundle branch block, and 6% intraventricular conduction defect. Pacing indications were sinus node dysfunction in 28.7%, atrioventricular block in 52.5%, cardiac resynchronization therapy in 8.8%, and refractory atrial fibrillation in 10% of patients. Procedural duration was 74.7 ± 34 min and fluoroscopic time was 10.4 ± 8.1 min. The mean baseline QRSd and paced QRSd in the overall cohort was 114 ± 29.8 ms versus 112 ± 11.7 ms (p < 0.001) and in patients with infra-Hisian disease was 144.5 ± 19 ms versus 115 ± 12 ms (p < 0.001), respectively. Mean left ventricular activation time was 71.7 ± 11 ms at high output and 74.7 ± 11 ms at low output. LBB potentials were noted in 41% patients. Pacing threshold and R waves were 0.74 ± 0.3 V at 0.4 ms and 10.7 ± 4.9 mV at time of implantation and were stable at 1-, 3-, 6-, and 12-month follow-ups. The only major complications were 3 LBBAP lead dislodgements, 2 within 24 h and 1 at 2 weeks.LBBA pacing is safe, feasible, and a reliable alternative to His bundle pacing for providing physiological pacing. Randomized controlled studies are needed to confirm the safety, feasibility, and clinical outcomes of LBBAP.

Right Sided Precordial Leads Electrocardiographic Mapping in Normal Individuals and in Patient with Acute Myocardial Infarction and Various Intra Ventricular Conduction Defect

Right Sided Precordial Leads Electrocardiographic Mapping in Normal Individuals and in Patient with Acute Myocardial Infarction and Various Intra Ventricular Conduction Defect

Upgrade of cardiac resynchronization therapy by utilizing additional His-bundle pacing in patients with inotrope-dependent end-stage heart failure: a case series.

BackgroundHis-bundle pacing (HBP) alone may become an alternative to conventional cardiac resynchronization therapy (CRT) utilizing right ventricular apical (RVA) and left ventricular (LV) pacing (BiVRVA+LV) in selected patients, but the effects of CRT utilizing HBP and LV pacing (BiVHB+LV) on cardiac resynchronization and heart failure (HF) are unclear.Case summaryWe presented two patients with inotrope-dependent end-stage HF in whom the upgrade from conventional BiVRVA+LV to BiVHB+LV pacing by the addition of a lead for HBP improved their HF status. Patient 1 was a 32-year-old man with lamin A/C cardiomyopathy, atrial fibrillation, and complete atrioventricular (AV) block. Patient 2 was a 70-year-old man with ischaemic cardiomyopathy complicated by AV block and worsening of HF resulting from ablation for ventricular tachycardia storm. The HF status of both patients improved dramatically following the upgrade from BiVRVA+LV to BiVHB+LV pacing.DiscussionEnd-stage HF patients suffer from diffuse intraventricular conduction defect not only in the LV but also in the right ventricle (RV). The resulting dyssynchrony may not be sufficiently corrected by conventional BiVRVA+LV pacing or HBP alone. Right ventricular apical pacing itself may also impair RV synchrony. An upgrade to BiVHB+LV pacing could be beneficial in patients who become non-responsive to conventional BiV pacing as the His–Purkinje conduction defect progresses.

Intraventricular conduction defects in patients with st-segment elevation myocardial infarction – the paradox of right bundle branch block

Abstract Intraventricular conduction defects (IVCD) in patients with acute myocardial infarct (AMI) are predictors of a worse prognosis. When acquired they can be the result of an extensive myocardial damage. Purpose To assess the impact of IVCD, regardless of being previously known or presumed new, on in-hospital outcomes of patients with AMI with ST segment elevation (STEMI) or undetermined location. Methods From a series of patients included in the National Registry of Acute Coronary Syndrome between 10/1/2010 and 9/1/2019, were selected patients with STEMI or undetermined AMI, undergoing coronary angiography. Results 7805 patients were included: 461 (5.9%) presenting left bundle branch block (LBBB), 374 (4.8%) with right bundle branch block (RBBB) and 6970 (89.3%) with no IVCD. Clinical characteristics as well as in-hospital outcomes are described in the table 1. An unexpected worse prognosis in patients with RBBB has motivated a multivariate analysis. RBBB remained an independent predictor of in-hospital mortality (OR 1.91, 95% CI 1.04–3.50, p=0.038), along with female gender (OR 1.73, 95% CI 1.11–2.68, p=0.015), Killip Class&amp;gt;1 (OR 2.26, 95% CI 1.45–3.53, p&amp;lt;0.001), left ventricular ejection fraction &amp;lt;50% (OR 3.93, 95% CI 2.19–7.05, p&amp;lt;0.001) and left anterior descending artery as the culprit lesion (OR 1.85, 95% CI 1.16–2.91, p=0.009). Conclusion In spite of an apparent better clinical profile, in the current large series of unselected STEMI patients, the presence of RBBB is associated with the worst in-hospital outcome. RBBB doubles the risk of death, being an independent predictor of in-hospital mortality. Funding Acknowledgement Type of funding source: None

Incidence and predictors of total mortality in 267 adults presenting with mitochondrial diseases.

Assessing long-term mortality and identifying predictors of death in adults with mitochondrial diseases. We retrospectively included adult patients with genetically proven mitochondrial diseases referred to our centre between January 2000 and June 2016, and collected information relative to their genetic testing, clinical assessments, and vital status. We performed single and multiple variable analyses in search of predictors of total mortality, and calculated hazard ratios (HR) and 95% confidence intervals (CI). We included 267 patients (women 59%; median age 43.3 [31.3-54.2] years), including 111 with mitochondrial DNA (mtDNA) single large-scale deletions, 65 with m.3243A>G, 24 with m.8344A>G, 32 with other mtDNA point mutations, and 36 patients with nuclear genes mutations. Over a median follow-up of 8.9 years (0.3 to 18.7), 61 patients (22.8%) died, at a median age of 50.7 (37.9-51.9) years. Primary cause of death was cardiovascular disease in 16 patients (26.2%), respiratory in 11 (18.0%), and gastrointestinal in 5 (8.1%). By multiple variable analysis, diabetes (HR 2.75; 95% CI 1.46-5.18), intraventricular cardiac conduction defects (HR 3.38; 95% CI 1.71-6.76) and focal brain involvement (HR 2.39; 95% CI 1.25-4.57) were independent predictors of death. Adult patients with mitochondrial diseases present high morbidity that can be independently predicted by the presence of diabetes, intraventricular cardiac conduction defects, and focal brain involvement.

Right Sided Precordial Leads Electrocardiographic Mapping in Normal Individuals and in Patients with Acute Myocardial Infarction and Various Intraventricular Conduction Defects

Right Sided Precordial Leads Electrocardiographic Mapping in Normal Individuals and in Patients with Acute Myocardial Infarction and Various Intraventricular Conduction Defects

Do all intra-ventricular conduction defect ECG patterns respond equally to CRT?

Response to cardiac resynchronization therapy (CRT) is well-established in patients with typical left bundle branch block (LBBB) but modest or even negative in those with intraventricular conduction delay (IVCD). However, IVCD pattern is heterogeneous, and it is possible that QRS patterns may also respond to CRT. Consecutive baseline ECGs of 239 patients implanted between 2007 and 2010 with CRT were analyzed. ECGs were classified into the following three groups: (a) typical LBBB (TLBBB) according to accepted guidelines (n= 67); (b) IVCD with LBBB pattern criteria in V1, 1, and aVL but with QS or rS in V5-V6 which we defined as atypical LBBB (ALBBB) (n= 74); and (c) all other IVCD (OIVCD) patterns (n= 98). Endpoints were 2years mortality and echocardiographic response, defined as a decrease of ≥ 10% in indexed LVESV or an increase of ≥ 5% in left ventricular ejection fraction at 1year of follow-up. Baseline clinical characteristics were similar among all the three groups. Rates of echocardiographic response were lower among those with OIVCD compared to those with LBBB and ALBBB (50% vs. 75% and 72%, respectively, p= 0.01 for both comparisons). A multivariable model showed a lower likelihood of echocardiographic response in OIVCD [HR = 0.40; (0.16-0.98)] and a similar likelihood in ALBBBB [HR = 0.98; (0.40-2.40)] compared to TLBBB. Cumulative 2-year survival was 88% in ALBBB, 86% in TLBBB, and 76% in OIVCD (p value = 0.011). Patients with ALBBB may have a favorable echocardiographic response to CRT and display similar survival rates to typical LBBB. This subgroup of IVCD should be considered for CRT. Atypical left bundle branch morphology defined as QS or rS in lead V1, broad R waves in lead I, and aVL but with QS or rS in V5-V6 is associated with favorable echocardiographic response to CRT and displays similar survival rates to typical LBBB patients.

Prospective evaluation of feasibility and electrophysiologic and echocardiographic characteristics of left bundle branch area pacing

His bundle pacing (HBP) is the most physiologic form of pacing but associated with higher thresholds and lower success in patients with His-Purkinje conduction disease. Recent reports have described transvenous left bundle branch area pacing (LBBAP). We aimed to prospectively evaluate the feasibility and the electrophysiologic and echocardiographic characteristics of LBBAP. Patients requiring pacing for bradycardia or heart failure indications (failed left ventricular [LV] lead) were prospectively enrolled. LBBAP was performed with a Medtronic 3830 lead. Presence of left bundle branch (LBB) potential, paced QRS morphology/duration, and peak LV activation time (pLVAT) were recorded at implant. Pacing threshold and sensing was assessed at implant and follow-up. Echocardiography was performed to assess the approximate lead location and impact on tricuspid valve function. LBBAP was successful in 93 of 100 (93%) patients. Mean age was 75 ± 13 years; men 69%, left bundle branch block 24%, right bundle branch block 25%, intraventricular conduction defect 8%. Indications for pacing were atrioventricular (AV) block 54%, sinus node dysfunction 23%, AV node ablation 7%, cardiac resynchronization therapy 11%, HBP lead failure 7%. Baseline QRS duration was 133 ± 35 ms. Paced QRS duration was 136 ± 17 ms. LBB potentials were observed in 63 patients with left bundle branch - ventricle (LBB-V) interval of 27 ± 6 ms. pLVAT was 75 ± 16 ms. Pacing threshold at implant was 0.6 ± 0.4 V @ 0.5 ms and R waves were 10 ± 6 mV and remained stable at median follow-up of 3 months. The lead depth in the septum was approximately 1.4 ± 0.23 cm. LBBAP was feasible in a high percentage of patients with low thresholds during acute follow-up. HBP and LBBAP may significantly increase the overall success of physiologic pacing.

His-Optimized Cardiac Resynchronization Therapy to Maximize Electrical Resynchronization: A Feasibility Study.

Background Cardiac resynchronization therapy (CRT) is an established therapy for patients with cardiomyopathy, left bundle branch block, and heart failure. His bundle pacing (HBP) may also improve clinical outcomes by narrowing QRS duration. The QRS narrowing by HBP may not always be optimal. The aim of the study was to determine if CRT could be optimized by sequential HBP followed by left ventricular (LV) pacing (His-Optimized CRT [HOT-CRT]) to maximize electrical resynchronization. Methods We attempted permanent HBP in 27 patients (left bundle branch block 17, intraventricular conduction defect 5, and right ventricular pacing 5) referred for CRT in addition to LV lead. HBP was followed by LV pacing at a delay equal to His-ventricular interval. QRS duration at baseline, during HBP, biventricular pacing, and HOT-CRT was measured. Echocardiographic parameters and New York Heart Association functional class were assessed at baseline and during follow-up. Results HOT-CRT was successful in 25 of 27 patients (age 72±15 years, men 23, ischemic 21). QRS duration at baseline was 183±27 ms and significantly narrowed to 162±17 ms with biventricular pacing ( P=0.003), to 151±24 ms during HBP ( P<0.0001), and further to 120±16 ms during HOT-CRT ( P<0.0001). During a mean follow-up of 14±10 months, LV ejection fraction improved from 24±7% to 38±10% ( P<0.0001), and New York Heart Association functional class changed from 3.3 to 2.04. Twenty-one of 25 patients (84%) were clinical responders while 23 of 25 (92%) showed echocardiographic response. Conclusions In this feasibility cohort, HOT-CRT resulted in improved electrical resynchronization. HOT-CRT may improve clinical and echocardiographic outcomes in advanced heart failure patients requiring CRT.

Severe Bradycardia Prior to Coronary Artery Bypass Graft Surgery: A Case Report

Intraventricular conduction abnormalities following cardiac surgery have been thoroughly described, especially after valvular surgery. It is also widely known that several anesthetic factors can cause autonomic disturbances resulting in the unmasking of sinus node dysfunction, significant bradycardia, and cardiovascular collapse during the intraoperative period. However, little is known about asymptomatic episodes, especially those occurring prior to coronary artery bypass grafting (CABG). We report a rare occurrence of an intraventricular conduction defect that presented in an asymptomatic patient following non-ST-elevation myocardial infarction prior to urgent CABG. Our patient presented with sudden-onset chest pain, and following coronary angiography he was found to have triple-vessel coronary disease. During anesthetic induction for inpatient CABG surgery, he developed episodes of acute sinus tachy-brady episodes, requiring a stat dose of adrenaline to maintain the heart rate prior to the establishment of cardiopulmonary bypass. The arrhythmia persisted postoperatively, necessitating the insertion of a permanent dual-chamber pacemaker for complete heart block. The patient was later discharged without further complications, and upon follow-up 12 months later, he remains in good health.