High-degree atrioventricular block, asystole, and electro-mechanical dissociation complicating non-ST-segment elevation myocardial infarction

Occurrence of Severe Arrhythmias in Patients with Non-ST Elevation Acute Coronary Syndrome (NSTE-ACS): A Retrospective Study

BACKGROUND

Non-ST elevation acute coronary syndrome (NSTE-ACS) is one of the most frequent manifestations of coronary artery disease. The occurrence of serious heart rhythm disorders (SHRDs) in NSTE-ACS is not well documented. However, continuous heart rhythm monitoring is recommended during the initial management of NSTE-ACS. The targeted monitoring of patients at greater risk for SHRDs could facilitate patients' care in emergency departments (EDs) where the flow of patients is continuously increasing.

METHODS

This retrospective single-center study included 480 patients from emergency and cardiology departments within the Strasbourg University Hospital between 1 January 2019 and 31 December 2020. The objective was to estimate the frequency of the occurrence of SHRDs among patients with NSTE-ACS. The secondary objective was to highlight the factors associated with a higher risk of SHRDs.

RESULTS

The proportion of SHRDs during the first 48 h of hospital care was 2.3% (CI95%: 1.2-4.1%, n = 11). Two time periods were considered: before coronary angiography (1.0%), and during, or after coronary angiography (1.3%). In the first group, two patients required immediate treatment (0.4% of the patients) and no death occurred. In the univariate analysis, the variables significantly associated with SHRDs were age, anticoagulant medication, a decrease in glomerular filtration rate, plasmatic hemoglobin, and left ventricle ejection fraction (LVEF), and an increase in plasmatic troponin, BNP, and CRP levels. In the multivariable analysis, plasmatic hemoglobin > 12 g/dL seemed to be a protective factor for SHRDs.

CONCLUSIONS

In this study, SHRDs were rare and, most often, spontaneously resolved. These data challenge the relevance of systematic rhythm monitoring during the initial management of patients with NSTE-ACS.

Clinical impact of complete atrioventricular block in patients with ST-segment elevation myocardial infarction

Complete atrioventricular block (CAVB) is a common complication of ST-segment elevation myocardial infarction (STEMI). Although STEMI patients complicated with CAVB had a higher mortality in the thrombolytic era, little is known about the impact of CAVB on STEMI patients who underwent primary percutaneous coronary intervention (PCI). The study aimed at evaluating the clinical impact of CAVB on STEMI patients in the primary PCI era. We consecutively enrolled 1295 STEMI patients undergoing primary PCI within 24 hours from onset. Patients were divided into two groups according to the infarct location: anterior STEMI (n = 640) and nonanterior STEMI (n = 655). The outcomes were all-cause death and major adverse cardiocerebrovascular events (MACCE) with a median follow-up period of 3.8 (1.7-6.6) years. Eighty-one patients (6.3%) developed CAVB. The incidence of CAVB was lower in anterior STEMI patients than in nonanterior STEMI (1.7% vs 10.7%, p < .05). Anterior STEMI patients with CAVB had a higher incidence of all-cause deaths (82% vs 20%, p < .05) and MACCE (82% vs 25%, p < .05) than those without CAVB. Although higher incidence of all-cause deaths was found more in nonanterior STEMI patients with CAVB compared with those without CAVB (30% vs 18%, p < .05), there was no significant difference in the incidence of MACCE (24% vs 19%). Multivariate analysis showed that CAVB was an independent predictor for all-cause mortality and MACCE in anterior STEMI patients, but not in nonanterior STEMI. CAVB is rare in anterior STEMI patients, but remains a poor prognostic complication even in the primary PCI era.

Frequency and Significance of High-Degree Atrioventricular Block and Sinoatrial Node Dysfunction in Patients With Non-ST-Elevation Myocardial Infarction

Characteristics of conduction disorders after ST-elevation myocardial infarction (STEMI) have been well described. In contrast, limited data are available on the incidence, treatment trends, and prognostic impact of conduction disorders after non-ST-elevation myocardial infarction (NSTEMI). Using the National Inpatient Sample database, we compared the characteristics and outcomes of conduction disorders in patients with a primary diagnosis of STEMI versus NSTEMI between 2010 and 2014. Conduction disorders were classified into‬ high-degree AV block (HDAVB), consisting of complete AV block or Mobitz type II second-degree AV block, and sinoatrial node dysfunction (SND). We identified 135,468 STEMI patients and 281,928 NSTEMI patients. In contrast to the STEMI cohort where HDAVB was more common than SND (2.4% vs 0.5%), SND was observed more often in the NSTEMI cohort, presenting in 2,417 patients (0.9%), followed by HDAVB in 1,745 patients (0.6%). In patients who developed HDAVB, NSTEMI patients were more likely to undergo permanent pacemaker implantation than STEMI patients (30.0% vs 11.6%; p < 0.001). The rate of permanent pacemaker implantation for SND was comparable between STEMI and NSTEMI patients (33.9% vs 30.5%; p = 0.10). In the NSTEMI cohort, patients who developed HDAVB had higher in-hospital mortality than those without any major conduction disorders (16.6% vs 3.8%; p < 0.001). In conclusion, SND was more common than HDAVB in the NSTEMI cohort, in contrast to the predominance of HDAVB observed in the STEMI cohort. About one-third of patients who developed HDAVB after NSTEMI underwent pacemaker implantation, suggesting lower rates of spontaneous resolution of HDAVB, when compared with STEMI patients.

A Case of Atrioventricular Block Potentially Associated with Right Coronary Artery Lesion and Ticagrelor Therapy Mediated by the Increasing Adenosine Plasma Concentration

Purpose

To report a case of atrioventricular block (AVB) which might be associated with the right coronary artery lesion and the novel oral antithrombotic drug ticagrelor mediated by the increasing adenosine plasma concentration (APC).

Case Report

A 65-year-old man was given loading dose of ticagrelor (180 mg) before coronary angiography with total thrombotic occlusion of right coronary artery and one stent was implanted. On second day after successful percutaneous coronary intervention, ECG monitoring showed second-degree (Mobitz type I) AVB with prolonged PR interval (299 ms). Hypothesis was drawn that elevated APC levels caused by ticagrelor would be the reason for AVB after excluding combination drugs or underlying disease. APC might be an indicator of this side effect caused by the P2Y12 receptor inhibitors. On fourth day after shifting to clopidogrel, the ECG showed normal sinus rhythm and PR interval depressed to 190 ms and APC dropped from 1.62 umol/L to 0.92 umol/L. The bradycardia and AVB did not occur in the three-month follow-up.

Conclusion

It was important to take the ticagrelor induced bradycardia into account particularly with the myocardial infarction of right coronary artery, treated with atrioventricular block drugs after initiating ticagrelor. Also, we should shift ticagrelor to clopidogrel if AVB occurred.

Severe brady-arrhythmias in systemic lupus erythematosus: prevalence, etiology and associated factors

Background

Severe brady-arrhythmias, requiring a permanent pacemaker (PPM), have been sparsely reported in systemic lupus erythematosus (SLE). The aim of this study was to describe the characteristics of such arrhythmias in a defined lupus cohort.

Patients and methods

The database of the Toronto Lupus Clinic ( n = 1366) was searched for patients who received a PPM. Demographic, clinical, immunological and therapeutic variables along with electrocardiographic (ECG) and echocardiographic findings (based on the last available test prior to PPM) were analyzed. Patients with a PPM (cases) were compared with age-, sex- and disease duration-matched patients without a PPM (controls). Analysis was performed with SAS 9.0; p < 0.05 was considered significant.

Results

Eighteen patients were identified, 13 (0.95%) with complete atrioventricular block and 5 (0.37%) with sick sinus syndrome. Disease duration at PPM implantation was 22 ± 12 years. Compared to controls, cases had more frequently coronary artery disease, hypertension, dyslipidemia and longer antimalarial (AM) treatment duration. The prevalence of first-degree atrioventricular block, right bundle branch block, left anterior fascicular block and septal hypertrophy was also higher. AM treatment was significantly associated with brady-arrhythmias (OR = 1.128, 95% CI = 1.003–1.267, p = 0.044). Nine patients had prior heart disease and one received a PPM two years after renal transplantation. Eight patients did not have any potential risk factors; prolonged AM therapy (mean 22 years) might have been the cause.

Conclusions

Apart from known causes, prolonged AM treatment may be associated with severe brady-arrhythmias in SLE. Certain ECG and echocardiographic characteristics may represent indicators of an ongoing damage in the conduction system.

Relation of elevated serum uric acid levels to first-degree heart block and other cardiac conduction defects in hospitalized patients with type 2 diabetes

AIMS

Several studies have reported that moderately elevated serum uric acid levels are associated with an increased risk of tachyarrhythmias (mainly atrial fibrillation) in patients with and without type 2 diabetes mellitus (T2DM). It is currently unknown whether an association also exists between elevated serum uric acid levels and cardiac conduction defects in patients with T2DM.

METHODS

We retrospectively analyzed a hospital-based sample of 967 patients with T2DM discharged from our Division of Endocrinology over the years 2007-2014. Standard electrocardiograms were performed on all patients and were interpreted by expert cardiologists.

RESULTS

Overall, 267 (27.6%) patients had some type of conduction defects on electrocardiograms (defined as at least one block among first-degree atrio-ventricular block, second-degree block, third-degree block, left bundle branch block, right bundle branch block, left anterior hemi-block or left posterior hemi-block). Patients in the 3rd serum uric acid tertile had a higher prevalence of any cardiac conduction defects than those belonging to 2nd or 1st tertile, respectively (35.8% vs. 25.0% vs. 22.6%; p<0.0001). Elevated serum uric acid levels were associated with a nearly twofold increased risk of cardiac conduction defects after adjustment for age, sex, hemoglobin A1c, diabetes duration, metabolic syndrome, chronic kidney disease, chronic obstructive pulmonary disease, ischemic heart disease, valvular heart disease and medication use (adjusted-odds ratio 1.84, 95% confidence intervals 1.2-2.9; p=0.009).

CONCLUSIONS

Moderately elevated serum uric acid levels are associated with an increased prevalence of any cardiac conduction defects in hospitalized patients with T2DM, independent of multiple risk factors and potential confounding variables.

A user-friendly risk-score for predicting in-hospital cardiac arrest among patients admitted with suspected non ST-elevation acute coronary syndrome - The SAFER-score

AIM

To develop a simple risk-score model for predicting in-hospital cardiac arrest (CA) among patients hospitalized with suspected non-ST elevation acute coronary syndrome (NSTE-ACS).

METHODS

Using the Swedish Web-system for Enhancement and Development of Evidence-based care in Heart disease Evaluated According to Recommended Therapies (SWEDEHEART), we identified patients (n=242 303) admitted with suspected NSTE-ACS between 2008 and 2014. Logistic regression was used to assess the association between 26 candidate variables and in-hospital CA. A risk-score model was developed and validated using a temporal cohort (n=126 073) comprising patients from SWEDEHEART between 2005 and 2007 and an external cohort (n=276 109) comprising patients from the Myocardial Ischaemia National Audit Project (MINAP) between 2008 and 2013.

RESULTS

The incidence of in-hospital CA for NSTE-ACS and non-ACS was lower in the SWEDEHEART-derivation cohort than in MINAP (1.3% and 0.5% vs. 2.3% and 2.3%). A seven point, five variable risk score (age ≥60 years (1 point), ST-T abnormalities (2 points), Killip Class >1 (1 point), heart rate <50 or ≥100bpm (1 point), and systolic blood pressure <100mmHg (2 points) was developed. Model discrimination was good in the derivation cohort (c-statistic 0.72) and temporal validation cohort (c-statistic 0.74), and calibration was reasonable with a tendency towards overestimation of risk with a higher sum of score points. External validation showed moderate discrimination (c-statistic 0.65) and calibration showed a general underestimation of predicted risk.

CONCLUSIONS

A simple points score containing five variables readily available on admission predicts in-hospital CA for patients with suspected NSTE-ACS.

Nonalcoholic fatty liver disease is associated with an increased risk of heart block in hospitalized patients with type 2 diabetes mellitus

Recent studies suggested that nonalcoholic fatty liver disease (NAFLD) is associated with an increased risk of cardiac tachyarrhythmias (mainly atrial fibrillation) in patients with and without type 2 diabetes mellitus. The aim of this study was to examine whether an association also exists between NAFLD and heart block. We have retrospectively evaluated a hospital-based cohort of 751 patients with type 2 diabetes discharged from our Division of Diabetes and Endocrinology during years 2007–2014. Standard electrocardiograms were performed on all patients. Diagnosis of NAFLD was based on ultrasonography, whereas the severity of advanced hepatic fibrosis was based on the fibrosis (FIB)-4 score and other non-invasive fibrosis markers. Overall, 524 (69.8%) patients had NAFLD and 202 (26.9%) had heart block (defined as at least one block among first-degree atrio-ventricular block, second-degree block, third-degree block, left bundle branch block, right bundle branch block, left anterior hemi-block or left posterior hemi-block) on electrocardiograms. Patients with NAFLD had a remarkably higher prevalence of any persistent heart block than those without NAFLD (31.3% vs. 16.7%, p<0.001); this prevalence was particularly increased among those with higher FIB-4 score. NAFLD was associated with a threefold increased risk of prevalent heart block (adjusted-odds ratio 3.04, 95% CI 1.81–5.10), independently of age, sex, hypertension, prior ischemic heart disease, hemoglobin A1c, microvascular complication status, use of medications and other potentially confounding factors. In conclusion, this is the largest cross-sectional study to show that NAFLD and its severity are independently associated with an increased risk of prevalent heart block in hospitalized patients with type 2 diabetes.

Nonalcoholic Fatty Liver Disease (NAFLD) and Risk of Cardiac Arrhythmias: A New Aspect of the Liver-heart Axis

Nonalcoholic fatty liver disease (NAFLD) is a pathologic condition frequently observed in clinical practice. To date, the prevalence of NAFLD is approximately 25-30% among adults of the general population in Western countries but increases to approximately 70-75% among patients with type 2 diabetes mellitus. In the last decade, accumulating evidence has clearly demonstrated that patients with NAFLD have not only an increased liver-related morbidity and mortality but also an increased risk of fatal and non-fatal cardiovascular events. In particular, several studies have documented the existence of an independent association among NAFLD and cardiac changes in structure and function in both non-diabetic and diabetic patients. In addition, mounting evidence also suggests that there is a strong relationship between NAFLD and cardiac arrhythmias, such as atrial fibrillation, QTc prolongation and ventricular arrhythmias. This is of clinical interest, as it could explain, at least in part, the increased risk of death for cardiovascular disease in patients with NAFLD. Therefore, seeing that cardiovascular disease complications are the leading cause of disability and death in NAFLD patients, the recent European clinical practice guidelines advised to check the cardiovascular system in all patients with NAFLD. This clinical mini review will briefly describe the increasing body of evidence regarding the association between NAFLD and cardiac arrhythmias, and discuss the potential biological mechanisms underlying this association.

Complete atrioventricular block in acute coronary syndrome: prevalence, characterisation and implication on outcome

PURPOSE

The aim was to characterise acute coronary syndrome patients with complete atrioventricular block and to assess the effect on outcome.

METHODS

Patients admitted with acute coronary syndrome were divided according to the presence of complete atrioventricular block: group 1, with complete atrioventricular block; group 2, without complete atrioventricular block. Clinical, electrocardiographic and echocardiographic characteristics and prognosis during one year follow-up were compared between the groups.

RESULTS

Among 4799 acute coronary syndrome patients admitted during the study period, 91 (1.9%) presented with complete atrioventricular block. At presentation, group 1 patients presented with lower systolic blood pressure, higher Killip class and incidence of syncope. In group 1, 86.8% presented with ST-segment elevation myocardial infarction (STEMI), and inferior STEMI was verified in 79.1% of patients in group 1 compared with 21.9% in group 2 ( P<0.001). Right ventricular myocardial infarction was more frequent in group 1 (3.3% vs. 0.2%; P<0.001). Among patients who underwent fibrinolysis complete atrioventricular block was observed in 7.3% in contrast to 2.5% in patients submitted to primary percutaneous coronary intervention ( P<0.001). During hospitalisation group 1 had worse outcomes, with a higher incidence of cardiogenic shock (33.0% vs. 4.5%; P<0.001), ventricular arrhythmias (17.6% vs. 3.6%; P<0.001) and the need for invasive mechanical ventilation (25.3% vs. 5.1%; P<0.001). After a propensity score analysis, in a multivariate regression model, complete atrioventricular block was an independent predictor of hospital mortality (odds ratio 3.671; P=0.045). There was no significant difference in mortality at one-year follow-up between the study groups.

CONCLUSION

Complete atrioventricular block conferred a worse outcome during hospitalisation, including a higher incidence of cardiogenic shock, ventricular arrhythmias and death.