Thirty-year trends (1975-2005) in the magnitude and hospital death rates associated with complete heart block in patients with acute myocardial infarction: a population-based perspective

Prognostic Implications of High-Degree Atrio-Ventricular Block in Patients with Acute Myocardial Infarction in the Contemporary Era

BACKGROUND

High-degree atrioventricular block (HAVB) is a known complication of ST-segment elevation myocardial infarction (STEMI). We aimed to determine the prevalence and prognostic impact of HAVB in a contemporary cohort of STEMI.

METHODS

Data were collected from the DIAMANTE registry that included STEMI patients admitted to our cardiac intensive care unit treated with urgent reperfusion. We studied the clinical characteristics and evolution in patients with and without HAVB at admission.

RESULTS

From 1109 consecutive patients, HAVB was documented in 95 (8.6%). The right coronary artery was the culprit vessel in 84 patients with HAVB (88.4%). The independent predictors of HAVB were: male sex (OR 1.9, 95% CI 1.2-2.9), age (OR 1.03, 95% CI 1.01-1.05), involvement of right coronary artery (OR 12.4, 95% CI 7.6-20.2), and creatinine value (OR 1.5, 95% CI 1.1-2.0). A transient percutaneous pacemaker was used in 37 patients with HAVB (38.9%). Patients with HAVB had higher mortality that patients without HAVB (15.8% vs. 4.1%, p < 0.001); however, in multivariate analysis, HAVB was not an independent predictor of in-hospital mortality.

CONCLUSIONS

HAVB was seen in 9% of STEMI patients and was particularly frequent in elderly males with renal failure. Patients with HAVB had a poor prognosis during hospitalization, but HAVB was not an independent predictor of in-hospital mortality.

Prognostic Value of Temporary Pacemaker Insertion in Patients with Acute Myocardial Infarction in the Era of Percutaneous Coronary Revascularization

Background

Patients with acute myocardial infarction (AMI) complicated with arrhythmia are not uncommon. Insertion of temporary pacemakers (tPMs) in patients with arrythmia during acute myocardial infarction (AMI) is imperative support therapy. Arrhythmias include high-degree atrioventricular block (AVB), sinus arrest/bradycardia, and ventricular arrythmia storm. To date, no study has evaluated the prognosis of tPMs in patients with AMI complicated with arrhythmia. Especially in the era of thrombolysis or emergency percutaneous coronary intervention (PCI) for coronary artery revascularization, our study was designed to investigate the value of tPMs implantation in cases of AMI complicated with various arrhythmias.

Methods

From January 2009 to January 2019, 35,394 patients with AMI, including 62.0% (21,935) with ST-segment elevation myocardial infarction (STEMI) and 38.0% (13,459) with non-ST-segment elevation myocardial infarction (NSTEMI) in four hospitals, were reviewed. A total of 552 patients with AMI associated with arrythmia were included in the cohort. Among the 552 patients, there were 139 patients with tPM insertions. The incidence trend of myocardial infarction complicated with various arrhythmias in the past 10 years was analysed, and the clinical characteristics, in-hospital mortality, postdischarge mortality, composite endpoints of modality, and independent risk factors were compared in patients with and without tPM in the era of coronary artery revascularization.

Results

In patients with AMI-associated arrythmia, high-degree AVB was the major cause of tPM insertion (p = 0.045). In the past 10 years, the number of patients with high-degree AVB, tPM implantation, ventricular arrythmia storm, and in-hospital mortality has decreased year by year in the era of coronary artery revascularization. In the tPM group, the culprit vessel was the left main artery, and cardiogenic shock, acute renal injury and high brain natriuretic peptide (BNP) levels were independent risk factors for patients with AMI complicated with arrhythmia. The in-hospital mortality in the tPM group was higher than that in the non-tPM group. The patients with tPM insertion showed better postdischarge survival than patients without tPM insertion.

Conclusions

In the era of emergency thrombolysis or PCI, coronary revascularization can ameliorate the prognosis of patients with AMI complicated with various arrhythmias. Temporary pacemaker insertion in patients with AMI complicated with arrhythmia can reduce the postdischarge mortality of these patients.

Factors associated with temporary pacing insertion in patients with inferior ST-segment elevation myocardial infarction

Background

High-degree atrioventricular block (HAVB) is a prognostic factor for survival in patients with inferior ST-segment elevation myocardial infarction (STEMI). However, there is little information about factors associated with temporary pacing (TP). The aim of this study was to find factors associated with TP in patients with inferior STEMI.

Methods

We included 232 inferior STEMI patients, and divided those into the TP group (n = 46) and the non-TP group (n = 186). Factors associated with TP were retrospectively investigated using multivariate logistic regression model.

Results

The incidence of right ventricular (RV) infarction was significantly higher in the TP group (19.6%) than in the non-TP group (7.5%) (p = 0.024), but the incidence of in-hospital death was similar between the 2 groups (4.3% vs. 4.8%, p = 1.000). Long-term major adverse cardiovascular events (MACE), which were defined as a composite of all-cause death, non-fatal myocardial infarction (MI), target vessel revascularization (TVR) and readmission for heart failure, were not different between the 2 groups (p = 0.100). In the multivariate logistic regression analysis, statin at admission [odds ratio (OR) 0.230, 95% confidence interval (CI) 0.062–0.860, p = 0.029], HAVB at admission (OR 9.950, 95% CI 4.099–24.152, p<0.001), and TIMI-thrombus grade ≥3 (OR 10.762, 95% CI 1.385–83.635, p = 0.023) were significantly associated with TP.

Conclusion

Statin at admission, HAVB at admission, and TIMI-thrombus grade ≥3 were associated with TP in patients with inferior STEMI. Although the patients with TP had the higher incidence of RV infarction, the incidence of in-hospital death and long-term MACE was not different between patients with TP and those without.

Transient complete atrioventricular block and ST-segment elevation induced by coronary vasospasm due to iatrogenic hyperkalemia: a case report

Background

Hyperkalemia and acute coronary syndrome are not only all responsible for syncope related to complete atrioventricular block, but also share parts of electrocardiogram manifestations. Additionally, they influence each other.

Case presentation

A 32-year-old Chinese man presented with severe hypokalemia (1.63 mmol/l) at midnight in the emergency room. He developed unexpected rebound hyperkalemia (7.76 mmol/l) after 18 hours of oral and intravenous potassium chloride supplementation at a concentration of about 10 g/day and a rate of 10 mmol/hour. Subsequently, the patient complained of chest discomfort and dyspnea, followed by syncope for several minutes, approximately 2 hours after potassium reduction treatment had been started. The instant electrocardiogram showed complete atrioventricular block and elevated ST segment in the inferolateral leads, which resolved 15 minutes later, before hyperkalemia was corrected. Combined with mild coronary stenosis and negative myocardial injury markers, transient complete atrioventricular block induced by coronary vasospasm due to iatrogenic hyperkalemia was diagnosed. Normal urine potassium excretion, acid–base state, and other examinations made the diagnosis of hypokalemic periodic paralysis possible.

Conclusions

Hyperkalemia may provoke acute coronary syndrome, and early coronary angiography is an effective strategy for identifying the direct cause of acute complete atrioventricular block.

Cardiogenic Shock Induced by Anterior Pituitary Hypofunction and Thyrotoxicosis

Cardiogenic shock occurs when the heart is unable to pump enough blood for the needs of the body. Hypopituitarism is a condition in which the pituitary gland does not produce enough of one or more hormones, and it rarely occurs with thyrotoxicosis. We report a rare case of cardiogenic shock induced by anterior pituitary hypofunction and thyrotoxicosis. A 47-year-old woman was admitted twice to the hospital due to generalized worsening muscle pain for 13 days, and accompanied by a transient loss of consciousness. Cardiogenic shock developed during hospitalization, which improved with active resuscitative measures. Laboratory tests showed thyrotoxicosis. Pituitary magnetic resonance imaging (MRI) and relevant hormone tests confirmed anterior pituitary hypofunction. The patient was given hormone replacement therapy, which stabilized her condition. We believe cardiogenic shock may be a serious complication of hypopituitarism. We recommend establishing an expert system (ES) to facilitate the early diagnosis and treatment of cardiogenic shock, improve the professional skills of primary care physicians, and optimize treatment plans.

The time to reversal of complete atrioventricular block and its predictors in acute ST-segment elevation myocardial infarction

OBJECTIVE

The purpose of this study was to determine the time to reversal of complete AV block (CAVB) in ST-segment elevation myocardial infarction (STEMI) with various modalities of treatment and to examine the factors associated with early reversal of CAVB.

METHODS

We prospectively assessed the STEMI patients complicated by CAVB. The mean time to reversal of CAVB was analyzed and compared according to the treatment received. Multivariate logistic regression analysis was performed to find the predictors of mortality.

RESULTS

Of 3954 patients with STEMI, CAVB was present in 146(3.7%) patients. Inferior wall myocardial infarction (IWMI) was more commonly associated with CAVB than anterior wall myocardial infarction (AWMI) (74.7% vs 25.3%). The mean time to reversal of CAVB was 25.4 ± 35.5 h. It was significantly lower with the primary percutaneous coronary intervention (PCI) compared to thrombolysis (5.21 ± 10.54 vs 12.98 ± 17.14; p = 0.0001). Predictors of early reversal of CAVB were early presentation to hospital (<6 h) from symptom onset, presence of IWMI, any revascularization done, primary PCI performed in comparison to thrombolysis, and normal serum creatinine levels. The presence of older age, broader QRS complex, cardiogenic shock/heart failure, and elevated creatinine were independent predictors of mortality. The CAVB reverted in all the alive patients except one who required permanent pacemaker implantation.

CONCLUSION

CAVB is uncommon in STEMI and it recovers in a vast majority of surviving patients. The time to reversal of CAVB in STEMI is lower with primary PCI compared to thrombolysis. Outcomes are poor without revascularization in such patients.

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.

Bundle branch blocks and/or hemiblocks complicating acute myocardial ischemia or infarction

Despite the bulk of anatomical and histologic evidence supporting the existence of three fascicules in the left branch of the His bundle, the concept of a bifascicular system proposed by Rosenbaum and his school has been adopted by the cardiological community as a practical teaching tool. Left anterior hemiblock (LAH) refers to block of the antero-superior branch of the left branch which is small and left posterior hemiblock (LPH) to block of the postero-inferior branch which is larger. The LAH is more common that the LPH and often associated with a complete right bundle branch block (RBBB). Coronary artery disease (CAD) is a major cause of hemiblocks. In this review article, we discuss various aspects of the relation of hemiblocks with CAD. We looked at the prevalence of LAH in consecutive patients undergoing coronary angiography and who had a significant coronary lesion in one vessel or more. In all patients with LAH, a significant lesion of the left anterior descending coronary artery was present, with in the majority of patients, an impairment of the left ventricular function. Bifascicular block (RBBB with LAH or LPH) can complicate acute myocardial infarction and is often associated with a poor prognosis and the presence of heart failure. Thrombolysis and or early angioplasty in acute myocardial infarction have significantly improved the prognosis and reduced the mortality associated with bifascicular block. Left anterior hemiblock pattern was also observed during angina pectoris occurring at rest or induced by exercise or atrial pacing. In these circumstances, LAH is transient and is likely to be due to ischemia in the anterolateral wall related to a lesion of the main trunk or the proximal left anterior descending coronary artery with the postero-inferior wall being first depolarized. The presence of bifascicular block in acute myocardial infarction still is associated with an unfavorable prognosis as compared to non-bundle branch block patients because of the common association with heart failure and other comorbidities.

Clinical outcomes according to symptom presentation in patients with acute myocardial infarction: Results from the FAST-MI 2010 registry

BACKGROUND

Atypical clinical presentation in acute myocardial infarction (AMI) patients is not uncommon; most studies suggest that it is associated with unfavorable prognosis.

HYPOTHESIS

Long-term clinical impact differs according to predominant symptom presentation (typical chest pain, atypical chest pain, syncope, cardiac arrest, or dyspnea) in AMI patients.

METHODS

FAST-MI 2010, a nationwide French registry, included 4169 patients with AMI in 213 centers at the end of 2010 (76% of active centers). Demographics, medical history, hospital management, and outcomes were compared according to predominant symptom presentation.

RESULTS

Typical chest pain with no other symptom was reported in 3020 patients (68% in STEMI patients, 76% in NSTEMI patients). Atypical chest pain, dyspnea, syncope, and cardiac arrest were reported in 11%, 11%, 5%, and 1%, respectively. Patients with atypical clinical presentation had a higher cardiovascular risk profile and received fewer medications and a less invasive strategy. Using Cox multivariate analysis, atypical chest pain was not associated with higher death rate at 3 years (HR: 0.96, 95% CI: 0.69-1.33, P = 0.78), whereas cardiac arrest (HR: 2.44, 95% CI: 1.00-5.97, P = 0.05), syncope (HR: 1.70, 95% CI: 1.18-2.46, P = 0.005), and dyspnea (HR: 1.66, 95% CI: 1.31-2.10, P < 0.001) were associated with higher long-term mortality compared with patients with typical isolated chest pain. Similar trends were observed in STEMI and NSTEMI populations.

CONCLUSIONS

Atypical clinical presentation is observed in about 20% of AMI patients. Cardiac arrest, dyspnea, and syncope represent independent predictors of long-term mortality in STEMI and NSTEMI populations.

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.

Clinical Characteristics and Outcomes of Patients with Ischemic and Non-Ischemic Complete Heart Block

INTRODUCTION

Third degree or complete heart block (CHB) is a medical emergency and usually requires permanent pacemaker placement. CHB can be caused by cardiac ischemia or non-ischemic conditions such as infiltrative diseases or fibrosis. The purpose of this study is to identify the baseline clinical characteristics associated with ischemic versus non-ischemic causes of complete heart block and compare their outcomes.

MATERIALS AND METHODS

An institutional review broad approval was granted by the Cleveland Clinic Health System. In our study, 216 patients with CHB presenting to Fairview Hospital between January 2014 and June 2016 were initially identified using the International Classification of Disease (ICD) codes at discharge. Only the patients with a new diagnosis of complete heart block (CHB) were included in the study (total N=62), which led to the exclusion of 154 patients. The patients were characterized into non-ischemic and ischemic groups based on cardiac marker elevation, electrocardiogram changes and/or cardiac catheterization findings. In all the patients, data including the following was collected: demographics such as age, gender, ethnicity and body mass index; pre-existing comorbidities such as hypertension, chronic kidney disease, diabetes mellitus, thyroid disease, previous coronary artery disease, history of cancer; use of nodal blocking agents, electrolyte abnormalities on admission, echocardiographic parameters such as ejection fraction (EF), right ventricular systolic pressure (RVSP), left ventricular end diastolic and systolic volumes (LVEDV and LVESV, respectively). The primary outcome was all-cause mortality and the secondary outcome was pacemaker placement. Categorical variables were analyzed using chi-square and continuous variables using ANOVA.

RESULTS

Out of 62 patients (N=62), 48 had non-ischemic and 14 had ischemic CHB. The mean age was 67 years (95% CI, 60.55-74.73) in the ischemic group and 75 years (95% CI, 71.52-78.80) in the non-ischemic group, p=0.04. Patients with ischemic CHB had a lower mean EF of 49.6% (95% CI, 42.04%-57.23%) compared to 57.42% in non-ischemic CHB patients (95% CI, 53.97%-60.87%), p=0.05. History of coronary artery disease was present in 71.4% (10/14) patients with ischemic CHB compared to 37.5% (18/48) patients with non-ischemic CHB, p=0.02. There was no statistically significant difference between the two groups in terms of gender, diabetes, hypertension, thyroid dysfunction, chronic kidney disease, nodal blocking agents, electrolyte abnormalities or smoking status. For outcomes, 6/48 (12.5%) of patients with non-ischemic CHB had died compared to 3/14 (21.4%) ischemic CHB (p=0.327). Permanent pacemaker was implanted in 45/48 patients (93.75%) of the non-ischemic CHB compared to 6/14 (42.83%) in the ischemic group (p<0.001).

CONCLUSIONS

Patients with ischemic CHB are younger, and they have a lower ejection fraction but they are less likely to get a pacemaker compared to non-ischemic CHB. Further studies with a bigger sample size are required to understand the long term mortality outcomes of patients with CHB.

Incidence, Predictors, and Outcomes of High-Grade Atrioventricular Block in Patients With ST-Segment Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention (from the HORIZONS-AMI Trial)

High-grade atrioventricular block (HAVB) is historically considered a marker of worse outcomes in patients with ST-segment elevation myocardial infarction (STEMI). However, the predictors and prognostic impact of HAVB in the primary percutaneous coronary intervention (PCI) era remain poorly understood. We sought to describe the characteristics and predictors of HAVB in patients undergoing primary PCI in STEMI and to assess the prognostic significance of HAVB in the contemporary reperfusion era. The present analysis includes 3,115 patients presenting with STEMI from the Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction trial who underwent primary PCI. Outcomes were examined according to the presence of HAVB on a presenting electrocardiogram, as interpreted by an independent electrocardiography core laboratory. HAVB (second-degree Mobitz II or third-degree atrioventricular block) was present at baseline in 46 patients (1.5%). Independent predictors of HAVB included increased age, diabetes mellitus, right coronary artery occlusion, sum of ST-segment deviation, and baseline Thrombolysis In Myocardial Infarction flow 0/1. Thrombolysis In Myocardial Infarction flow 3 was restored in 83.7% and 91.5% of patients with versus without baseline HAVB respectively (p = 0.06). Mortality rate was significantly higher in patients with versus without HAVB at 30-day, 1-, and 3-year follow-ups (unadjusted hazard ratio [HR] 3.83, 95% CI 1.40 to 10.48; unadjusted HR 4.37, 95% CI 2.09 to 9.38 and unadjusted HR 2.78, 95% CI 1.31 to 5.91, respectively). After covariate adjustment, mortality rate was significantly higher in patients with HAVB at 1 year (adjusted HR 2.45, 95% CI 1.09 to 5.50, p = 0.03) but not at 30 days (adjusted HR 1.70, 95% CI 0.58 to 5.01, p = 0.33) or 3 years (adjusted HR 0.71 to 3.41, p = 0.27). In conclusion, HAVB is a rare complication of STEMI but remains associated with increased mortality, even after primary PCI.

Periprocedural temporary pacing in primary percutaneous coronary intervention for patients with acute inferior myocardial infarction

OBJECTIVE

High-degree atrioventricular block (AVB), including complete AVB in acute inferior ST-elevation myocardial infarction (STEMI), is not uncommon. However, there is no study evaluating the clinical differences between patients who have undergone temporary pacing (TP) and patients who have not. The present study was designed to investigate whether TP has any prognostic significance in inferior STEMI complicated by complete AVB.

METHODS

From January 2009 to December 2014, 295 consecutive patients diagnosed with inferior wall STEMI in a university hospital were reviewed. All of them underwent primary percutaneous coronary intervention (PCI). Among the 295 patients, there were 72 patients with complete AVB. The clinical characteristics, procedural data, and long-term major adverse cardiocerebrovascular events were compared in patients with and without TP.

RESULTS

Baseline clinical and procedural characteristics were similar between patients with and without TP. Patients with TP were more likely to present with cardiogenic shock; thus, additional interventions were attempted via a femoral approach, as patients received further treatment with intra-aortic balloon pumps and were subjected to additional cardiopulmonary resuscitation. Most cases of complete AVB were primarily caused by right coronary artery occlusion. After a median follow-up period of 344 (range, 105.5-641) days, major adverse cardiocerebrovascular events did not differ between the groups (P=0.528).

CONCLUSION

We conclude that primary PCI without TP is acceptable in complete AVB-complicated acute inferior STEMI. To avoid delay in reperfusion, we suggest that primary PCI should be the first priority therapy rather than treating patients initially with TP.

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

Non-ST-segment myocardial infarction (NSTEMI) can be complicated by high-degree atrioventricular (AV) block, asystole, or electromechanical dissociation (EMD), but these events are not well characterized in the contemporary era. This analysis assesses the incidence of and factors associated with these dysrhythmias in acute NSTEMIs.

METHODS

Patients with NSTEMI in the EARLY ACS, PLATO, and TRACER trials were included in the pooled cohort (N = 29,677). Logistic regression was used to identify factors associated with in-hospital high-degree AV block and asystole or EMD, and Kaplan-Meier methods were used to assess mortality.

RESULTS

High-degree AV block occurred in 112 (0.4%) patients, asystole in 157 (0.5%), and EMD in 38 (0.1%). Pacemakers were inserted in 241 patients (0.8%) during the index hospitalization: 30 (12%) for AV block. Among patients with high-degree AV block, we observed more frequent right coronary artery lesions (47% vs 29%). Age, diabetes, lower heart rate, and lower blood pressure were associated with high-degree AV block. Higher Killip class, ST-segment depression, prior myocardial infarction, and peripheral vascular disease were most strongly associated with asystole or EMD. Ten-day unadjusted survival was 90% for patients with high-degree AV block and 43% for those with asystole or EMD.

CONCLUSIONS

Although high-degree AV block, asystole, and EMD were infrequent complications of NSTEMI, they were associated with substantial short-term mortality. Only 1 in 8 pacemakers placed in NSTEMI patients during the acute hospitalization was for high-degree AV block.

Influence of second- and third-degree heart block on 30-day outcome following acute myocardial infarction in the drug-eluting stent era

This study was conducted to investigate the prognostic value of heart block among patients with acute myocardial infarction (AMI) treated with drug-eluting stents. A total of 13,862 patients with AMI, registered in the nation-wide AMI database from January 2005 to June 2013, were analyzed. Second- (Mobitz type I or II) and third-degree atrioventricular block were considered as heart block in this study. Thirty-day major adverse cardiac events (MACE) including all causes of death, recurrent myocardial infarction, and revascularization were evaluated. Percutaneous coronary intervention with implantation of drug-eluting stent was performed in 89.8% of the patients. Heart block occurred in 378 patients (2.7%). Thirty-day MACE occurred in 1,144 patients (8.2%). Patients with heart block showed worse clinical parameters at initial admission, and the presence of heart block was associated with 30-day MACE in univariate analyses. However, the prognostic impact of heart block was not significant after adjustment of potential confounders (p = 0.489). Among patients with heart block, patients with a culprit in the left anterior descending (LAD) coronary artery had worse clinical outcomes than those of patients with a culprit in the left circumflex or right coronary artery. LAD culprit was a significant risk factor for 30-day MACE even after controlling for confounders (odds ratio 5.28, 95% confidence interval 1.22 to 22.81, p = 0.026). In conclusion, despite differences in clinical parameters at the initial admission, heart block was not an independent risk factor for 30-day MACE in adjusted analyses. However, a LAD culprit was an independent risk factor for 30-day MACE among patients with heart block.

Clinical significance of late high-degree atrioventricular block in patients with left ventricular dysfunction after an acute myocardial infarction--a Cardiac Arrhythmias and Risk Stratification After Acute Myocardial Infarction (CARISMA) substudy

BACKGROUND

High-degree atrioventricular block (HAVB) is a frequent complication in the acute stages of a myocardial infarction associated with an increased rate of mortality. However, the incidence and clinical significance of HAVB in late convalescent phases of an AMI is largely unknown. The aim of this study was to assess the incidence and prognostic value of late HAVB documented by continuous electrocardiogram (ECG) monitoring in post-AMI patients with reduced left ventricular function.

METHODS

The study included 286 patients from the CARISMA study with AMI and left ventricular ejection fraction of 40% or less. An insertable loop recorder was implanted 5 to 21 days after AMI for incessant arrhythmia surveillance. Furthermore, ECG documentation was supplemented by a 24-hour Holter monitoring conducted at week 6 post-AMI. The clinical significance of HAVB occurring more than 21 days after AMI was examined with respect to development of major heart failure events and major ventricular tachyarrhythmic events.

RESULTS

During a median follow-up of 1.9 years (interquartile range 0.9-2.0), late HAVB was documented in 30 patients. The risk of major heart failure events (hazard ratio [HR] 4.08 [1.38-12.09], P = .01) and major ventricular tachyarrhythmic events (HR = 5.41 [1.88-15.58], P = .002) were significantly increased in patients who developed late HAVB.

CONCLUSION

High-degree atrioventricular block documented by continuous ECG monitoring occurring more than 3 weeks after AMI is a frequent complication in post-AMI patients with left ventricular dysfunction. Furthermore, HAVB is associated with ominous prognostic implications of both potentially lethal arrhythmias and heart failure.

Acute myocardial infarction hospitalization in the United States, 1979 to 2005

BACKGROUND

We reported earlier that there was no decline of acute myocardial infarction hospitalization from 1988 to 1997. We now extend these observations to document trends in acute myocardial infarction hospitalization rates and in-hospital case-fatality rates for 27 years from 1979 to 2005.

METHODS

We determined hospitalization rates for acute myocardial infarction by age and gender using data from the National Hospital Discharge Survey and US civilian population from 1979 to 2005, aggregated by 3-year groupings. We also assessed comorbid, complications, cardiac procedure use, and in-hospital case-fatality rates.

RESULTS

Age-adjusted hospitalization rate for acute myocardial infarction identified by primary International Classification of Diseases code was 215 per 100,000 people in 1979-1981 and increased to 342 in 1985-1987. Thereafter, the rate stabilized for the next decade and then declined slowly after 1996 to 242 in 2003-2005. Trends were similar for men and women, although rates for men were almost twice that of women. Hospitalization rates increased substantially with age and were the highest among those aged 85 years or more. Although median hospital stay decreased from 12 to 4 days, intensity of hospital care increased, including use of coronary angioplasty, coronary bypass, and thrombolytics therapy. During the period, reported comorbidity from diabetes and hypertension increased. Acute myocardial infarction complicated by heart failure increased, and cardiogenic shock decreased. Altogether, the in-hospital case-fatality rate declined.

CONCLUSION

During the past quarter century, hospitalization for acute myocardial infarction increased until the mid-1990s, but has declined since then. At the same time, in-hospital case-fatality rates declined steadily. This decline has been associated with more aggressive therapeutic intervention.