Related Experiment Videos
Advanced early and late atrioventricular block in acute inferior wall myocardial infarction
Insights
Patients with early-onset atrioventricular (AV) block during acute myocardial infarction (AMI) face higher risks of syncope, heart failure, and mortality. Late-onset AV block in AMI patients indicates a better prognosis and lower mortality risk.
Area of Science:
- Cardiology
- Electrophysiology
- Internal Medicine
Background:
- Acute myocardial infarction (AMI) can lead to atrioventricular (AV) block, a serious complication.
- The timing and characteristics of AV block in inferior AMI may influence patient outcomes.
Purpose of the Study:
- To investigate the differences in clinical presentation, management, and outcomes between early-onset and late-onset advanced AV block in patients with inferior AMI.
- To identify specific patient subgroups within inferior AMI with advanced AV block that contribute to high mortality rates.
Main Methods:
- Retrospective analysis of 76 patients with acute inferior AMI and advanced AV block.
- Classification of patients into 'early block' (during hyperacute ECG stage) and 'late block' (during subsequent ECG stages) groups.
- Comparison of ECG characteristics, response to atropine, need for pacemakers, morbidity (syncope, heart failure, cardiogenic shock), and mortality between the two groups.
Main Results:
- Early block group (31 patients) showed early, short-duration, third-degree block, poor atropine response, and higher pacemaker need.
- Late block group (45 patients) exhibited late, longer-duration, second-degree block, positive atropine response, and lower pacemaker need.
- Early block patients had significantly higher rates of syncope (32% vs 2%), left heart failure (36% vs 7%), and cardiogenic shock (39% vs 2%).
- Mortality was high in the early block group (23%) but low in the late block group (7%).
Conclusions:
- Early-onset advanced AV block in inferior AMI is associated with significantly increased morbidity and mortality.
- Late-onset advanced AV block in inferior AMI carries a better prognosis and lower mortality.
- Identifying early block as a high-risk subgroup is crucial for understanding and managing mortality in inferior AMI with AV block.
Abstract:
Seventy-six patients with acute inferior acute myocardial infarction (AMI) and advanced atrioventricular (AV) block are described. According to pre-established ECG criteria and time of appearance of the advanced AV block, patients were divided into two groups. The early block group consisted of 31 patients who developed advanced AV block during the hyperacute ECG stage of AMI. Advanced AV block in these patients was characterized by early appearance, short duration, third-degree type block, poor response to atropine, and increased need for pacemaker therapy. The late block group consisted of 45 patients who developed advanced AV block during subsequent ECG stages of AMI. Advanced AV block in these patients was characterized by late appearance, longer duration, second-degree type block, positive response to atropine, and diminished need for pacemaker therapy. Morbidity and mortality also differed between both groups. Patients with early block had more syncope (32% vs 2%, p less than 0.0001), more left heart failure (36 vs 7%, p less than 0.005), and more cardiogenic shock (39% vs 2%, p less than 0.001) than patients with late block. The mortality rate in the early block group was high (23%) and similar to that reported in the literature, whereas the mortality rate in the late block group was low (7%, p less than 0.05) and similar to the mortality rate reported for acute inferior AMI without advanced AV block. These data identify a subgroup of patients with acute inferior AMI and advanced AV block, which accounts for the high mortality rate reported in this group of patients.