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Right axis deviation in acute myocardial infarction. Clinical significance, hospital evolution, and long-term
Insights
Patients developing left posterior hemiblock during acute myocardial infarction face high morbidity and mortality. Right axis deviation indicates intermediate risk with increased cardiac symptoms, especially if persistent.
Area of Science:
- Cardiology
- Electrophysiology
Background:
- Acute myocardial infarction (AMI) can cause electrical conduction abnormalities.
- Rightward shift of the QRS axis is a recognized complication.
Purpose of the Study:
- To investigate the incidence, in-hospital course, and long-term outcomes of patients developing new rightward QRS axis deviation during AMI.
- To differentiate outcomes between left posterior hemiblock (LPHB) and right axis deviation (RAD) groups.
Main Methods:
- Retrospective analysis of 3,160 patients with AMI.
- Categorization into LPHB, RAD (incomplete LPHB), and control groups.
- Evaluation of in-hospital morbidity, mortality, and long-term cardiac symptomatology.
Main Results:
- LPHB developed in 0.41% and RAD in 1.8% of patients.
- The LPHB group had significantly higher in-hospital morbidity (69% congestive heart failure) and mortality (38.5%).
- The RAD group showed increased cardiac symptoms (angina, CHF) at follow-up, particularly if RAD persisted >24 hours.
Conclusions:
- LPHB during AMI identifies a high-risk population with substantial morbidity and mortality.
- RAD during AMI represents an intermediate risk group with a notable incidence of long-term cardiac symptoms.
Abstract:
The incidence, in-hospital evolution, and long-term follow-up were studied in patients who developed acute deviation of the mean (frontal) QRS axis to the right during an acute myocardial infarction (AMI). Among 3,160 patients evaluated, 13 (0.41 percent) developed left posterior hemiblock (LPHB) and 57 (1.8 percent) developed an incomplete form of LPHB, the right axis deviation group (RAD). Patients in the LPHB group had a statistically significant higher incidence of in-hospital morbidity (69 percent incidence of congestive heart failure) and mortality (38.5 percent). Follow-up revealed a statistically significant higher incidence of cardiac symptomatology (angina pectoris and congestive heart failure) in the RAD group than in the control group, mainly in patients in whom RAD persisted for more than 24 hours. Patients developing LPHB during AMI constitute a high risk population with a high incidence of morbidity and mortality. Patients developing RAD constitute an intermediate group (between the LPHB and the control group) characterized by a high incidence of cardiac symptoms at the time of follow-up.