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Long-term survival of patients with incomplete bundle-branch block complicating acute myocardial infarction
Insights
Patients with incomplete bilateral bundle-branch block after myocardial infarction can survive long-term. Survivors often had a normal HV interval or a transient block that resolved.
Area of Science:
- Cardiology
- Electrophysiology
- Internal Medicine
Background:
- Incomplete bilateral bundle-branch block is a complication of acute myocardial infarction.
- Prognostic indicators for patients with this condition require further elucidation.
Purpose of the Study:
- To investigate the long-term survival and prognostic factors in patients with incomplete bilateral bundle-branch block following acute myocardial infarction.
Main Methods:
- Review of electrocardiograms and His bundle electrograms in 28 patients.
- Analysis of HV interval duration and changes over time.
- Comparison of survival rates based on baseline HV interval and block resolution.
Main Results:
- Patients with an abnormal HV interval (≥55 ms) had a higher mortality rate (65%) compared to those with a normal HV interval (20%), though not statistically significant.
- Disappearance of the incomplete bilateral bundle-branch block was significantly more frequent in survivors (7/12) than non-survivors (2/16) (P < 0.05).
- Four of 6 survivors with an initially abnormal HV interval showed a decrease of 10-15 ms on sequential His bundle electrograms.
Conclusions:
- Long-term survival is achievable in patients with incomplete bilateral bundle-branch block complicating acute myocardial infarction.
- Favorable prognostic indicators include an initially normal HV interval, transient incomplete bilateral bundle-branch block, and a decreasing HV interval if initially abnormal.
Abstract:
Electrocardiograms and His bundle electrograms were reviewed in 28 patients with incomplete bilateral bundle-branch block complicating acute myocardial infarction. All had a His bundle electrogram at the time of pacemaker insertion; 10 had a second one. Of 23 patients with an initially abnormal HV interval (55 ms or greater), 15 died (65%), while only one died (20%) in the group of 5 with a normal HV interval. This difference is not statistically significant. Sequential His bundle electrograms were done in 6 of the 8 survivors with an initially abnormal HV interval, and 4 showed 10 to 15 ms decrease in HV interval. The disappearance of incomplete bilateral bundle-branch block occurred significantly more often in patients who survived (7 of 12) when compared with those who did not survive (2 of 16) (P less than 0.05). It is concluded that long-term survival is po-sible after incomplete bilateral bundle-branch block complicating acute myocardial infarction. The characteristics of the survivors include an initially normal HV interval, transient incomplete belateral bundle-branch block and a decreasing HV interval if it were initially abnormal.