Exercise-Induced Left Bundle Branch Block and Chest Pain in the Absence of Coronary Artery Disease: A Case Report and Review of the Literature
Bibliographic record
Abstract
Exercise-induced left bundle branch block (LBBB) is rare, but portends higher major cardiac events risk in the presence of coronary disease. It is more benign without coronary disease. We present a case of chest pain with exercise-induced LBBB with unusual features. A 59-year-old female was referred for evaluation of atypical chest pain. She was on medications for hypertension, dyslipidemia, and hypothyroidism. She denied tobacco or alcohol use. She underwent a Bruce protocol exercise treadmill test. Her resting heart rate was 76 beats per minute (BPM) and blood pressure was 150/85 mmHg. She was able to exercise for 8 min, achieving 9 METS. Her peak heart rate was 140 BPM without ischemic ST changes. At that heart rate, she developed LBBB, and complained of her usual chest discomfort. Her peak blood pressure was 209/83 mmHg. The test was terminated, and the patient was allowed to rest. Her rhythm continued to be LBBB for 2 min and 30 sec into recovery until, at a heart rate of 110 BPM, a premature ventricular contraction (PVC) resulted in resolution of LBBB. Shortly thereafter, her chest pain resolved. Subsequent cardiac catheterization revealed normal coronary arteries, ejection fraction (EF), and wall motion. Exercise-induced LBBB associated with chest pain may be a manifestation of underlying coronary disease and indicate poor prognosis. It renders the stress test uninterpretable and mandates its termination. However, certain clinical and electrocardiographic features may provide clues to non-ischemic etiology. J Med Cases • 2013;4(12):828-830 doi: http://dx.doi.org/10.4021/ jmc1576w
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.006 | 0.005 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.002 | 0.003 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.003 | 0.002 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".