Electromechanical mapping of the left ventricle for stem cell injection in a patient with permanent atrial fibrillation
Bibliographic record
Abstract
Stem cell therapies for improvement of the ischaemic myocardium are an emerging and promising therapeutic option. Three-dimensional NOGA mapping allows simultaneous registration of left ventricle (LV) mechanical and electrical activity, enabling assessment of myocardial viability and targeted cell delivery. However, LV mapping in patients during atrial fibrillation (AF) is considered time consuming and difficult. A 77-year-old man was admitted to our centre presenting with refractory angina. His risk factors included hypertension, hyperlipidaemia, and advanced chronic renal failure, he also had a history of permanent AF. In the past he had undergone coronary artery bypass grafting twice: in 1985 and 2002, he had also suffered from a non-ST-elevation myocardial infarction treated with percutaneous coronary intervention with a drug eluting stent implantation in 2010. At the moment of admission, he was in CCS class III despite optimal medical treatment. The patient had previously been disqualified from any further revascularisation by the Heart Team. Echocardiography revealed a mild impairment of the LV ejection fraction (LVEF 45%), with hypokinesia of the intraventricular septum and inferior wall. Single-photon emission computed tomography (SPECT) showed reversible perfusion defects in the anterolateral region. AF with short QRS duration (80 ms) and relatively good rate control (80 bpm) was observed in an electrocardiogram. The patient was enrolled to the REGENT (autologous CD133+ cells vs. placebo, double-blind, placebo-controlled RCT) trial to undergo targeted transendocardial treatment. We used a NOGA-XP System to perform electromechanical mapping and direct transendocardial cell injection. A diagnostic NOGA STAR catheter was placed in the LV under fluoroscopic guidance, and LV electromechanical mapping was performed. Completing the data necessary to build the map and localise the target area took about 60 min. The regions of hibernating myocardium defined by preserved electrical and decreased mechanical activity correlated with reversible perfusion defects detected by SPECT. Time volume graphs showed evident dyssynchrony of the hibernating areas (Fig. 1). Following the standardised NOGA injection criteria, twelve 0.2 mL injections of autologous CD133+ bone marrow stem cells or placebo (procedure double-blinded) were placed into the anterolateral viable area (> 5 mV unipolar) with low wall movement (< 6% LLS) (Fig. 2). Only limited premature ventricular contractions were detectable at injections, which can probably be explained by a reduced time window for excitation after the electrical refractory period. Total injection time was 20 min. Mapping and injection were completed within 80 min despite permanent AF. No raise in creatinine levels, pericardial effusion, and no local complications were observed in the days following the procedure. To conclude, despite technical difficulties due to irregular rhythm, electromechanical mapping on AF is feasible. Completing the procedure in patients with AF and good heart rate control does not have to be more time consuming than in patients on sinus rhythm. Additionally, time volume graphs display differences in wall movement of hibernating and normal tissue even during AF, providing us with additional information on segmental ventricular contraction synchrony.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
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 teacher head, 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".