While Multimodal Large Language Models (MLLMs) show promising performance in automated electrocardiogram interpretation, it remains unclear whether they genuinely perform actual step-by-step reasoning or just rely on superficial visual cues. To investigate this, we introduce ECG-Reasoning-Benchmark, a… See the full description on the dataset page: https://huggingface.co/datasets/Jwoo5/ECG-Reasoning-Benchmark.