While multimodal large language models (MLLMs) excel in medical applications, most of them favor static images or short-term signals. In the critical field of dynamic electrocardiograms (ECG), models struggle with complex temporal reasoning and diagnostic report generation due to a lack of high-quality datasets and benchmarks. To address this, we introduce (i) Holtercare-23K, a large-scale multimodal dynamic ECG dataset comprising 22,980 QA pairs derived from 788 clinical Holter records and featuring a novel signal-video-text tri-modal alignment. Based on this dataset, we present (ii) Holtercare-Bench, a multimodal benchmark that evaluates models on temporal localization, clinical diagnosis, and global summarization. Zero-shot evaluations of leading MLLMs reveal a significant performance gap in processing ultra-long pathological sequences. However, fine-tuning representative models yields substantial improvements. This work illuminates the limitations of current MLLMs in electrophysiology and provides a foundational benchmark for long-term medical MLLMs. Our project is available at https://github.com/ZJU4HealthCare/Holtercare-Bench.
Figures & tables
Figure 1. Overview of our proposed Holtercare-23K dataset.
Figure 2. The multimodal generation and data construction framework of HolterAgent.
Figure 3. Statistical distribution of Holtercare-23K. (a) Density estimation of recording durations. (b) Log-scale counts of beat-level annotations. (c) Frequencies of the top 10 rhythm-level events.
Figure 4. Zero-shot performance of four representative models across diverse metrics.
Figure 5. Performance comparison of Phi-4-mini-3.8B and Qwen3-VL-8B before and after fine-tuning. Metrics include Accuracy , Score MAE , and Score GPT . Tasks lacking these metrics are evaluated by F1-Bio .
Appendix figures & tables8 assets
Supplementary material from the paper’s appendix.
Appendix
Label
Description
Count
Valid QRS Complexes
N
Normal Beat
71,429,269
Af
Atrial Fibrillation
4,822,970
S
Atrial Premature Beat (APB)
1,042,095
P
Unclassified Pacing
840,298
V
Ventricular Premature Beat (VPB)
779,227
Appendix
Table 7. Frequency of beat-level annotations across Holtercare-23K.
Event
Count
Event
Count
Premature Atrial Contraction (PAC)
888
Sinus Arrest
6
Premature Ventricular Contraction (PVC)
775
Atrial Flutter (AFL)
6
PAC Couplets
396
Atrial Escape Rhythm
4
Atrial Tachycardia (AT)
339
Wandering Atrial Pacemaker (WAP)
4
PVC Couplets
152
Ventricular Escape Rhythm
3
Ventricular Tachycardia (VT)
94
Atrial Undersensing
2
Appendix
Table 8. Frequency of rhythm-level annotations across Holtercare-23K.
Figure 6. Prompt for QA pairs generation in Evidence Reasoning tasks of Open-QA .
Figure 7. Prompt for report evaluation in General Summary tasks of Report Generation .
Model
Modality
Event Timing
Diagnosis
Evidence Reasoning
BLEU-1 ↑
BLEU-4 ↑
BLEU-1 ↑
BLEU-4 ↑
BLEU-1 ↑
BLEU-4 ↑
Generalist Models
GPT-5-mini
37.50
10.83
8.70
1.96
96.67
38.48
Claude-4.5-Haiku
11.68
1.25
6.98
0.55
57.53
8.97
Phi-4-mini-3.8B
53.57
13.22
53.85
15.73
96.49
55.56
Phi-4-mini-3.8B FT
95.00
77.39
98.46
87.05
93.70
72.64
Appendix
Table 9. Supplementary performance comparison of evaluated models on Open-QA tasks from Holtercare-Bench, evaluated by additional BLEU n-gram overlap metrics.
Model
Modality
Statistical Overview
General Summary
BLEU-1 ↑
BLEU-4 ↑
BLEU-1 ↑
BLEU-4 ↑
Generalist Models
GPT-5-mini
44.64
3.65
60.47
6.95
Claude-4.5-Haiku
15.92
1.15
27.60
1.00
Phi-4-mini-3.8B
56.76
10.99
52.43
6.03
Phi-4-mini-3.8B FT
97.67
68.03
94.83
71.94
Appendix
Table 10. Supplementary performance comparison of evaluated models on Report Generation tasks from Holtercare-Bench, evaluated by additional BLEU n-gram overlap metrics.
Model
Modality
Presence
Event Counting
Event Timing
HR Extremum Timing
Diagnosis
Generalist Models
InternVL-3.5-8B
58.01
29.66
47.26
31.85
39.37
MiniCPM-V4.5-8B
54.90
51.38
28.05
35.99
26.38
Gemini-3.0-Flash
67.32
14.98
62.50
53.18
41.73
Qwen3-VL-8B
60.95
31.80
28.66
34.71
32.28
Qwen3-VL-8B FT
95.10
83.79
97.23
71.97
94.88
Appendix
Table 11. Supplementary performance comparison of video-capable models evaluated under the text modality on Closed-QA tasks from Holtercare-Bench, evaluated by accuracy.
Model
Modality
Presence
Event Counting
Event Timing
HR Extremum Timing
Diagnosis
Phi-4-mini-3.8B
1.95×10−5
3.99×10−16
6.33×10−20
3.09×10−8
1.76×10−11
Qwen3-VL-8B
6.17×10−41
5.26×10−32
2.18×10−52
6.57×10−18
3.55×10−35
Qwen3-VL-8B
7.08×10−44
3.14×10−36
6.14×10−47
1.08×10−17
1.30×10−28
Appendix
Table 12. Statistical significance analysis of improvements from zero-shot baselines to fine-tuned models on Closed-QA tasks from Holtercare-Bench. The reported p -values are derived from McNemar tests.