Thank you very much for giving me the opportunity to review this article. It is a review that addresses an interesting topic for nursing, especially with regard to the continuing education of nurses.
However, the article requires several modifications and clarifications:
1. Abstract: It is necessary to better connect the ideas presented in the "Results" section, as they are not linked and it is difficult to understand the meaning of some sentences.
2. Background:
- I am surprised that having contextualised the importance of this topic in coronary heart disease, you only mention the indication to perform ECGs for the detection of arrhythmias and not for the detection of signs of ischaemia.
- Better link the sentences of the second paragraph in which various examples are presented.
- Move the last sentence on page 2 "There have been no relevant reviews..." to the next paragraph (insert full stop).
3. The review:
- Search methods: Figure 1 does not exactly reflect the PRISMA scheme, so you should not refer to it. I suggest transforming it to the PRISMA schema or else refer to it as "Search strategy flowchart".
- I recommend updating the PROSPERO register, as in addition to the fact that the completed phases of the review have not been updated, there is an inconsistency in the information reflected. For example, in PROSPERO you had listed nurses working in ambulances in the exclusion criteria, whereas in the current review they are included.
- Search methods: Why didn't you limit the years of publication of the review? This surprises me for several reasons. On the one hand, you have contextualised the need for nurses to acquire this competency in technological changes, advances in treatments, etc. yet you include articles up to 30 years old. The same is true for the training that nurses receive today, as it differs significantly from 20 or 30 years ago. And also, the factors influencing nurses' competencies have been modified over the years by changes in the nursing role and changes in the professional/organisational environment, above all. I consider this to be a very important limitation of this review.
- Synthesis: I consider it necessary and interesting that you add an example or further explanation of how you carried out the qualitative and quantitative analysis of the studies and how you integrated the data from both methodologies.
In this same section, I consider that the fact of having carried out an analysis so guided by the four questions stated in the objectives may have led to the loss of other relevant information, especially from the qualitative studies. I would appreciate an explanation of this.
4. I suggest integrating the information from Table S2 into Table 2.
5. Discussion: Revise the wording of the first paragraph to make the sentences more connected.
Although the comparison between the publications in the review is interesting, more use should be made of the rest of the evidence to compare, support or contrast the results obtained.

Thank you for the effort you have made in responding to all the comments.
I think you have responded to most of my recommendations, however, there are two aspects that I would ask you to work on further:

• Synthesis process: In addition to the changes you have made to the text, I think that, in order to better understand the process, it would be useful to create a table/figure describing the steps you have followed by giving an example.

• While I appreciate your response, I still feel that, as this is a review of a competency, it would have been appropriate to limit the years of the search, in order to provide more current knowledge.

Many thanks to the authors for taking my suggestions into consideration. The elaboration of Table S2 certainly adds rigour to the process of analysis shown in the article.