Azygos Vein ICD Lead Implantation Lowers Defibrillation Threshold in a Patient with Hypertrophic Cardiomyopathy

Round 1

Reviewer 1 Report

The authors of this manuscript describe a clinical case of 14 year-old boy with hypertrophic cardiomyopathy and recurrent VF for which dual-chamber ICD implantation had been implanted, however defibrillation threshold test-ing had been ineffective. The authors attempted an new approach - implantation of a trans-venous defibrillation coil lead in the azygos vein, that turned out to be a successful solution to the problem.

I have the following comments and recommendation to the authors of this manuscript:

In the title  “…and massive left ventricular hypertrophy” can be omitted

In the abstract “A 14 years-old male boy….” – leave only “A 14 years-old boy” or ”A 14 years-old male patient”

In the abstract “…since the age of 1 y.o….” should be changed to “…diagnosed at the age of 1 y.o..”

In introduction: “…massive left ventricular hypertrophy (LVH) at age of 13 years” should be “… by the age of 13 years…”

All described events happened in 2015. It is now 2021. What was the fate of this patient during the follow-up? Is he alive and in what clinical condition? Any complications or new interventions?

There are no distinct “Introduction”, “Case presentation”, “Discussion“ and “Conclusions” sections in the manuscript.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

I have read with interest this case report, in which the authors illustrate the efficacy of azygous vein ICD lead implantation in an HCM patient with massive hypertrophy and high DFT. I consider that this case report is very interesting and the authors adequately managed this very complex case. 

1. Azygos vein coil implantation has been described as an alternative to optimize DFTs. I recommend presenting their results regarding this interesting case, referring to other studies on this topic.
2. The English need to be improved because there are some gaps.
3. All abbreviations must be explained from the first time when they are mentioned in the text, even they are common to us, cardiologists.
4. The authors' contributions, funding, informed consent statement, and institutional review board statement need to be completed.

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Dear Authors,

You have worked on the Reviewer's recommendations, however your manuscript needs further corrections (improvement) before being considered for publication:

Major corrections/additions:

1. No Introduction (background) is present in manuscript.

2. Please, start the "Discussion", discussing first your own results: explain your decisions, discuss the alternatives, compare your results to the results of other authors (whenever possible), etc. A very good beginning of the “Discussion” could be the initial part of the first sentence of “Conclusion”: “Our clinical case illustrates that azygous vein ICD lead implantation is efficacious in HCM with massive hypertrophy and high DFT…”, or something like that.Minor corrections:

1. "..mild effort" should be "mild efforts"

 2. Too many "he" are present in the following part of the text: “In December 2008 he suffered a cardiac arrest due to VF while climbing a flight of
stairs. He was successfully resuscitated with external defibrillation, and transported to a local A&E department, where he suffered an electric storm with multiple episodes of VF requiring orotracheal intubation. He was extubated after 24 hours and had no neurological complications. He underwent a dual-chamber ICD (Teligen, Boston Scientific, Inc.), implantation with a dual coil defibrillation ventricular lead."  Find a way to substitute this “he” with other words, wherever possible.

3. “In November 2015 an high shock impedance..." - replace "an"   with "a".

4. The following text is better to be moved to "Discussion": 

“The azygos vein originates at the level of first/second lumbar vertebrae from tributaries of the renal and lumbar veins and runs along the rightward side of the vertebral column, joining the posterior aspect of the superior vena cava slightly superiorly to the upper border of the right main stem bronchus. Azygos vein has the great anatomical advantage of being posterior to the heart and studies have demonstrated a DFT decrease with a combination shock pathway that includes a coil in the azygos vein” 

Author Response

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Author Response File: Author Response.docx

Round 3

Reviewer 1 Report

Dear Editors,

The authors of the current manuscript have observed the recommendations of the reviewers and have significantly improved the quality of their work. 

The manuscript can now be reconsidered for publication in its current version.