\documentclass[10pt]{article}

\usepackage{fullpage}
\usepackage{setspace}
\usepackage{parskip}
\usepackage{titlesec}
\usepackage[section]{placeins}
\usepackage{xcolor}
\usepackage{breakcites}
\usepackage{lineno}
\usepackage{hyphenat}





\PassOptionsToPackage{hyphens}{url}
\usepackage[colorlinks = true,
            linkcolor = blue,
            urlcolor  = blue,
            citecolor = blue,
            anchorcolor = blue]{hyperref}
\usepackage{etoolbox}
\makeatletter
\patchcmd\@combinedblfloats{\box\@outputbox}{\unvbox\@outputbox}{}{%
  \errmessage{\noexpand\@combinedblfloats could not be patched}%
}%
\makeatother


\usepackage{natbib}




\renewenvironment{abstract}
  {{\bfseries\noindent{\abstractname}\par\nobreak}\footnotesize}
  {\bigskip}

\titlespacing{\section}{0pt}{*3}{*1}
\titlespacing{\subsection}{0pt}{*2}{*0.5}
\titlespacing{\subsubsection}{0pt}{*1.5}{0pt}


\usepackage{authblk}


\usepackage{graphicx}
\usepackage[space]{grffile}
\usepackage{latexsym}
\usepackage{textcomp}
\usepackage{longtable}
\usepackage{tabulary}
\usepackage{booktabs,array,multirow}
\usepackage{amsfonts,amsmath,amssymb}
\providecommand\citet{\cite}
\providecommand\citep{\cite}
\providecommand\citealt{\cite}
% You can conditionalize code for latexml or normal latex using this.
\newif\iflatexml\latexmlfalse
\providecommand{\tightlist}{\setlength{\itemsep}{0pt}\setlength{\parskip}{0pt}}%

\AtBeginDocument{\DeclareGraphicsExtensions{.pdf,.PDF,.eps,.EPS,.png,.PNG,.tif,.TIF,.jpg,.JPG,.jpeg,.JPEG}}

\usepackage[utf8]{inputenc}
\usepackage[english]{babel}



\usepackage{float}








\begin{document}

\title{Normalization of P-wave Axis After CTI Ablation}



\author[1]{Parth Makker}%
\author[2]{Eric Dulmovits}%
\author[3]{Stuart Beldner}%
\affil[1]{Lenox Hill Hospital}%
\affil[2]{North Shore University Hospital}%
\affil[3]{Northwell Health}%


\vspace{-1em}



  
  \date{June 15, 2024}


\begingroup
\let\center\flushleft
\let\endcenter\endflushleft
\maketitle
\endgroup





\selectlanguage{english}
\begin{abstract}
We report a case of superiorly directed sinus p-waves in a young patient
who had extensive right atrial scarring due to prior right atriotomies.
This sinus p-wave axis then changed to inferiorly directed after
catheter ablation of the cavo-tricuspid isthmus (CTI). Normal p-wave
morphology during sinus rhythm has been described as having an axis
between 0 to +75 degrees. However, this is contingent upon an otherwise
healthy atrium without conduction abnormalities. Our case highlights a
young patient who has undergone two mitral valve surgeries, and as a
result, two right atriotomies for cardiopulmonary bypass. During
follow-up after the second surgery, his unusual p-wave axis was noted
and it was unclear whether it was due to an atrial escape rhythm that
had overtaken the sinus node or abnormal conduction of sinus rhythm.
Electroanatomic activation mapping proved that he indeed had a sinus
rhythm with conduction abnormality along the sites of his previous
atriotomies. Additional ablation on the other side of the sinus node
exit resulted in pseudo-normalization of his p-wave axis morphology.
Four week follow up showed persistent inferiorly directed P wave, a
finding in this patient consistent with persistent block across the
caval tricuspid isthmus.%
\end{abstract}%



\sloppy


\textbf{Normalization of P-wave Axis After CTI Ablation}

Parth Makker MD\textsuperscript{1}, Eric Dulmovits
MD\textsuperscript{1}, Stuart Beldner MD FHRS\textsuperscript{1}

Northwell Health - 300 Community Dr, Manhasset, NY 11030

Corresponding Author:

Parth Makker

11 East 12\textsuperscript{th} St, Apt 1F

New York, NY 10003

The authors have no conflicts of interest to disclose

The authors did not receive funding for this case report

Word Count: 569 words



\textbf{Introduction:}

Electrocardiographic (ECG) criteria for p-wave morphology in sinus
rhythm requires a left-inferior axis (0.0 to +75
degrees).\textsuperscript{1} However, the normal p-wave morphology can
be altered by physiologic or post-surgical changes in the right or left
atrium due to enlargement of the atria or scarring.\textsuperscript{1,
2}

We report a case of superiorly directed sinus p-waves in a young patient
who had extensive right atrial scarring due to prior right atriotomies.
This sinus p-wave axis then changed to inferiorly directed after
catheter ablation of the cavo-tricuspid isthmus (CTI).

\textbf{Case:}

Our patient is a 32-year-old man with a history of severe mitral
regurgitation who underwent a mechanical mitral valve replacement at the
age of 7. Multiple chordae had ruptured on his anterior mitral valve
leaflet and his posterior leaflet had eroded beyond hope of repair. He
did well until the age of 25 when he presented with heart failure and
had evidence of patient-prosthesis mismatch. He then underwent a redo
sternotomy and a bioprosthetic mitral valve replacement and had an
uneventful recovery. His yearly ECGs from the age of 25-32 revealed a
superiorly directed p-wave morphology. He was asymptomatic during this
time period with a very active lifestyle (sometimes \textgreater{}40,000
steps/day) (Figure 1). At the age of 32, he presented with vague
symptoms of lightheadedness and was noted to be in atrial flutter
(Figure 2).

He was taken for a catheter ablation of atrial flutter. Activation and
entrainment mapping confirmed the rhythm to be typical, i.e. caval
tricuspid isthmus dependent flutter. Qian et al studied atrial
tachycardias and reported a high sensitivity and specificity (88 and
89\%) for a low right septal (coronary sinus ostium or tricuspid
annular) site of origin for his pre-flutter P
wave.\textsuperscript{3}Out of concern for possibly ablating his atrial
pacemaker during caval tricuspid isthmus ablation, the decision was then
made to cardiovert the patient and map the ``sinus focus''. Wide splits
were noted contiguously in the posterior right atrium from the SVC to
the IVC resulting in a line of conduction block. The site of earliest
right atrial activation was noted to be sufficiently distant to the
targeted line of CTI ablation. Atrial activation was noted to be
primarily caudo-cranial (Figure 3, Panel A). CTI ablation was performed
and bidirectional block was confirmed with differential atrial pacing. A
new sinus rhythm map was created post-CTI ablation. Atrial activation
post-ablation was now noted to be primarily cranio-caudal (Figure 3,
Panel B) and the surface ECG now revealed inferiorly directed p-waves
(Figure 4).

\textbf{Discussion:}

Normal p-wave morphology during sinus rhythm has been described as
having an axis between 0 to +75 degrees. However, this is contingent
upon an otherwise healthy atrium without conduction abnormalities. Our
case highlights a young patient who has undergone two mitral valve
surgeries, and as a result, two right atriotomies for cardiopulmonary
bypass. During follow-up after the second surgery, his unusual p-wave
axis was noted and it was unclear whether it was due to an atrial escape
rhythm that had overtaken the sinus node or abnormal conduction of sinus
rhythm. Electroanatomic activation mapping proved that he indeed had a
sinus rhythm with conduction abnormality along the sites of his previous
atriotomies. Additional ablation on the other side of the sinus node
exit resulted in pseudo-normalization of his p-wave axis morphology.
Four week follow up showed persistent inferiorly directed P wave, a
finding in this patient consistent with persistent block across the
caval tricuspid isthmus.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image1/image1}

\end{center}
\end{figure}

Figure 1: ECG after 2\textsuperscript{nd} MVR. Atrial rhythm with
superiorly directed p-wave morphology.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image2/image2}

\end{center}
\end{figure}

Figure 2: Typical atrial flutter with variable AV block.

\textbf{Hosted file}

\verb`image3.emf`  available at \url{https://authorea.com/users/368495/articles/487594-normalization-of-p-wave-axis-after-cti-ablation}

Figure 3: A - RAO (left), LAO (right), RAO Caudal (bottom) view of the
right atrium with activation mapping during sinus rhythm prior to CTI
ablation. B - RAO (left), LAO (right), RAO Caudal (bottom) view of the
right atrium with activation mapping during sinus rhythm after CTI
ablation.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image4/image4}

\end{center}
\end{figure}

Figure 4: ECG after CTI ablation

\textbf{Discussion:}

1. O'Keefe JH. The complete guide to ECGs. 2nd ed. Physicians' Press;
2002:512 p.

2. Bo H, Heinzmann D, Grasshoff C, et al. ECG changes after percutaneous
edge-to-edge mitral valve repair. Clin Cardiol. Nov
2019;42(11):1094-1099. doi:10.1002/clc.23258

3. Zhi-Yong Qian~1,~Xiao-Feng Hou,~Dong-Jie Xu,~Bing Yang,~Ming-Long
Chen,~Chun Chen,~Feng-Xiang Zhang,~Qi-Jun Shan,~Ke-Jiang Cao,~Jian-Gang
Zou

An algorithm to predict the site of origin of focal atrial
tachycardia.{[}Pacing Clin Electrophysiology. 2011{]} d. PMID:~21091746.
DOI:~10.1111/j.1540-8159.2010.02980.x

\selectlanguage{english}
\FloatBarrier
\end{document}

