Right heart strain

File:Pulm embolism.jpg of approximately 100 beats per minute, large S wave in Lead I, moderate Q wave in Lead III, inverted T wave in Lead III, and inverted T waves in leads V1 and V3.]]

Right heart strain (also right ventricular strain or RV strain) is a medical finding of right ventricular dysfunction{{Cite web|url=http://radiopaedia.org/articles/right-heart-strain|title=Right heart strain {{!}} Radiology Reference Article {{!}} Radiopaedia.org|last=Weerakkody|first=Yuranga|website=radiopaedia.org|access-date=2016-07-12}} where the heart muscle of the right ventricle (RV) is deformed.{{Cite journal|last1=Rudski|first1=Lawrence G.|last2=Lai|first2=Wyman W.|last3=Afilalo|first3=Jonathan|last4=Hua|first4=Lanqi|last5=Handschumacher|first5=Mark D.|last6=Chandrasekaran|first6=Krishnaswamy|last7=Solomon|first7=Scott D.|last8=Louie|first8=Eric K.|last9=Schiller|first9=Nelson B.|date=2010-07-01|title=Guidelines for the echocardiographic assessment of the right heart in adults: a report from the American Society of Echocardiography endorsed by the European Association of Echocardiography, a registered branch of the European Society of Cardiology, and the Canadian Society of Echocardiography|url=http://www.asecho.org/wordpress/wp-content/uploads/2013/05/Echo-Assessment-of-Right-Heart-in-Adults.pdf|journal=Journal of the American Society of Echocardiography |volume=23|issue=7|pages=685–713 (see 704); quiz 786–788|doi=10.1016/j.echo.2010.05.010|pmid=20620859}} Right heart strain can be caused by pulmonary hypertension,{{Cite journal|last1=Koestenberger|first1=Martin|last2=Friedberg|first2=Mark K.|last3=Nestaas|first3=Eirik|last4=Michel-Behnke|first4=Ina|last5=Hansmann|first5=Georg|date=2016-03-01|title=Transthoracic echocardiography in the evaluation of pediatric pulmonary hypertension and ventricular dysfunction|journal=Pulmonary Circulation|volume=6|issue=1|pages=15–29|doi=10.1086/685051|issn=2045-8932|pmc=4860554|pmid=27162612}} pulmonary embolism (or PE, which itself can cause pulmonary hypertension{{Cite journal|last1=Shopp|first1=Jacob D.|last2=Stewart|first2=Lauren K.|last3=Emmett|first3=Thomas W.|last4=Kline|first4=Jeffrey A.|date=2015-10-01|title=Findings From 12-lead Electrocardiography That Predict Circulatory Shock From Pulmonary Embolism: Systematic Review and Meta-analysis|journal=Academic Emergency Medicine |volume=22|issue=10|pages=1127–1137|doi=10.1111/acem.12769|issn=1553-2712|pmid=26394330|pmc=5306533}}), RV infarction (a heart attack affecting the RV), chronic lung disease (such as pulmonary fibrosis), pulmonic stenosis,{{cite book|author=Mike Blaivas|title=Emergency Medicine, An Issue of Ultrasound Clinics|url=https://books.google.com/books?id=ErJXAwAAQBAJ&pg=PA229|date=3 April 2014|publisher=Elsevier Health Sciences|isbn=978-0-323-29021-0|page=229}} bronchospasm, and pneumothorax.

When using an echocardiograph (echo) to visualize the heart,{{efn|The apical-four-chamber (A4C) view is best to visualize right heart strain by echo.}} strain can appear with the RV being enlarged and more round than typical. When normal, the RV is about half the size of the left ventricle (LV). When strained, it can be as large as or larger than the LV. An important potential finding with echo is McConnell's sign, where only the RV apex wall contracts;{{Cite book|url=https://books.google.com/books?id=5y5bQQVh2x8C|title=Vascular Emergencies: Expert Management for the Emergency Physician|last1=Rogers|first1=Robert L.|last2=Scalea|first2=Thomas|last3=Geduld|first3=Heike|date=2013-04-04|publisher=Cambridge University Press|page=208|isbn=9781107035027|language=en}} it is specific for right heart strain and typically indicates a large PE.{{Cite journal|last1=Walsh|first1=Brooks M.|last2=Moore|first2=Christopher L.|date=2015-09-01|title=McConnell's Sign Is Not Specific for Pulmonary Embolism: Case Report and Review of the Literature|journal=The Journal of Emergency Medicine|volume=49|issue=3|pages=301–304|doi=10.1016/j.jemermed.2014.12.089|pmid=25986329}}

On an electrocardiogram (ECG), there are multiple ways RV strain can be demonstrated. A finding of S1Q3T3{{efn|Indicative of a prominent S wave in lead I, a Q wave in lead III, and an inverted T wave in lead III,{{Cite book|url=https://books.google.com/books?id=wQ6Ivvhvy-AC&q=S1Q3T3&pg=PA259|title=ECG Interpretation: From Pathophysiology to Clinical Application|last=Kusumoto|first=Fred M.|date=2009-04-21|publisher=Springer Science & Business Media|page=259|isbn=9780387888804|language=en}} which is also known as the McGinn–White sign}} is an insensitive{{Cite book|url=https://books.google.com/books?id=YqJHDAAAQBAJ|title=Oxford Textbook of Medicine: Cardiovascular Disorders|last1=Warrell|first1=Emeritus Professor of Tropical Medicine David|last2=Cox|first2=Timothy|last3=Dwight|first3=Jeremy|last4=Firth|first4=Consultant Physician and Nephrologist John|date=2016-06-16|publisher=Oxford University Press|page=527|isbn=9780198717027|language=en}} sign of right heart strain.{{Cite book|url=https://books.google.com/books?id=yDKxpw25-YsC&q=S1Q3T3&pg=PA290|title=12-Lead ECG|last1=Garcia|first1=Tomas B.|last2=Holtz|first2=Neil|date=2011-11-15|publisher=Jones & Bartlett Publishers|page=347|isbn=9781449677893|language=en}} It is non-specific (as it does not indicate a cause) and is present in a minority of PE cases.{{Cite book|url=https://books.google.com/books?id=yDKxpw25-YsC&q=S1Q3T3&pg=PA290|title=12-Lead ECG|last1=Garcia|first1=Tomas B.|last2=Holtz|first2=Neil|date=2011-11-15|publisher=Jones & Bartlett Publishers|page=290|isbn=9781449677893|language=en}} It can also result from acute changes associated with bronchospasm and pneumothorax.{{Cite book|url=https://books.google.com/books?id=4tIgCAAAQBAJ|title=Making Sense of the ECG: Cases for Self Assessment, Second Edition|last1=Houghton|first1=Andrew R.|last2=Gray|first2=David|date=2014-06-04|publisher=CRC Press|isbn=9781444181852|page=62|language=en}} Other EKG signs include a right bundle branch block{{Cite journal|last1=Digby|first1=Geneviève C.|last2=Kukla|first2=Piotr|last3=Zhan|first3=Zhong-Qun|last4=Pastore|first4=Carlos A.|last5=Piotrowicz|first5=Ryszard|last6=Schapachnik|first6=Edgardo|last7=Zareba|first7=Wojciech|last8=Bayés de Luna|first8=Antonio|last9=Pruszczyk|first9=Piotr|date=2015-05-01|title=The value of electrocardiographic abnormalities in the prognosis of pulmonary embolism: a consensus paper|journal=Annals of Noninvasive Electrocardiology |volume=20|issue=3|pages=207–223|doi=10.1111/anec.12278|pmid=25994548|pmc=6931801}} as well as T wave inversions in the anterior leads, which are "thought to be the consequence of an ischemic phenomenon due to low cardiac output in the context of RV dilation and strain." Aside from echo and ECG, RV strain is visible with a CT scan of the chest and via cardiac magnetic resonance.{{Cite journal|last=Tadic|first=Marijana|date=2015-12-01|title=Multimodality Evaluation of the Right Ventricle: An Updated Review|journal=Clinical Cardiology|language=en|volume=38|issue=12|pages=770–776|doi=10.1002/clc.22443|pmid=26289321|issn=1932-8737|pmc=6490828}}