Physiological Changes and Cardiovascular Investigations in Pregnancy

Profound physiological changes in the maternal cardiovascular system occur shortly after conception. These may impact upon investigation of healthy and complicated pregnancies. Additionally, concerns regarding fetal exposure to ionising radiation are important considerations testing. This manuscript reviews pertinent disease pregnancy. It is estimated that cardiac complicates approximately 1–2% pregnancies [[1]Cauldwell M. Johnson Jahangiri Roos-Hesselink J. Cardiac interventions surgery pregnancy.Int J Cardiol. 2019; 276: 43-47Abstract Full Text PDF PubMed Scopus (8) Google Scholar]. an cause morbidity mortality during pregnancy postpartum period, accounting for up 15% deaths [[2]Centers Disease Control Prevention. Reproductive HealthPregnancy Mortality Surveillance System. Maternal Infant Health.2020https://www.cdc.gov/reproductivehealth/maternal-mortality/pregnancy-mortality-surveillance-system.htmDate accessed: October 6, 2020Google Significant within weeks conception resulting being a high-risk period women with pre-existing conditions. The stressors also result previously undiagnosed conditions or vulnerabilities becoming apparent review addresses significant how they on investigations relevant system. it safety procedures involving radiation. Knowledge these essential correct diagnosis guiding management does not seek which as pregnancy-related pathological processes, such hypertensive disorders Pregnancy associated 15–25% increase heart rate above baseline, beginning first trimester, peaking third then returning preconception state by 10 days [[3]Visentin S. Palermo C. Camerin Daliento L. Muraru D. Cosmi E. et al.Echocardiographic techniques deformation imaging evaluation patients pregnancies.Biomed Res Int. 2017; 2017: 4139635Crossref (6) Plasma volume increases 40% 24 gestation, disproportionately smaller 30% rise red cell mass leading fall serum haemoglobin level, predisposing dilutional anaemia [[4]Litmanovich D.E. Tack Lee K.S. Shahrzad Bankier A.A. Cardiothoracic pregnant patient.J Thorac Imaging. 2014; 29: 38-49Crossref (14) An early, progressive output occurs second trimesters reach 45% values at weeks. further higher twin, compared singleton, In early increased stroke volume, later due rate, decreases trimester caval compression [[5]Adeyeye V.O. Balogun M.O. Adebayo R.A. Makinde O.N. Akinwusi P.O. Ajayi E.A. assessment normal among Nigerians.Clin Med Insights 2016; 10: 157-162Crossref (7) Systolic, mean arterial, diastolic central systolic blood pressure reduced systemic vascular resistance [[6]Sanghavi Rutherford J.D. Cardiovascular physiology pregnancy.Circulation. 130: 1003-1008Crossref (353) Systolic falls lesser degree than arterial pressure. Blood levels 10–15 mmHg below subsequently rising from 26–28 gestation until delivery. Reduction commences 5 gestation. Vascular reaches its nadir 35–40% baseline mid-second 2 delivery accompanied global compliance. Vasomotor sympathetic activity increased, there substantial activation renin-angiotensin-aldosterone axis Increased respiratory minute ventilation oxygenation, reduces carbon dioxide results alkalosis. There difference between sitting supine oxygen concentration latter half and, term, PaO2 7 lower [[7]Spiropoulos K. Prodromaki Tsapanos V. Effect body position PaCO2 pregnancy.Gynecol Obstet Invest. 2004; 58: 22-25Crossref (17) A 105–106 mmHg, 101–106 [[8]Abbassi-Ghanavati Greer L.G. Cunningham F.G. laboratory studies: reference table clinicians.Obstet Gynecol. 2009; 114: 1326-1331Crossref (443) Mean saturation rest study 100 was 98±0.95% (range 96–100%) [[9]Langford Khwanda A. Langford Oxygen response exercise women: simple protocol range.Obstet Med. 2010; 3: 65-68Crossref Following (100 m walking flat, immediately steps) 97.7±1% 95–100%), 0.32%. Among current smokers, peak 97.0±0.7%. saturations less 95% should be regarded abnormal trigger into possible underlying pathology. Key symptoms signs summarised Table 1.Table 1Physiological signs.Physiological ChangeCardiovascular Symptoms SignsIncrease plasma anaemia, vasodilation, tachycardia15-25% rate; Palpitations common pregnancy; high prevalence arrhythmias however serious rareVasodilationFall late subsequent termIncreased oxygenation ventilationPaO2 <95% abnormal, mandate investigationSpinal anaesthesia atrioventricular (AV) blockAV block usually transient, responds atropine/ephedrine Open new tab During labour, pain uterine contractions 20% output. maximum 60–80% prior onset labour. Normal vaginal (VD) epidural analgesia characterised reduction index [[10]Ashwal Shinar Orbach-Zinger Lev Gat R. Kedar al.The hemodynamics labor undergoing cesarean deliveries determined whole bioimpedance.Am Perinatol. 2018; 35: 177-183Crossref (4) Elective caesarean section (CS) term following placenta [[11]Robson Hunter Boys Dunlop W. Bryson Changes section.Anaesthesia. 1989; 44: 475-479Crossref (32) remain elevated end operation. CS spinal anaesthesia, bioimpedance studies demonstrate [[12]Ram Lavie Blecher Y. Amikam U. Shulman al.Cardiac before, elective under anesthesia low-risk women.J 37: 793-799Crossref (15) At moment CS, whole-body impedance cardiography demonstrated sudden 47% 39% resistance, persisting minutes [[13]Tihtonen Koobi T. Yli-Hankala Uotila assessed cardiography.Acta Gynecol Scand. 2005; 84: 355-361Crossref (39) remained stable. Levels troponin I (cTnI) creatine kinase-MB (CK-MB) unchanged normotensive [[14]Morton Teasdale Review article: woman emergency department - part 1: investigations.Emerg Australas. 30: 600-609Crossref High sensitivity cTnI 99th centile TnI assay 2% women, although individuals were tested heterophile antibodies [[15]Ravichandran Woon S.Y. Quek Y.S. Lim Y.C. Noor E.M. Suresh al.High-sensitivity pregnancy.Am 132: 362-366Abstract (13) Most have shown brain natriuretic peptide (BNP) pre-conception One longitudinal 29 showed no differences BNP throughout double those non-pregnant controls [[16]Hameed A.B. Chan Ghamsary Elkayam Longitudinal B-type postpartum.Clin 32: E60-E62Crossref (76) biomarkers therefore useful assessing antepartum presenting suspicious myocardial injury left ventricular dysfunction. unaffected biochemical markers diagnosing [[17]Koscica K.L. Bebbington Bernstein P.S. Are affected delivery?.Am 21: 31-34Crossref (11) CK- MB postpartum, interval reported 36% women. unhelpful ischaemia peripartum [[18]Leiserowitz G.S. Evans A.T. Samuels S.J. Omand Kost G.J. Creatine kinase isoenzyme period.J Reprod 1992; 910-916PubMed two- threefold 48 hours 6.1% post-partum having greater ng/L [[19]Burlingame J.M. Yamasato Ahn H.J. Seto Tang W.H.W. echocardiography reflect pregnancy.J Perinat 45: 577-583Crossref (21) Scholar,[20]Yoshimura Yoshimura Yasue H. Ito Okamura Mukoyama al.Plasma atrial human Endocrinol. 1994; 140: 393-397Crossref (59) postulated this relates uteroplacental transfusion, release vena obstruction mobilisation extravascular fluid. return 6–12 postpartum. Mild elevation represent change Serum potassium magnesium 0.2–0.3 mmol/L regard possibility electrolyte contributing Human chorionic gonadotropin (hCG) act thyroid stimulator alpha-subunit stimulating hormone (TSH). Ten per cent (10%) transiently suppressed TSH free thyroxine triodothyronine seen hyperemesis gravidarum gestational trophoblastic hCG mediated thyrotoxicosis differentiated Graves’ absence TSH-receptor antibodies. who found function tachycardia require treatment, whereas anti-thyroid drug therapy. White (WBC) count neutrophil leucocytosis. typical WBC 6–16x109/L, though rises markedly uncomplicated upper level 29x109/L clinically patient where clinician swayed marked consider infection rather acute dyspnoea. D-dimer steadily 15–50%, 67–78% 96–100% non-pregnancy threshold first, respectively. Pregnancy-specific thresholds been validated. lipids total cholesterol, LDL-cholesterol triglycerides 3-fold, 1.5- fold 1.7-fold respectively [[21]Alvarez J.J. Montelongo Iglesias Lasuncion M.A. Herrera lipoprotein profile, density subclass, postheparin lipases Lipid Res. 1996; 299-308Abstract cholesterol clinical significance, critical hypertriglyceridaemia risk pancreatitis. summary pathology pregnancy.Table 2Considerations pregnancy.Physiological Change Healthy PregnancyImplications InvestigationcTnI peripartumElevated marker coronary syndrome pregnancyPhysiological CK-MB postpartumCK-MB peripartumBNP mildly postpartumMildly physiologicalD-dimer progressively pregnancyD-dimer testedMarked peripartumHigh indicative infectionInvestigation endocrine causes hypertension hormones pregnancyAwareness diagnostic criteria primary aldosteronism Cushing syndromeIncreased stimulator10% treatmentAbbreviations: WBC, white count; BNP, peptide; CK-MB, kinase-MB; hCG, gonadotropin; TSH, hormone. Abbreviations: electrocardiography (ECG) QRS describe overall slight shift only 4–6° extremely variable [[22]Carruth J.E. Mivis S.B. Brogan D.R. Wenger N.K. electrocardiogram Heart 1981; 102: 1075-1078Crossref (46) one 157 rightward 22%, 29%, leftward 49%. Left attributable diaphragm, size mass, rotation displacement enlarging uterus. incidence prominent Q waves inferior anterolateral leads, T wave flattening/inversion lead III V1–V3. P-wave duration increases, plateauing trimester. Maximal QTc remains ranges. rhythm monitoring discloses asymptomatic Twenty-four (24)-hour Holter recordings performed volunteers 6 decreased all indices variability consistent autonomic modulation [[23]Stein P.K. Hagley M.T. Cole P.L. Domitrovich P.P. Kleiger R.E. Rottman J.N. 24-hour 1999; 180: 978-985Abstract premature complexes (APCs) isolated (VPCs) 58% 50% [[24]Shotan Ostrzega Mehra J.V. Incidence relation palpitations, dizziness, syncope.Am 1997; 79: 1061-1064Abstract (167) More APCs hour 4% more 50 VPCs multifocal occurred Repeat disclosed contractions. 261 without previous cardio-respiratory 11.5% experienced palpitations [[25]Choi H.S. Han S.S. Choi H.A. Kim C.G. Y.Y. al.Dyspnea palpitation pregnancy.Korean Intern 2001; 16: 247-249Crossref Palpitations, dizziness syncope most reasons referral obstetric clinic, accounted referrals cardiology clinic devoted Scholar,[26]Cruz Hibbard J.U. Alexander Briller Ambulatory arrhythmia palpitations.Am 2013; 53-58PubMed recording structural 10% symptomatic episodes Scholar] Cruz al. evaluated 96 referred cardiologists performing either (n=19) event loop recorder (n=65) [[26]Cruz Arrhythmias defined supraventricular tachycardia, fibrillation flutter, complete block. Eight had history congenital disease, whom Three (3) dysfunction time evaluation. documented (5%) group, 14 (21.5%) recorder. obesity eight-fold four-fold authors concluded superior detecting [[27]Kinlay Leitch J.W. Neil Chapman B.L. Hardy D.B. Fletcher P.J. recorders yield diagnoses cost-effective 48-hour palpitations. controlled trial.Ann 124: 16-20Crossref Seven stress testing [28Heenan A.P. Wolfe L.A. Davies G.A. gestation: responses.Obstet 97: 127-134Crossref Scholar, 29MacPhail Victory 2000; 96: 565-570Crossref (42) 30Szymanski L.M. Satin A.J. Exercise pregnancy: responses public health guidelines.Obstet 2012; 119: 603-610Crossref (73) 31Veille J.C. Kitzman D.W. Millsaps P.D. Kilgo filling stationary bicycle period.Am 185: 822-827Abstract 32Asher U.A. Ben-Shlomo I. Said Nabil effects induced electrocardiogram.Br Gynaecol. 1993; 100: 41-45Crossref 33van Doorn M.B. Lotgering F.K. Struijk P.C. Pool Wallenburg H.C. strenuous exercise.Am 166: 854-859Abstract (37) 34Dominguez De Smoler P.E. Armas Dominguez Karchmer Skromne [Electrocardiography, trimester].Arch Inst Cardiol Mex. 1976; 46: 74-81 [In Spanish]PubMed 12 35th 39th week ST depression nine (75%) [[34]Dominguez 15 singleton underwent tests (a Modified Bruce producing 85% age predicted maximum) 13% 75% 37 that, view segment changes, role (Table 3).Table 3Alterations ECG (echo) pregnancy.Alteration InvestigationST segmental hypokinesis echoST significance pregnancyST pregnancyExercise pregnancyDilation chambers (seen TTE)Mild severity valvular regurgitation pregnancyTTE overestimate pulmonary artery pregnancyConsider RHC suspected hypertensionPericardial effusions pregnancyPericardial effusion pregnancyAbbreviations: ECG, electrocardiograph; TTE, transthoracic echocardiography; RHC, right catheterisation; section. Electrocardiograph predominantly depression, noted 25–47% regardless method [[35]Mathew J.P. Fleisher Rinehouse J.A. Sevarino F.B. Sinatra R.S. Nelson A.H. al.ST delivery.Anesthesiology. 77: 635-641Crossref (52) Scholar,[36]Palmer C.M. Norris M.C. Giudici Leighton DeSimone C.A. electrocardiographic regional anesthesia.Anesth Analg. 1990; 70: 36-43Crossref (56) commonly around 30 Transthoracic (TTE) did reveal any evidence wall abnormalities, displayed decrease ejection fraction depression. No Studies examining frequency revealed inconsistent results. Upshaw 13 monitored continuously labour delivery, including atrial, nodal complexes, sinoatrial arrest, wandering pacemaker paroxysmal repolarisation [[37]Upshaw Jr., C.B. electrocardiograms recorded delivery.Am 1970; 107: 17-27Abstract (22) None significant. Palmer 8 22 (40%) peripartum, several runs brief episode [[38]Palmer period.Int Anesth. 63-66Abstract (5) Berlinerblau 1 [[39]Berlinerblau Yessian Lichstein Haberman Oruci Jewelewicz delivery.Gynecol 52: 128-131Crossref (9) Fifty-seven (57%) minor arrhythmias, while complex arrhythmias—one couplets triplets, other multiple VPCs. frequent