Pregnancy is a physiologicnl co!ldition, hut prcsencc of heart diseasc in pregnancy is an important cause of maternal ~llorhidity and morlality and also influences the out come of the fctus. Significant casdio-circulatory changes occur during pregnancy and peripiu-tum period which can lead to dclerioration in patients with heart disease.
Durii~g normal pregnancy there are changes in various cardiocirculatory system and hernodynamics theory as follow:
1) Blood Volume: The blood volunle increascs substantially starting at sixth week of prcgnancy which rapidly rises till inid prcgnancy and continues to rise slowly later, Thc increasc in blood volume varies lrom 20 to 100 per cent with an averagc oC 50 per cent. Highcr increases occur in 111ultigravidas and in ~nultiple pregnancies. The incrcasc in blood volume has some correlation wilh fetal weight, placental mass, and weight of products of conception. The hemoglobin concentration T;llls during pregnancy bccause of rapid increasc in blood volume coinpxed to increasc in red blood cell mass causing physiological rulernia of pregnancy. This can be partially corrected by iron therapy. The changes in blood volume has becn attributed to estrogen ~ncdiated stimulntion of the rcnin aldosterone syslcm resulting in sodium and water rctcnticln. Other llorn~ones like deoxycorlicostcroi~c, prolactin, growth hormone may also he involved in water retention during pregnancy.
2)Heart Rate, Cardiac Output, Stroke Volume: Heart rate increases during pregnancy and peaks during third trimester with an average increase of 10 lo 20 beatslln. In some women, it may incrcase still higher particularly in pregilancy with multiple fctuscs, The cardiac output increases by 50 per cent, starts to risc from SifLh weck, renchcs platcau nt 24'" week and may risc slightly there after. In the third triir~esler, the cardiac output is morc in lateral position than in supine position, owing to venacaval compression by gravid uterus in supine pusition.The increasc in cardiac output is due to incrcase in strolc volume in the euly pregnancy while in the third trimester; it is duc to increase in heart mte.
3) Blood Pressure: 'rhc syslctllic arteiial pressure starts to fall during first trimester,maximum fall in inid pregnancy zind returns to prc-gestational levels before term.The pulse pressure widens because of grcntcr fill1 in diastolic pressure. Reduction in systemic vascular resistancc due to reduced vascular tone is responsible for fall in blood pressure. Gestational hormonal activity, incrcascd level of prostaglandins, increased heat production by developing fetus, creation of low resistance circulation by the devcloping fetus in pregnant uterus, may mediate reduced vascular tone,
'
4) Supine Hypotcnsive Syndrome of Pregnancy: This occurs with significant decrease in heart rate and blood pressure in about 1 I per cent of pregnant women in supine posture, due to comnpression and acute occlusion of the inferior venacava by enlarged uterus. The common symptoms associAted with thisCardiovascular Relalecl Disorderssyndrome include weakness, light headedness, nausea, dizziness and even syncope. These are abolished by turning to one side.
5) Hemsdynamic Changes: During labor and delivery changes in hen~odynamics occur due to anxiety, pain and uterine contractions. Oxygen consumption is increased by three times, Cardiac output increases, blood pressure increases markedly during uterine contractions particularly in second stage of labor.Caesarian section is frequently recommended for pregnant women with heart disease to avoid hemodynamic changes due to paill and anxiety. But significant hemodynamic changes can occur during intubation and by drugs used for anesthesia and analgesia, blood loss, relief of caval compression, extihation and post operative awakening. Hernodynamic changes also occur during post partum.Increase in venons return from relief of caval compression, shift of blood from contracting uterus to systeniic circulation. This occurs in spite of blood loss during delivery, leading to clinical deterioration in a cardiac patient fi-om increase in cardiac output, ventricular filling pressure and heart rate. The hcart rate and cardiac output return to pre-labor values by one hour after delivery, but blood pressure and stroke volun~e takes 24 hours to return to pre-labor values. It usually takes 12 to 24 weeks after delivery to return to pre-pregnancy levels.
Durii~g normal pregnancy there are changes in various cardiocirculatory system and hernodynamics theory as follow:
1) Blood Volume: The blood volunle increascs substantially starting at sixth week of prcgnancy which rapidly rises till inid prcgnancy and continues to rise slowly later, Thc increasc in blood volume varies lrom 20 to 100 per cent with an averagc oC 50 per cent. Highcr increases occur in 111ultigravidas and in ~nultiple pregnancies. The incrcasc in blood volume has some correlation wilh fetal weight, placental mass, and weight of products of conception. The hemoglobin concentration T;llls during pregnancy bccause of rapid increasc in blood volume coinpxed to increasc in red blood cell mass causing physiological rulernia of pregnancy. This can be partially corrected by iron therapy. The changes in blood volume has becn attributed to estrogen ~ncdiated stimulntion of the rcnin aldosterone syslcm resulting in sodium and water rctcnticln. Other llorn~ones like deoxycorlicostcroi~c, prolactin, growth hormone may also he involved in water retention during pregnancy.
2)Heart Rate, Cardiac Output, Stroke Volume: Heart rate increases during pregnancy and peaks during third trimester with an average increase of 10 lo 20 beatslln. In some women, it may incrcase still higher particularly in pregilancy with multiple fctuscs, The cardiac output increases by 50 per cent, starts to risc from SifLh weck, renchcs platcau nt 24'" week and may risc slightly there after. In the third triir~esler, the cardiac output is morc in lateral position than in supine position, owing to venacaval compression by gravid uterus in supine pusition.The increasc in cardiac output is due to incrcase in strolc volume in the euly pregnancy while in the third trimester; it is duc to increase in heart mte.
3) Blood Pressure: 'rhc syslctllic arteiial pressure starts to fall during first trimester,maximum fall in inid pregnancy zind returns to prc-gestational levels before term.The pulse pressure widens because of grcntcr fill1 in diastolic pressure. Reduction in systemic vascular resistancc due to reduced vascular tone is responsible for fall in blood pressure. Gestational hormonal activity, incrcascd level of prostaglandins, increased heat production by developing fetus, creation of low resistance circulation by the devcloping fetus in pregnant uterus, may mediate reduced vascular tone,
'
4) Supine Hypotcnsive Syndrome of Pregnancy: This occurs with significant decrease in heart rate and blood pressure in about 1 I per cent of pregnant women in supine posture, due to comnpression and acute occlusion of the inferior venacava by enlarged uterus. The common symptoms associAted with thisCardiovascular Relalecl Disorderssyndrome include weakness, light headedness, nausea, dizziness and even syncope. These are abolished by turning to one side.
5) Hemsdynamic Changes: During labor and delivery changes in hen~odynamics occur due to anxiety, pain and uterine contractions. Oxygen consumption is increased by three times, Cardiac output increases, blood pressure increases markedly during uterine contractions particularly in second stage of labor.Caesarian section is frequently recommended for pregnant women with heart disease to avoid hemodynamic changes due to paill and anxiety. But significant hemodynamic changes can occur during intubation and by drugs used for anesthesia and analgesia, blood loss, relief of caval compression, extihation and post operative awakening. Hernodynamic changes also occur during post partum.Increase in venons return from relief of caval compression, shift of blood from contracting uterus to systeniic circulation. This occurs in spite of blood loss during delivery, leading to clinical deterioration in a cardiac patient fi-om increase in cardiac output, ventricular filling pressure and heart rate. The hcart rate and cardiac output return to pre-labor values by one hour after delivery, but blood pressure and stroke volun~e takes 24 hours to return to pre-labor values. It usually takes 12 to 24 weeks after delivery to return to pre-pregnancy levels.
 |
| Circulatory Changes in Pregnancy |
6 ) Murmurs in Pregnancy
a) Innocent systolic murmur is heard in most pregnant women as a result of hyperkinetic circulation of pregnancy. It is usually mid systolic, soft, heard at the lower left sternal edge and pulmonary area radiating to supra sternal region and to left side of neck.
b) Cervical venous hum heard over right supra clavicular fossa.
c) Mammary soffle systolic or continuous heard over the breast, late in gestation or in lactating period caused by increased flow in maminary arteries, may decrease or vanish when pressure is applied by the stethoscope or when patient moves to efect position.
may be heard because of increased flow across atrio
d) Short diastolic ll~urr-nu~
ventricular valves.7) Chest X-ray during Pregnancy: With the advent of echocardiography, most of the cardiovascular lesions can be assessed and hence the need for chest X-ray during pregnancy for cardiac evaluation is practically not needed. The radiation dose associated with routine chest X-ray is minimal, but the potential for adverse biological effects from ally an~ount of exposure to radiation during pregnancy need to be avoided. However, if chest X-ray is a must, the abdomell and pelvic area need to be covered with lead material. The findings in the chest X-ray during nornlal pregnancy may simulate cardiac diseases and should be interpreted with caution. Strengthening of the left upper cardiac border, horizontal position of the heart secondary to elevated diaphragm, increased lung markings ]nay be seen.Small pleural effusions may be found post partum, which may re-absorb within 1-2 weeks after deliveiy. Exposure of the embryo to radiation during first I0 days after conceition would most likely cause no effect or leads Lo resorption.Exposure from 10 days to 50 days radiation may have teralogenic ei'fcct. Latel;time of exposure may cause inlra uterine growth retardation, central nervous system abnormalities and increased incidence of' cl~ildhood cancec Direct radiation Lo fetus needs to be avoided. Cursent recornmendations arc < 5 rads exposurc - no risk or low risk, 5 to 10 rads counsel regarding'risk, 10 to 15 rads and beyond, termination of pregnancy is advised.Radiation exposure can also occur during balloon ~nitral valvuloplasty for rheumatic mitral stenosis during pregnancy. Thc abdomen is shielded by protective lead material during the procedure. Alternatively, the procedures call be done under ECHO guidance which will avoid radiation exposure.
8)Electrocardiogram(ECG): The electrocardiography is simple non-invasive,patient friendly, reproducible technique that has stood h e test of time fbr morc than hundred years. It is most useful: (1) in the diagnosis and prognosis of acute coronary syndromes, (2) in the diagnosis ol' arrl~ythmias, (3) in heart Sailure in assessing QRS width and rcsynchronization therapy, and (4) genetic arrhythmology e.g. - Long QT Syndrome. ECG is safe and inexpensive investigation. There are some changes in the ECG that can occur in normal pregnancy. These are: (1) QRS axis inay shift to the left or right'but usually is within normal lirnits, (2) a small Q wave and an inverted P wave in Lead I11 that may vary with respiration, (3) a greater Ii wavc amplitude in Lead V2, (4) ST segment depression mimicking myocardial ischemia but not associated with wall motion abnormalities by echo, at the end of pregnancy in patients undergoing caesarian section, and ( 5 ) incrcased susceptibility to arrhythmias during pregnancy as manifested by sinus tachycardia ancl atrial or ventricular prematurc beats. Paroxysmal supra ventricular tachycardia has been reposted during normal pregnancy and also ventricular tacllycardia in otherwise healthy women.
9) Echocardiography: Introduction of echocardiography has revolutionized the diagnosis of most of the cardiac conditions and has replaced other modalities of investigations like cardiac catheterization in the diagnosis of most congenital heart diseases. Echocardiography includes M mode assessment, two dimensional trans thoracic and trans esophageal imaging, Doppler techniques and myocardial contrast imaging. These are non-invasive methods. It is useful iin assessment of various cardiac conditions like congenital heart diseases, ischemic heart diseases,primary myocardial diseases and other conditions.
Use of echocardiography during pregnancy both for mother and for fetus is considered safe. Trans esophageal echocardiography has bcen increasingly used in pregnancy and appears to be well toleratcd by both mother ilnd the fetus. Certain changes that occur during normal pregnancy have been reported. These eqhocardiographic ch<mges are: (1) Progressive increase in all cardiac chamber Ibregnancy and dimensions with about 20 per cent increase in the size of right atrium and right ventricle, 12 per cent in left atrial size and 6 per cent in left ventricular size. These changes return to normal after delivery, but may persist for several montl~s. (2) Early
and progressive dilatation of mitral, tricuspid and pulmonary annuli which may be associated with valvular regurgitation (functional). (3) Small pericardial effusion.
Use of echocardiography is safe for fetus and used to diagnose congenital heart diseases during intrauterine life. Many abnormalities can be detected in first and second trimester of pregnancy.
a) Innocent systolic murmur is heard in most pregnant women as a result of hyperkinetic circulation of pregnancy. It is usually mid systolic, soft, heard at the lower left sternal edge and pulmonary area radiating to supra sternal region and to left side of neck.
b) Cervical venous hum heard over right supra clavicular fossa.
c) Mammary soffle systolic or continuous heard over the breast, late in gestation or in lactating period caused by increased flow in maminary arteries, may decrease or vanish when pressure is applied by the stethoscope or when patient moves to efect position.
may be heard because of increased flow across atrio
d) Short diastolic ll~urr-nu~
ventricular valves.7) Chest X-ray during Pregnancy: With the advent of echocardiography, most of the cardiovascular lesions can be assessed and hence the need for chest X-ray during pregnancy for cardiac evaluation is practically not needed. The radiation dose associated with routine chest X-ray is minimal, but the potential for adverse biological effects from ally an~ount of exposure to radiation during pregnancy need to be avoided. However, if chest X-ray is a must, the abdomell and pelvic area need to be covered with lead material. The findings in the chest X-ray during nornlal pregnancy may simulate cardiac diseases and should be interpreted with caution. Strengthening of the left upper cardiac border, horizontal position of the heart secondary to elevated diaphragm, increased lung markings ]nay be seen.Small pleural effusions may be found post partum, which may re-absorb within 1-2 weeks after deliveiy. Exposure of the embryo to radiation during first I0 days after conceition would most likely cause no effect or leads Lo resorption.Exposure from 10 days to 50 days radiation may have teralogenic ei'fcct. Latel;time of exposure may cause inlra uterine growth retardation, central nervous system abnormalities and increased incidence of' cl~ildhood cancec Direct radiation Lo fetus needs to be avoided. Cursent recornmendations arc < 5 rads exposurc - no risk or low risk, 5 to 10 rads counsel regarding'risk, 10 to 15 rads and beyond, termination of pregnancy is advised.Radiation exposure can also occur during balloon ~nitral valvuloplasty for rheumatic mitral stenosis during pregnancy. Thc abdomen is shielded by protective lead material during the procedure. Alternatively, the procedures call be done under ECHO guidance which will avoid radiation exposure.
8)Electrocardiogram(ECG): The electrocardiography is simple non-invasive,patient friendly, reproducible technique that has stood h e test of time fbr morc than hundred years. It is most useful: (1) in the diagnosis and prognosis of acute coronary syndromes, (2) in the diagnosis ol' arrl~ythmias, (3) in heart Sailure in assessing QRS width and rcsynchronization therapy, and (4) genetic arrhythmology e.g. - Long QT Syndrome. ECG is safe and inexpensive investigation. There are some changes in the ECG that can occur in normal pregnancy. These are: (1) QRS axis inay shift to the left or right'but usually is within normal lirnits, (2) a small Q wave and an inverted P wave in Lead I11 that may vary with respiration, (3) a greater Ii wavc amplitude in Lead V2, (4) ST segment depression mimicking myocardial ischemia but not associated with wall motion abnormalities by echo, at the end of pregnancy in patients undergoing caesarian section, and ( 5 ) incrcased susceptibility to arrhythmias during pregnancy as manifested by sinus tachycardia ancl atrial or ventricular prematurc beats. Paroxysmal supra ventricular tachycardia has been reposted during normal pregnancy and also ventricular tacllycardia in otherwise healthy women.
9) Echocardiography: Introduction of echocardiography has revolutionized the diagnosis of most of the cardiac conditions and has replaced other modalities of investigations like cardiac catheterization in the diagnosis of most congenital heart diseases. Echocardiography includes M mode assessment, two dimensional trans thoracic and trans esophageal imaging, Doppler techniques and myocardial contrast imaging. These are non-invasive methods. It is useful iin assessment of various cardiac conditions like congenital heart diseases, ischemic heart diseases,primary myocardial diseases and other conditions.
Use of echocardiography during pregnancy both for mother and for fetus is considered safe. Trans esophageal echocardiography has bcen increasingly used in pregnancy and appears to be well toleratcd by both mother ilnd the fetus. Certain changes that occur during normal pregnancy have been reported. These eqhocardiographic ch<mges are: (1) Progressive increase in all cardiac chamber Ibregnancy and dimensions with about 20 per cent increase in the size of right atrium and right ventricle, 12 per cent in left atrial size and 6 per cent in left ventricular size. These changes return to normal after delivery, but may persist for several montl~s. (2) Early
and progressive dilatation of mitral, tricuspid and pulmonary annuli which may be associated with valvular regurgitation (functional). (3) Small pericardial effusion.
Use of echocardiography is safe for fetus and used to diagnose congenital heart diseases during intrauterine life. Many abnormalities can be detected in first and second trimester of pregnancy.
 |
| ECG and Echocardiography of the pregnant woman |
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.