During pregnancy the honllonal and henlodynamic changes lhat occm make arrhythmias more likely to occur. The henlodynamic change results in myocardial stretch and an increase in Casdiac dimension, which make lrhythn~ias more likely to occur. Estrogen might have an effect on the expression of cardiac ion channels.Pregnancy might illcrease sympathetic Lone and decrease parasympathetic tone,causing mhythmogenesis. Palpitations are frequent reason for refei~al to cardiologist during pregnancy and cause anxiety to the patient. In one of the studies by Holter monitoring, 76 per cent had no associated arrhythmias and in most cases palpitations were due to sinus tachycardia. During pregnancy, heart rate increases by 20 per cent above base line. The investigations for arrhythmias is by non-invasive worlc up and caution is advised with exercise stress testing and if indicated to be done with a low- level protocol with felal monitoring. When benign arrhythmias are found,reassurance of the patient is needed with an advise to avoid stimulants such as
caffeine.
A) Common arrhythmias and their management during pregnancy
1)Szcpraventricular Tachycardias
caffeine.
A) Common arrhythmias and their management during pregnancy
1)Szcpraventricular Tachycardias
a) Re-entrant tachycardias (Supraventricular)
b) ~ t s i i tachycardia
c)Atfial fibrillation and flutter
2) Ventricular Tachycardias
Re-entrant tachycardias (Supvaventricular): This is the mosl freqently seen tachycardia during pregnancy. The incidence of paroxysmal supraventricular tachycardia is increased during pregnancy. The tachycardia episodes me more sylnplomatic and equally distributed throughout pregnancy. Surface 12 lead ECG is helpful in the diagnosis.Management of an acute episode of supraventricular tachycardia (SVT) i n a pregnant patient is the same as that of a non-pregnant paiient. Vagal maneuvers like eye ball compression, drinking of ice cold water or carotid massage sho~lld be tried first. If tachycardia persists, adenosine to be given intravenously. It is reported tobe effective and safe in the second and third trimester. Fetal monitoring is advised to detect possible bradycardia.Veraparnil is to be avoided because of its prolonged hypotensive effect. If tachycardia persists or if hemodynanic unstability occurs, electric cardioversion is advised. In patients with new onset'of tachycardia,hyperthyroidism should be ruled out. In young woinan with known SVT,radio frequency ablation is advised prior to planned pregnancy.
b) Atrial Tachycardia: Atrial tachycardia is not common without structural heart disease and it is also rare in pregnant women. However, woman with this surhythmia during pregnancy,may have normal heart structure and this arrhythmia may be difficult to treat. It can be refractory to medical treatment and in some patients with incessant tachycardia rate control may be more important to avoid tachycardia induced cardioinyopathy. l'he drugs that are used include f-lecanide, beta-blockers or amiodarone. Generally, this arrhythmia resolves after delivery unless present prior to pregnancy. In general prognosis is good both For mother and fetus.
C)Atrial Fibrillation and Artial Fl~~tter:
These arrhythmias are not common in pregnancy in the absence of structural heart disease or endocrine abnormalities. If these arrhythmias occur during pregnancy without prior history of these arrhythmias, the patient needs to be evaluated for congenital heart disease, rlieumatic valvular disease and hypterthyroidism. Rheumatic mitral stenosis is the conlmonest cause of atrial fibrillation. It can also occur with atrial septa1 defect and from atrial scars from surgical repairs. When atrial fibsillation occurs in mitral stenosis, the rapid ventricular response will be poorly tolerated because of short diaslolic filling time. Hence, in the management of atrial fibrillation during pregnancy, ventricular rate control with atrio-ventricular nodal blocking agents is important. Electrical cardioversion is advocated if spontaneous reversion to sinus rllythm does not occur within 48 hours to avoid the ileed of anticoagulants. Electric cardioversion is also indicated in henlodynamically unstable patients. During and immediately after cardioversion, fetal inonitoring is recornn~endcd.
Antial~hythmic drugs are indicated in recurrent or persistant atrial fibrillation and flulter. The drugs that are used to control ventlici~lar rate in artial fibrillation include digitalis preparations, beta-blockers, ainiodarone and verapainil. Patients with chronic atrial ribrillation, who have increased risk of thromboembolism should be anticoagulated. However, coumadin group of anticoagulants me teratogenic and contraindicated during the first trimester of pregnancy. Heparin does not cross the placenta and is considered to be the &ug of choice. Patients with structural heart disease, rheumatic mitral valvular disease and histoiy of previous embolis~n are at high rist for stroke.
2) Ventricular Tachycardias
Ventricular tachycardia is rare in pregnancy. Life-threatening ventricular tacliycasdias are reported in patients with structural heart diseases or with long QT syndrome. The common type of ventricular tachycardia associated with pregnancy may be due lo catecholamine sensitive type or that associated with idiopathic right ventricular outflow tract tachycardia. However in one review, most pregnant women with ventricular tachycardia did not have structural heart disease and were stress related,responding to beta-blocker therapy. Most of these tachycardias resolved after delivery with good prognosis. In the approach to the evaluation, presence of structural heart disease or long QT syndrome is ascertained by electrocardiogram and echocardiogram. If no abnormalities are detected, idiopalhic right ventricular outflow tTact tachycardia is the most likely mechanism. The features include monornoiphic complexes, left bundle branch block, and inferior axis in the frontal plane of the electrocardiogram. Beta-blocker is the drug of choice in this type of tachycardia. If the patient has long QT syndrome, torsades de pointes is the cause and it may be life threatening and may need electric cardioversion with appropriate medications like administration of potassium if these is hypokalemia. If there is structural heart disease and ventricular tachycardia occurs, there is a risk of sudden cardiac death. Anti arrhythmic drug therapy and possibly Implantable Cardioverter Defibrillator (ICD) may be required. Electric cardioversion is indicated for hernodynamically unstable ventricular tachycardia. Lidocaine is the drug of choice for the acute treatment of more stable tachycardia.
B) Implantable Cardioverter Defibrillators and Pregnancy (ICD)
In a multicenter retrospective study, women who had ICD, who later became pregnant, 75 per cent of patients did not experience shocks duing pregnancy.However, though remaining 25 per cent had shocks only seven per cent had muItiple shocks during pregnancy. Nearly 90 per cent of babies were healthy at delivery, four per cent with low birth weight and two per cent were still born. No lead fracture o r generator erosions were reported, while only one generater migrated to different position as a result of pregnancy. Though ICD is safe in patients with vaginal delivery,it needs to be inactivated during caesarian section because of use 01 eleclrocautery.The more presence of ICD is not a contraindication to pregnancy. However ICD implantation or radio frequency ablations are best accomplished prior to planned pregnancy. During pregnancy, fluoroscopy radiation exposure is harmful for the fetus and may result in conget~ital malfo~mations and mental retardation, especially exposure during first half of pregnancy, while childhood malignancy risk is more if exposed during second half of pregnancy. If absolutely required, electro physiological procedures like lead placement may be done under echocardiographic guidance.
C) Anti Arrhythmic Drugs during Pregnancy
Anti-arrhythmic drugs used in pregnancy causes concern of fetal injury. Most of these drugs are FDA risk category C. Prolonged use of these drugs are avoided except in severe arrhythmias. The risk benefit ratio for the mother and fetus shouId always be considered first. Increased risk of sudden death, tachycardia induced cardiomyopathy, hypotension during tachycardia are main reasons for drug therapy. Digoxin and quinidine have been used for a long time though they have side effects. Class 111 antiarrhythmic agents have better risk profile. But whatever drug is chosen, it is t o be used with lowest effective dosage and frequent monitoring of drug level is needed.Antiarrhythmic drugs are also used to treat fetal tachycardias and digoxin has been found to be useful. Other drugs like quinidine, procainamide, amiodarone and flecanide have also been used. Detailed discussion of antiarrhythmic drugs is done in chapter on pharmacotherapy and pregnancy.
D) Cardioversion
Cardioversion is a method of converting tachy arrhythmias to sinus rhythm. This can be achieved either by using antiarrhythmic drugs or by direct current electric shock.The details of the technic is discussed elsewhere. In short, direct current is delivered to the heart froin chest by using two paddIes smeared with gel, one in front and theother lateral side of left the chest and delivering the electric current shock. This can be. delivered synchronized with ECG - triggered to be delivered at the R wave of QRS complex. Non synchronized shock is delivered in ventricular fibrillation.
During pregnancy, electric cardioversion has been pelformed safely during all stages of pregnancy in patients with tachy arrhythmias in responsive to drug therapy or in those patients with helnodynarnic decompensation. During and immediately lollowing cardioversion, fetal monitolillg is I-ecommended.
b) ~ t s i i tachycardia
c)Atfial fibrillation and flutter
2) Ventricular Tachycardias
Re-entrant tachycardias (Supvaventricular): This is the mosl freqently seen tachycardia during pregnancy. The incidence of paroxysmal supraventricular tachycardia is increased during pregnancy. The tachycardia episodes me more sylnplomatic and equally distributed throughout pregnancy. Surface 12 lead ECG is helpful in the diagnosis.Management of an acute episode of supraventricular tachycardia (SVT) i n a pregnant patient is the same as that of a non-pregnant paiient. Vagal maneuvers like eye ball compression, drinking of ice cold water or carotid massage sho~lld be tried first. If tachycardia persists, adenosine to be given intravenously. It is reported tobe effective and safe in the second and third trimester. Fetal monitoring is advised to detect possible bradycardia.Veraparnil is to be avoided because of its prolonged hypotensive effect. If tachycardia persists or if hemodynanic unstability occurs, electric cardioversion is advised. In patients with new onset'of tachycardia,hyperthyroidism should be ruled out. In young woinan with known SVT,radio frequency ablation is advised prior to planned pregnancy.
b) Atrial Tachycardia: Atrial tachycardia is not common without structural heart disease and it is also rare in pregnant women. However, woman with this surhythmia during pregnancy,may have normal heart structure and this arrhythmia may be difficult to treat. It can be refractory to medical treatment and in some patients with incessant tachycardia rate control may be more important to avoid tachycardia induced cardioinyopathy. l'he drugs that are used include f-lecanide, beta-blockers or amiodarone. Generally, this arrhythmia resolves after delivery unless present prior to pregnancy. In general prognosis is good both For mother and fetus.
C)Atrial Fibrillation and Artial Fl~~tter:
These arrhythmias are not common in pregnancy in the absence of structural heart disease or endocrine abnormalities. If these arrhythmias occur during pregnancy without prior history of these arrhythmias, the patient needs to be evaluated for congenital heart disease, rlieumatic valvular disease and hypterthyroidism. Rheumatic mitral stenosis is the conlmonest cause of atrial fibrillation. It can also occur with atrial septa1 defect and from atrial scars from surgical repairs. When atrial fibsillation occurs in mitral stenosis, the rapid ventricular response will be poorly tolerated because of short diaslolic filling time. Hence, in the management of atrial fibrillation during pregnancy, ventricular rate control with atrio-ventricular nodal blocking agents is important. Electrical cardioversion is advocated if spontaneous reversion to sinus rllythm does not occur within 48 hours to avoid the ileed of anticoagulants. Electric cardioversion is also indicated in henlodynamically unstable patients. During and immediately after cardioversion, fetal inonitoring is recornn~endcd.
Antial~hythmic drugs are indicated in recurrent or persistant atrial fibrillation and flulter. The drugs that are used to control ventlici~lar rate in artial fibrillation include digitalis preparations, beta-blockers, ainiodarone and verapainil. Patients with chronic atrial ribrillation, who have increased risk of thromboembolism should be anticoagulated. However, coumadin group of anticoagulants me teratogenic and contraindicated during the first trimester of pregnancy. Heparin does not cross the placenta and is considered to be the &ug of choice. Patients with structural heart disease, rheumatic mitral valvular disease and histoiy of previous embolis~n are at high rist for stroke.
2) Ventricular Tachycardias
Ventricular tachycardia is rare in pregnancy. Life-threatening ventricular tacliycasdias are reported in patients with structural heart diseases or with long QT syndrome. The common type of ventricular tachycardia associated with pregnancy may be due lo catecholamine sensitive type or that associated with idiopathic right ventricular outflow tract tachycardia. However in one review, most pregnant women with ventricular tachycardia did not have structural heart disease and were stress related,responding to beta-blocker therapy. Most of these tachycardias resolved after delivery with good prognosis. In the approach to the evaluation, presence of structural heart disease or long QT syndrome is ascertained by electrocardiogram and echocardiogram. If no abnormalities are detected, idiopalhic right ventricular outflow tTact tachycardia is the most likely mechanism. The features include monornoiphic complexes, left bundle branch block, and inferior axis in the frontal plane of the electrocardiogram. Beta-blocker is the drug of choice in this type of tachycardia. If the patient has long QT syndrome, torsades de pointes is the cause and it may be life threatening and may need electric cardioversion with appropriate medications like administration of potassium if these is hypokalemia. If there is structural heart disease and ventricular tachycardia occurs, there is a risk of sudden cardiac death. Anti arrhythmic drug therapy and possibly Implantable Cardioverter Defibrillator (ICD) may be required. Electric cardioversion is indicated for hernodynamically unstable ventricular tachycardia. Lidocaine is the drug of choice for the acute treatment of more stable tachycardia.
B) Implantable Cardioverter Defibrillators and Pregnancy (ICD)
In a multicenter retrospective study, women who had ICD, who later became pregnant, 75 per cent of patients did not experience shocks duing pregnancy.However, though remaining 25 per cent had shocks only seven per cent had muItiple shocks during pregnancy. Nearly 90 per cent of babies were healthy at delivery, four per cent with low birth weight and two per cent were still born. No lead fracture o r generator erosions were reported, while only one generater migrated to different position as a result of pregnancy. Though ICD is safe in patients with vaginal delivery,it needs to be inactivated during caesarian section because of use 01 eleclrocautery.The more presence of ICD is not a contraindication to pregnancy. However ICD implantation or radio frequency ablations are best accomplished prior to planned pregnancy. During pregnancy, fluoroscopy radiation exposure is harmful for the fetus and may result in conget~ital malfo~mations and mental retardation, especially exposure during first half of pregnancy, while childhood malignancy risk is more if exposed during second half of pregnancy. If absolutely required, electro physiological procedures like lead placement may be done under echocardiographic guidance.
C) Anti Arrhythmic Drugs during Pregnancy
Anti-arrhythmic drugs used in pregnancy causes concern of fetal injury. Most of these drugs are FDA risk category C. Prolonged use of these drugs are avoided except in severe arrhythmias. The risk benefit ratio for the mother and fetus shouId always be considered first. Increased risk of sudden death, tachycardia induced cardiomyopathy, hypotension during tachycardia are main reasons for drug therapy. Digoxin and quinidine have been used for a long time though they have side effects. Class 111 antiarrhythmic agents have better risk profile. But whatever drug is chosen, it is t o be used with lowest effective dosage and frequent monitoring of drug level is needed.Antiarrhythmic drugs are also used to treat fetal tachycardias and digoxin has been found to be useful. Other drugs like quinidine, procainamide, amiodarone and flecanide have also been used. Detailed discussion of antiarrhythmic drugs is done in chapter on pharmacotherapy and pregnancy.
D) Cardioversion
Cardioversion is a method of converting tachy arrhythmias to sinus rhythm. This can be achieved either by using antiarrhythmic drugs or by direct current electric shock.The details of the technic is discussed elsewhere. In short, direct current is delivered to the heart froin chest by using two paddIes smeared with gel, one in front and theother lateral side of left the chest and delivering the electric current shock. This can be. delivered synchronized with ECG - triggered to be delivered at the R wave of QRS complex. Non synchronized shock is delivered in ventricular fibrillation.
During pregnancy, electric cardioversion has been pelformed safely during all stages of pregnancy in patients with tachy arrhythmias in responsive to drug therapy or in those patients with helnodynarnic decompensation. During and immediately lollowing cardioversion, fetal monitolillg is I-ecommended.
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