fetal arrhythmias - wesley ob/gyn arrhythmias final.pdf · fetal systemic disease anemia, distress,...
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Tachyarrhythmia
Differential Diagnosis
Premature Atrial Contractions
Supraventricular Tachycardia
Atrial Flutter
Sinus Tachycardia
Ventricular Tachycardia
Tachyarrhythmia
Making the diagnosis
M-mode
Align cursor through one atria and ventricle
Visualizes relationship
Distinguishes type of arrhythmias
Tachyarrhythmia
Making the diagnosis
Pulse wave doppler
Cursor placed between mitral and aortic
valve
Flow disturbances (regurgitation)
Premature Atrial Contractions
Most common fetal arrhythmia
18-24 wga
Dx: Doppler inflow/outflow or left ventricle
or M-mode
Aggrevating factors
Spontaneous resolution
1% progression to SVT
Premature Atrial Contractions
Management in pregnancy
No treatment needed
Evaluation with fetal echocardiogram
Doppler auscultation q1-4 weeks
F/u US
Resume routine care after 2-3 weeks
Supraventricular Tachycardia
SVT
Most common sustained tachycardia
FHR 240-280 bpm
Accessory pathway vs autonomic
Typically structurally normal
Congenital heart disease up to 5-10%
Dx: 2D, Doppler, M-mode
1:1 conduction
Supraventricular Tachycardia
Management of Pregnancy
Controversial
D/C precipitating factors
Continuously monitor 8-24 hours
Treat if…
Structurally abnormal heart
>33% present
Hydrops
Controversial: delivery after 32-34wga
Consider vaginal delivery
Supraventricular Tachycardia
Management of Pregnancy
Digoxin
Load with 0.5mg IV q6-8h until:
<25% tachycardia or decreased hydrops
Therapeutic
Toxicity
PO administration BID-QID
Digoxin level, BMP, EKG, cardiologist consult
Second-line agents
Atrial Flutter
Sustained tachycardia
FHR:
Atrial 300-500 bpm
Ventricular <100-300 bpm
Often 2:1 or 3:1 conduction
Structurally normal
Structural heart disease up to 20%
Sinus Tachycardia
FHR 180-200
1:1 conduction
Causes:
Maternal pyrexia
Stimulants
Maternal thyrotoxicosis
Fetal systemic disease
Anemia, distress, infections
Ventricular Tachycardia
FHR: 180-300 bpm
Not well tolerated
Structural abnormalities, tumors, long QT
NOT a 1:1 ratio
Ventricular Tachycardia
Management in pregnancy
NO DIGOXIN
Oral propranolol, mexiletine, sotalol,
amiodarone
Umbilical vein - lidocaine
Tachyarrhythmia
Outcomes
50% relapse after birth
Medical therapy
Neurological outcomes
Recurrence risk
Bradyarrhythmias
Differential diagnosis
Sinus bradycardia
Atrial bradycardia
Blocked atrial bigeminy
Atrial flutter with high-degree block
Complete heart block
Transient responses
Sinus Bradycardia
1:1 conduction ratio
Fetal distress
Long QT syndrome
Risk for ventricular tachycardia
Atrial bigeminy
Atria alternates sinus beats with PACs
PACs during refractory period (AV node)
Ventricular rate
Regular
½ atrial rate
Avoid caffeine, decongestants, tobacco
Atrial Flutter
Atrial rate: 300-500 BPM
High degree AV block
Results in fetal bradycardia
Constant arrhythmia
Treatment: digoxin vs sotalol
Complete Heart Block (CHB)
Most common
FHR: 40-70 bpm
Atrial rate normal
No conduction, resulting in ventricular
rate
May find 1st or 2nd degree block
Incidence: 1/20,000 live births
Complete Heart Block (CHB)
Causes
Maternal anti-Ro (SSA) or anti-La (SSB)
antibodies
Associated with SLE, Sjogren’s syndrome, connective tissue disorders
Antibodies damage fetal AV node
Suspected cofactor
20-24wga
Complete Heart Block (CHB)
Causes
Structural heart disease
L-looped ventricles
AV septal defect
Associated with polysplenia
Poor survival outcome
Complete Heart Block (CHB)
Management in pregnancy
Rheumatologic evaluation
CPS, Fetal echo
Doppler of umbilical artery (limited)
Serial growth US
Cardiothoracic ratio
NST not helpful
FHR < 60, up to twice weekly US
Complete Heart Block (CHB)
Management in pregnancy
Dexamethasone
Betamimetic agents
IVIG
Plasmapheresis
In utero heart pacing: experimental
Complete Heart Block (CHB)
Delivery
Cesarean
Consider if hemodynamic compromise
Nonimmune hydrops
Ventricular rate <55bpm
AV valve insufficiency
Pediatric cardiologist and surgeon
available
Outcomes Up to 25% develop nonimmune hydrops
15% survival
CHB with structural abnormality – poor outcome <20% survival
CHB with <55bpm 14% survival
Early delivery for pacemaker 20% survival
Neonatal lupus erythematous in 90% of SSA and SSB
90% survival after neonatal period
Plaquenil – consider in future pregnancies
References Bianci et al. (2010). Tachyarrhythmias in Fetology: Diagnosis and
Management of the Fetal Patient. McGraw Hill Medical. 313-319.
Bianci et al. (2010). Bradyarrhythmias in Fetology: Diagnosis and Management of the Fetal Patient. McGraw Hill Medical. 313-319. 320-327.
Creasy & Resnik (2009). Fetal Cardiac Malformations and Arrhythmias in Maternal Fetal Medicine Principles and Practice, 6th edition. Saunders Elsevier. 336-341.
Simpson (2006). Fetal arrhythmias. Ultrasound Obstet Gynecol. 27:599-606.
Srinivasan, Strasburger (2008). Overview of fetal arrhythmias. Current Opinions in Pediatrics. 20(5):522-531.
Strasburger, Cheulkar, Wichman (2007). Perinatal Arrhythmias: Diagnosis and Management. Clinical Perinatology. 34(4):627.