12/17/2010

Surgery: L-TGA with Pulm. Atresia, Alternative Surgical Option


An alternative approach to the surgical management of physiologically corrected transposition with VSD and PS or P.atresia. Ilbawi, MN, et al. JTCVS 1990;100:410-5



12/03/2010

EKG - Interpret this...

Pardon the baseline artifacts

Anatomy: IVC variations


Systemic veins develop from 3 main venous systems:
1) Vitelline venous system (Yellow)
2) Umbilical venous system (Red)
3) Cardinal venous system (Blue) - Anterior (SVC side), Posterior (IVC side)

Others:
Subcardinal veins - Green
Sacrocardinal vein - Purple
Hepatocardinal channel - Orange

Anatomy: Persistent LSVC


Anatomy: Netter - IVC - Development





















11/12/2010

ICU: EKG strip

Importance of examining a long-enough strip:

Diagnosis changes once you look at the lower panel.

What is the diagnosis for the upper panel?

What is the diagnosis for the lower panel?

ICU: EKG strip. Interpret this...

Interpret this.
3 yr old child
Modified Konno Procedure
Immediate postop.

11/10/2010

EKG - Misplaced Leads.

4 week old baby s/p Coil occlusion for Vein of Galen malformation.
Note: Baby does not have dextrocardia.



For comparison, this is the baby's earlier EKG at 3 days of age.

10/23/2010

Echo: Vein of Galen Malformation

Dabigatran - Alternative for Warfarin

RE-LY trial in patients with Atrial fibrillation.
Dabigatran was approved by FDA on 10/20/10.
See the posting on Journal Club.

Anti-platelet agents...to be expanded further.

Antiplatelet drugs alter the platelet activation at the site of vascular damage crucial to the development of arterial thrombosis.

Aspirin
irreversibly inhibits the enzyme COX, resulting in reduced platelet production of TXA2 (thromboxane - powerful vasoconstrictor which lowers cyclic AMP and initiates the platelet release reaction).

Dipyridamole
inhibits platelet phosphodiesterase, causing an increase in cyclic AMP with potentiation of the action of PGI2 – opposes actions of TXA2

Clopidogrel
affects the ADP-dependent activation of IIb/IIIa complex

Glycoprotein IIb/IIIa receptor antagonists block a receptor on the platelet for fibrinogen and von Willebrand factor. 3 classes:
Murine-human chimeric antibodies (e.g. abciximab)
Synthetic peptides (e.g. eptifibatide)
Synthetic non-peptides (e.g. tirofiban)

10/14/2010

EKG: Interpret this...

2 yr old, postop. VSD. Returned from operating room 2 hrs ago.
What is the rhythm?
Where are the P waves?
Just a little help to identify P waves: Atrial lead is connected in V1.

Atrial Lead is connected in V1, now recorded at 50 mm/sec paper speed - to help with identifying P waves:




10/13/2010

EKG: Interpret this, Learn Ladder Diagram

What is happening after the PVC?
Originally posted by
Dr Kyuhyun Wang, Clinical Professor of Medicine, University of Minnesota, Minneapolis, MN.
Link to the original article in HeartWire: http://www.theheart.org/article/1130549.do

10/05/2010

EKG: Low Voltage Complexes & Lead Misplacement

Low voltage complexes. Cause of this is evident in the CXR below.

What is the P wave axis? What will be the diagnosis for the unusual P wave axis?

If unusual P wave axis were to be due to misplacement of leads, which leads were misplaced?

If certain leads were misplaced...what would be the QRS axis, if the misplaced leads were








10/01/2010

What is the mistake?

Infant, s/p Repair of AVSD (Postop. day 8)
Postoperative Heart Block
Temporary pacemaker setting: DDD @ 90 bpm.
What is the mistake made by the nurse? (or the resident, or the fellow...attending would not have done it!!)



9/13/2010

EKG: Interpret this...

From a Holter recording, in a 3 week old neonate.


8/12/2010

ICU: Glycopyrrolate

Source: rxlist.com

Quarternary Ammonium Compound.

"Does not" cross blood brain barrier. Therefore, CNS side effects will be relatively milder.

Dose:
1) Preanesthetic Medication.
In pediatric patients is 0.004 mg/kg IM, given 30 to 60 minutes prior to induction or at the time the preanesthetic narcotic and/or sedative are administered.
Infants.
(1 month to 2 years of age) may require up to 0.009 mg/kg.
2) Intraoperative Medication.
Because of the long duration of action of Robinul Injection if used as preanesthetic medication, additional Robinul Injection for anticholinergic effect intraoperatively is rarely needed; in the event it is required the recommended pediatric dose is 0.004 mg/kg intravenously, not to exceed 0.1 mg in a single dose which may be repeated, as needed, at intervals of 2 to 3 minutes. The usual attempts should be made to determine the etiology of the arrhythmia, and the surgical or anesthetic manipulations necessary to correct parasympathetic imbalance should be performed.
3) Reversal of Neuromuscular Blockade.
The recommended pediatric dose of Robinul Injection is 0.2 mg for each 1.0 mg of neostigmine or 5.0 mg of pyridostigmine. In order to minimize the appearance of cardiac side effects, the drugs may be administered simultaneously by intravenous injection and may be mixed in the same syringe.
4) Peptic Ulcer.
Robinul Injection is not recommended for the treatment of peptic ulcer in pediatric patients (see PRECAUTIONS - Pediatric Use)

Side effects:
Anticholinergics, including Robinul Injection, can produce certain effects, most of which are extensions of their pharmacologic actions. Adverse reactions may include xerostomia (dry mouth); urinary hesitancy and retention; blurred vision and photophobia due to mydriasis (dilation of the pupil); cycloplegia; increased ocular tension; tachycardia; palpitation; decreased sweating; loss of taste; headache; nervousness; drowsiness; weakness; dizziness; insomnia; nausea; vomiting; impotence; suppression of lactation; constipation; bloated feeling; severe allergic reactions including anaphylactic/anaphylactoid reactions; hypersensitivity; urticaria, pruritus, dry skin, and other dermal manifestations; some degree of mental confusion and/or excitement, especially in elderly persons.
In addition, the following adverse events have been reported from post-marketing experience with Robinul: malignant hyperthermia; cardiac arrhythmias (including bradycardia, ventricular tachycardia, ventricular fibrillation); cardiac arrest; hypertension; hypotension; seizures; and respiratory arrest. Post-marketing reports have included cases of heart block and QTc interval prolongation associated with the combined use of glycopyrrolate and an anticholinesterase. Injection site reactions including pruritus, edema, erythema, and pain have also been reported.
Robinul is chemically a quaternary ammonium compound; hence, its passage across lipid membranes, such as the blood-brain barrier is limited in contrast to atropine sulfate and scopolamine hydrobromide. For this reason the occurrence of CNS-related side effects is lower, in comparison to their incidence following administration of anticholinergics which are chemically tertiary amines that can cross this barrier readily.

Drug Interactions:
The concurrent use with other anticholinergics, such as phenothiazines, antiparkinson drugs, or tricyclic antidepressants, may intensify the antimuscarinic, anticholinergic effects.

Overdose treatment:
To combat peripheral anticholinergic effects, a quaternary ammonium anticholinesterase such as neostigmine methylsulfate (which does not cross the blood-brain barrier) may be given intravenously in increments of 0.25 mg in adults. This dosage may be repeated every five to ten minutes until anticholinergic overactivity is reversed or up to a maximum of 2.5 mg. Proportionately smaller doses should be used in pediatric patients. Indication for repetitive doses of neostigmine should be based on close monitoring of the decrease in heart rate and the return of bowel sounds.
If CNS symptoms (e.g., excitement, restlessness, convulsions, psychotic behavior) occur, physostigmine (which does cross the blood-brain barrier) may be used. Physostigmine 0.5 to 2 mg should be slowly administered intravenously and repeated as necessary up to a total of 5 mg in adults. Proportionately smaller doses should be used in pediatric patients.
To combat hypotension, administer IV fluids and/or pressor agents along with supportive care.
Fever should be treated symptomatically.
Following overdosage, a curare-like action may occur, i.e., neuromuscular blockade leading to muscular weakness and possible paralysis. In the event of a curare-like effect on respiratory muscles, artificial respiration should be instituted and maintained until effective respiratory action returns.

Contraindication:
1) Known hypersensitivity to glycopyrrolate or any of its inactive ingredients.
2) In addition, in the management of peptic ulcer patients, because of the longer duration of therapy, Robinul Injection may be contraindicated in patients with the following concurrent conditions: glaucoma; obstructive uropathy (for example, bladder neck obstruction due to prostatic hypertrophy); obstructive disease of the gastrointestinal tract (as in achalasia, pyloroduodenal stenosis, etc.); paralytic ileus, intestinal atony of the elderly or debilitated patient; unstable cardiovascular status in acute hemorrhage; severe ulcerative colitis; toxic megacolon complicating ulcerative colitis; myasthenia gravis.


Precautions:
This drug should be used with great caution, if at all, in patients with glaucoma.
Exposure to excessive amounts of benzyl alcohol has been associated with toxicity (hypotension, metabolic acidosis), particularly in neonates, and an increased incidence of kernicterus, particularly in small preterm infants. There have been rare reports of deaths, primarily in preterm infants, associated with exposure to excessive amounts of benzyl alcohol. The amount of benzyl alcohol from medications is usually considered negligible compared to that received in flush solutions containing benzyl alcohol. Administration of high dosages of medications containing this preservative must take into account the total amount of benzyl alcohol administered. The amount of benzyl alcohol at which toxicity may occur is not known. If the patient requires more than the recommended dosages or other medications containing this preservative, the practitioner must consider the daily metabolic load of benzyl alcohol from these combined sources. (see PRECAUTIONS, Pediatric Use).
Robinul Injection may produce drowsiness or blurred vision. The patient should be cautioned regarding activities requiring mental alertness such as operating a motor vehicle or other machinery or performing hazardous work while taking this drug.
In addition, in the presence of fever, high environmental temperature and/or during physical exercise, heat prostration can occur with use of anticholinergic agents including glycopyrrolate (due to decreased sweating), particularly in children and the elderly.
Diarrhea may be an early symptom of incomplete intestinal obstruction, especially in patients with ileostomy or colostomy. In this instance treatment with Robinul Injection would be inappropriate and possibly harmful.

General Precautions:
Investigate any tachycardia before giving Robinul Injection since an increase in the heart rate may occur.

Use with caution in patients with: coronary artery disease; congestive heart failure; cardiac arrhythmias; hypertension; hyperthyroidism.

Use with caution in patients with renal disease since the renal elimination of glycopyrrolate may be severely impaired in patients with renal failure. Dosage adjustments may be necessary (see Pharmacokinetics - Renally Impaired).

Use Robinul with caution in the elderly and in all patients with autonomic neuropathy, hepatic disease, ulcerative colitis, prostic hypertrophy, or hiatal hernia, since anticholinergic drugs may aggravate these conditions.

The use of anticholinergetic drugs in the treatment of gastric ulcer may produce a delay in gastric emptying due to antral statis.

Carcinogenesis, Mutagenesis, Impairment Of Fertility
Long-term studies in animals have not been performed to evaluate carcinogenic potential. Studies to evaluate the mutagenic potential of glycopyrrolate have not been conducted. In reproduction studies in rats, dietary administration of glycopyrrolate resulted in diminished rates of conception in a dose- related manner. Other studies in dogs suggest that this may be due to diminished seminal secretion which is evident at high doses of glycopyrrolate.

Pregnancy: Teratogenic Effects - Pregnancy Category B.
Reproduction studies with glycopyrrolate were performed in rats at a dietary dose of approximately 65 mg/kg/day (exposure was approximately 320 times the maximum recommended daily human dose of 2 mg on a mg/m2 basis) and rabbits at intramuscular doses of up to 0.5 mg/kg/day (exposure was approximately 5 times the maximum recommended daily human dose on a mg/m2 basis). These studies produced no teratogenic effects to the fetus. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
Single-dose studies in humans found that very small amounts of glycopyrrolate passed the placental barrier.

PregnancyL Nonteratogenic effects
Published literature suggest the following regarding the use of glycopyrrolate during pregnancy. Unlike atropine, glycopyrrolate in normal doses (0.004 mg/kg) does not appear to affect fetal heart rate or fetal heart rate variability to a significant degree. Concentrations of glycopyrrolate in umbilical venous and aterial blood and in the amniotic fluid are low after intramuscular administration to parturients. Therefore, glycopyrrolate does not appear to penetrate through the placental barrier in significant amounts. In reproduction studies in rats, dietary administration of glycopyrrolate resulted in diminished rats of pup survival in a dose-related manner.

Nursing Mothers
It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when Robinul Injection is administered to a nursing woman. As with other anticholinergics, glycopyrrolate may cause suppression of lactation (see ADVERSE REACTIONS).

Pediatric Use
Due to its benzyl alcohol content, Robinul Injection should not be used in neonates, i.e., patients less than 1 month of age.

Safety and effectiveness in pediatric patients below the age of 16 years have not been established.

Safety and effectiveness in pediatric patients have not been established for the management of peptic ulcer.

Dysrhythmias associated with the use of glycopyrrolate intravenously as a premedicant or during anesthesia have been observed in pediatric patients.

Infants, patients with Down's syndrome, and pediatric patients with spastic paralysis or brain damage may experience an increased response to anticholinergics, thus increasing the potential for side effects.

A paradoxical reaction characterized by hyperexcitability may occur in pediatric patients taking large doses of anticholinergics including Robinul Injection. Infants and young children are especially susceptible to the toxic effects of anticholinergics.

Benzyl alcohol, a component of this drug product, has been associated with serious adverse events and death, particularly in pediatric patients. The "gasping syndrome," (characterized by central nervous system depression, metabolic acidosis, gasping respirations, and high levels of benzyl alcohol and its metabolites found in the blood and urine) has been associated with benzyl alcohol dosages > 99 mg/kg/day in neonates and low-birth-weight neonates. Additional symptoms may include gradual neurological deterioration, seizures, intracranial hemorrhage, hemotologic abnormalities, skin breakdown, hepatic and renal failure, hypotension, bradycardia, and cardiovascular collapse. Although normal therapeutic doses of this product deliver amounts of benzyl alcohol that are substantially lower than those reported in association with the "gasping syndrome," the minimum amount of benzyl alcohol at which toxicity may occur is not known. Premature and low-birthweight infants, as well as patients receiving high dosages, may be more likely to develop toxicity. Practitioners administering this and other medications containing benzyl alcohol should consider the combined daily metabolic load of benzyl alcohol from all sources.

Geriatric Use
Clinical Studies of Robinul Injection did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting a the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other therapy

Re: Acetyl Choline receptors
Two type: muscarinic and nicotinic
Muscarinic - has parasympathetic effect on the secretory exocrine glands & smooth and cardiac muscles. ?Pupils too.
Nicotinic - has effect on skeletal (voluntary) muscles; not part of autonomic nervous system.

8/11/2010

ICU/EKG: Junctional Rhythm, Atrial lead EKG

Rhythm strip from Surface Leads:

What is the rhythm? Atrial lead is on V1.
How would you differentiate between Sinus rhythm with First degree AV block from Junctional rhythm with retrograde P, in this patient? (14 month old, s/p TOF repair, Postop day #1)



ICU: Monitor, A-pace, AV-pace, CVP trace

14 mo old, s/p TOF repair, POD#1
Accelerated junctional rhythm around 130
? First degree AV block upon A-pacing
AV-pacing is shown in lower panel.
Note: CVP trace and BP difference between the two panels.


8/06/2010

ICU; EKG - What's the rhythm?

10 day old, s/p Repair of IAA/VSD, Postop. day #7:
(Click on the image to see a larger version)

Cath: Coil occlusion of collateral vessels - Coil size selection

Image from "Diagnostic and Interventional Catheterization in Congenital Heart Disease" Lock, Keane & Perry. 2nd ed. 2000 (p.205). Kluwer Academic Publishers.

Radiograph of tubes of different sizes ranging from 5 mm - 10 mm, with a 10 mm coil inside each:

8/05/2010

Ventricular ectopy

How would you differentiate atrial ectopy from ventricular ectopy?
What is compensatory pause?

Atrial Ectopy

6 year old with incidental finding of irregular heart rate during routine physical exam.

Why is the PR interval prolonged in the ectopic beats?
Why is the QRS morphology variable?

Radial A line trace...why is it like that?!

This is a newborn baby with PA-VSD, MAPCAs.
Postop day#2 after RVOT patch (transannular).
Generally, doing well.




And, one day later...the same arterial line trace looks like this!!!




Possible explanations: (i) Papaverine was started or (ii) Tubing for the transducer was changed to a rigid, "pressure-tubing" (from a more compliant, "non-pressure" tubing).


This improvement in waveform may also occur when the arterial catheter is changed to a larger caliber.


Description & study of the above distortion in arterial line is illustrated below:

(From Cardiovascular Dynamics by Robert F. Rushmer MD. 3rd ed.1970. W.B.Saunders. page 162)

8/01/2010

Junctional Ectopic Tachycardia

Interrupted aortic arch and VSD repair
Newborn.
Day of Surgery:
Postop. day 1:
Postop. day 2:



7/28/2010

Persistent fifth arch

Dr. Thapar's patient from 1991:
Persistent fifth arch with Coarctation and TOF.






Images in Pediatric Cardiology:

Non-invasive Imaging of Isolated Persistent Fifth Aortic Arch.
SG Yang, et al. Pediatr Cardiol 2003;24:179-81.