|Paper # 008||Versión en Español|
Marcial Garcia-Rojo, Carlos
Gamallo, Felipe Moreno
[Title] [Introduction] [Materials & Methods] [Results] [Picture 1] [Discussion] [Bibliography]
[Definition] [Gross] [Microscopy] [Techniques] [Other findings] [Interpretation]
The family history, does not reveal anything special(5,12,15), although in aisolated cases there was a history of contact of the mother with rubella early in the first trimester (12), diabetes and urinary tract infections during pregnancy(15).
Usually, there is no family history of a similar diseaser(2,3), although four cases have been described in two families(14,25).
They use to be children with a normal growth and development, without a previous history of serious illnesses(2,4,11,12,14,16,20,25).
Two cases suffered from corneal opacity and blindness(3,12). One of these patients, whose mother had been in contact with rubella early in the first trimester of pregnancy, was a premature child who also had grown normally, but had been found to have a soft systolic murmur at the lower left sternal border, but the cause of the murmur was not evident at necropsy. None of the other patients had previous evidence of any type of heart disease(12).
Amongst the cardiac abnomalities, in one patient a systolic murmur was found, clinically diagnosed as due to ventricular septal defect. Cardiac rhythm and conduction at that time were esentially normal, except for some left axis deviation. Subsequently the murmur became associated with a systolic thrill, but the child otherwise seemed in exellent health until her final ilness(23).
It has also been described supraventricular tachycardia at age 1 day(28 months before onset of ventricular tachycardia)(8) or in utero(8,9).
The episode of paroxysmal atrial tachycardia had ocurred two days after initial immunization with diphteria, pertussis, tetanus and oral polio(7), or smallpox(14) vaccines.
Other findings described are: mild upper-respiratory tract infection (3,8,14), viral infection (3,8) or febrile illness (3), accidental ingestion of aspirin(4), and exposure to insecticide two days before her admission(20).
One patient had been seen at the hospital several times for fever, diarrhea, bilateral otitis media, and pneumonia; on admission he had evidence of cerebral embolization(26).
One infant presented congenital cleft of the soft palate(22).
Generally the first manifestations are related to a sudden tachycardia (rapid pulse)(2,3,5,7,8,9,11,12,14,18,20,27). Other frequenly associated symptms are: vomiting(2,3,4,11,23,26.27), pallor (1,5,11,25), cyanosis(2) and irritability(5,11).
Another common manifestation is sudden death(4,13,16,17,19,24-26,28,29).
Other less frequent symptoms are diarrhea (3,23,25), sweating(25), fever (13,21,23,25), weight loss(25), Failure to thrive(15,22,25) and tachypnea(3,12,15,27).
In none case, routine pediatric examination revealed a slightly enlarged heart with no symptoms(16).
Pulse rate, though regular, is very rapid - about 300 a minute(11) or 240/min(20).
Carotid compression produced a fall in pulse rate(11), while pressure was maintained(11).
Vagal stimulation was unsuccessful(2,5,12)(In one case arrhythmias were ventricular(2) and in another junctional(5) in origin).
The first episode is followed by a second one some days(11) or a week(2) or two later(20), in one case accompanied with fever(20,8), cough(20,8), rash(8) and convulsions(20, 1,8).
After some days after withdrawal of medical treatment there was another episode of tachycardia of sudden onset(11). Every episode responds worse to treatment than the previous one(11).
Described clinical signs are:
1.- Cardiac and respiratory arrest(3).
2.- Cough(3,25), upper respiratory tract infection(3,21,8).
4.- Rapid pulse(11,2,7,27,14,3,5,12,8[11 cases]).
5.- Seriously ill(5), pale(5,25), anxious(5)
6.- Tachypnea(27,3,12). Respiratory difficulty(4,5)
8.- Letargy(3,9), drowsiness(26), loss of consciousness(20,9).
9.- Sudden death(26,4,16,13,25,24)
11.-Heart failure(tachypnea, hepatomegaly(12,15,25), peripheral edema)(12).
12.-Cleft in the palate was to be corrected, but there were difficulties at the anesthesia with halotane(22).
13.- Loss of appetite(25).
14.- Signs of hypoplastic left heart syndrome(30).
In one patient the illnesss presented as sudden death, with previuos studies for an enlarged heart, without arrhythmias, intracameral shunts or other heart alterations except a left ventricle with diminished contractility (4).
Most infants with paroxysmal atrial tachycardia do not have significant cardiac disease(14).
In those rare cases of repeated attacks of tachycardia in children which fail to respond to classical treatment, some intracardiac disease -usually a rhabdomyoma- is almost always found(11).
Biopsy of liver and skeletal muscle are useful for diagnosis. From these biopsies a storage disease can be readily excluded. Carnitine defiency is confirmed by low carnitine level in muscle and often in the blood(22). An endometrial biopsy would be helpful(22).
In infants with refractory supraventricular and ventricular dysrhythmias, study of the 12-lead ECG and 24-hour electrocardiographic tape is required to determine the type of tachycardia and considerations must be given to the causes of tachycardia at this age (cardiac tumors, myocarditis, metabolic disturbance or the present condition). If the mechanism of tachycardia cannot be determined, then detailed electrophysiologic studies, including pre- and intraoperative mapping, should be done(21).
In infants, incessant ventricular tachycardia is an entity distinct from paroxysmal ventricular tachycardia;it is most often associated with a tumor(Myocardial hamartoma or rhabdomioma) despite a "normal" echocardiogram an andiocardiogram(9).
In a review of cardiac tumors in a specialized center, myocardial hamartoma was second in prevalence only to rhabdomyoma(9)
Two possible clinical differential diagnoses are hypertrophic cardiomyopathy(8) and glucogenosis type II (Pompe's disease)(8).
The lesion is potentially accessible to surgical excision and long-term cure. Involvement of the conduction system may occur and require a pacemaker. Without surgical intervention the course appears to be rapidly fatal, so that early recognition of the characteristic clinical presentation of this benign myocardial hamartoma is essential(8).
Generally, it presents as a sudden supraventricular tachycardia supraventricular (250 - 320 beats per minute) with a regular rythm(2,3,7,11,14,26).
1.- Supraventricular (paroxysmal junctional(5)) tachycardia(2, 7,26,3,23,12,9,25)
1a.- with aberrant intraventricular conduction(3,5,9).
1b.- with right bundle branch block(3,5).
1c.- with left posterior hemiblock(5).
1d.- with retrograde conduction to the atrial 1:1 or 1:2.
2.- Paroxysmal atrial tachycardia(11,14) or atrial flutter(240/min)(1).
3.- Ventricular tachycardia(20,7,27,8[11 cases]).
4.- Premature ventricular beats(23,4) and bigeminy(4)
5.- Hypertrophy of the left ventricle, a pathological Q profile and a S-T abnormality(22,15) and short PR interval(15).
6.- Ventricular fibrillation(21).
7.- Cardiac arrest(26,3).
Sudden onset of supraventricular tachycardia(300-320/min) (11,2,7,26,14,3) at a regular rate of 300(11)-320(2) a minute, sometimes with a right bundle branch block(11,26) or an aberrant intraventricular conduction(3).
Ventricular bigeminy followed by tachycardia(2), and 10 days later multifocal premature ventricular contractions, with occasional bigeminal or trigeminal pattern reappeared, with a sinus rhythm(2).
Some days later multiple premature ventricular contractions appeared(2), or they may be the first arrhythmia detected(20).
Premature ventricular or junctional beats(20,23) and repetitive episodes of ventricular functional tachycardia(20).Two weeks later she showed bursts of supraventricular tachycardia and bouts of ventricular tachycardia(240-260/m)(20).
Intermitent A-V dissociation and chaotic multifocal intermittent arrhythmias(23).
It may be normal(2) o show a slight (8) or masive(15) cardiomegaly.
Cardiac catheterization and angiography:
- Normal(2) or reduced left ventricular function(9,21).
- Non obstructive hypertrophy of the left ventricle(22).
- Hypertrophy of both ventricles and the ventricular septum with diminished contractility (8).
- Decreased left ventricular function(8,9).
- No structural abnormalities (9).
Localization of arrhythmogenic areas(9,10,21): Apex of left ventricle(9).
- Within normal limits(2).
- Negative cultures and viral studies(4,20,30).
- Negative studies for heavy metals (cadmium, cobalt, chromium, copper, iron, nickel, tin, zinc, lead)(2).
- Supraventricular tachycardia of 300 beats per minute
à Sinusal rythm with A-V block à Ventricular fibrillation à Cardiac arrest(3).
à Sinusal rythm à Supraventricular tachycardia à Ventricular fibrillationà Death(12).
à Bradycardia à Cardiac arrest à Surgery à Cerebral death(22).
à Cardiorrespiratory arrest(11).
à Premature ventricular contractionsà A-V Dissociation à Ventricular fibrillationà Death(2).
à Abnormal conduction à Ventricular fibrillationà Ventricular tachycardia(9).
- Bursts of supraventricular tachycardia and bouts of ventricular tachycardia(240-260/m)(20).
- Premature ventricular beats with/without bigeminism
à Ventricular and supraventricular tachycardia à Ventricular fibrillation à Death(20).
à Sudden death(4).
- Paroxysmal atrial tachycardia(PAT) à Preexitation(classical form of Wolff-Parkinson-White syndrome) à PAT à Ventricular fibrillation à bradycardia with ventricular bigeminyà junctional tachycardia with premature ventricular contractions à PAT à ventricular fibrillation à PTA + premature ventricular beats + brief asystole à ventricular fibrillation à pace maker à ventricular fibrillation à death(14).
- Cardiorrespiratory arrest à Resuscitation à bouts of ventricular and supraventricular tachycardia à Cardiac arrestà Death(3,11,18).
- Paroxysmal junctional tachycardia(300/m) with anomalous intraverntricular pathway and retrograde conduction--sinus rhythm spontaneouslyà sudden ventricular fibrillation à death(5).
- Ventricular fibrillationà resuscitation à ventricular and supraventricular arrhythmias with attacks of ventricular fibrillation à asystolic cardiac arrests à generalized convulsions(21).
- Ventricular tachycardia and cardiac arrest, seizures or ventricular fibrillation(8).
Digitalis and sedatives made the pulse rate fell(11,2,12), and in some cases sinus rhythm is restored after some hours(2,14,12). After some days she suffered further attacks that were successfully treated with quinidine, but with increasing doses(11).
Ventricular arrhythmias responded to propanolol(2)
Tachycardia at a rate of 320 per minute was treated unsuccessfully with propanolol and required electrical cardioversion(2).
Procainamide reverted ventricular tachycardia to sinus rhythm only temporarily(20), and the same happened despite quinidine and digoxin therapy.
At various times arrythmias either responded only temporarily or nor at all to digoxin, propranolol, diphenyldantoin sodium, furosemide, quinidine, potassium, and electrical countershock(23).
Pharmacological treatment was ineffective (from the start) and ten hours after its onset the arrhythmia subsided spontaneously(5).
Tachycardia responded to digoxin and 11 weeks later tachycardia failed to respond to propranolol(12).
No improvement with digoxin, lidocaine, quinidine, propranolol, phenytoin, atropine, disopyramide and corticosteroids in many combinations and dosages(21).
Attempts to overdrive and capture the cardiac rhythm with pacemaker were unsuccessful(14,23).
The lesion is potentially accessible to surgical excision and long-term cure. Involvement of the conduction system may occur and require a pacemaker.
Some of the surgical interventions described are:
- Production of permanent heart block surgically (the region of the atrioventricular node was cauterized) at the same time the ventricular septal defect could be closed, and then to rely on permanent electronic pacing(21,23).
- Endomyocardial biopsy(8,21,32,33,34). A biopsy was done of a fibrous thickening of the endocardium of the left ventricle(21), or removal of an yellowish area in the lower part of the membranous ventricular septum(24).
Nine of 11 patients who underwent electrophysiologic mapping and surgical excision of the lesion have survived and improved ventricular function(8).
One infant died during cardiac surgery for signs of hypoplastic left heart syndrome(30)