Initial results of primary device closure of large muscular ventricular septal defects in early infancy using perventricular access.

OBJECTIVES: To report our experience with the use of the Amplatzer muscular ventricular septal defect (VSD) occluder, using direct right ventricle free wall puncture for primary closure of muscular VSDs in infants. BACKGROUND: Young infants with heart failure due to large or multiple muscular VSDs often require intervention at a stage when percutaneous device closure is impractical due to delivery system limitations. There are considerable benefits to avoiding bypass in these infants. METHODS: Patients with suitable muscular VSDs, considered too small for transvenous closure, underwent periventricular muscular VSD closure under transesophageal echo (TEE) guidance. RESULTS: Eight infants underwent the procedure. The median age was 14 weeks (2-41) with median weight of 4 kg (3-6.6). Four patients had additional VSDs and one patient had previous repair of coarctation. One patient had dextrocardia and severe left ventricular impairment due to an associated cardiomyopathy. The median VSD size was 8 mm (range, 4-10 mm). A single device (6-12 mm) was deployed in each patient, the size chosen being 1-2 mm larger than the TEE measurement. Two patients had subsequent pulmonary artery banding, with absorbable bands, because of moderate residual shunting through additional VSDs. The latest echo study at a median of 7.2 weeks (0.5-66) post device implantation revealed no patients with a hemodynamically significant shunt. CONCLUSION: Perventricular muscular VSD closure can be safely and effectively undertaken in small infants with suitable muscular defects, and this strategy can avoid the need for bypass.

Percutaneous coil occlusion of ascending aorta to pulmonary artery shunts.

Two patients with pulmonary atresia and intact ventricular septum each underwent early palliative surgery with a pulmonary valvotomy and an ascending aorta to pulmonary artery shunt. Adequate right ventricular growth and relief of pulmonary stenosis rendered the shunts unnecessary. The shunts were successfully occluded percutaneously with Gianturco coils.

Myocardial hibernation identified by hyperbaric oxygen treatment and echocardiography in postinfarction patients: comparison with exercise thallium scintigraphy.

To evaluate the potential for hyperbaric oxygen (HBO) to produce transient improvement in function in areas of myocardium ischemic at rest (hibernating myocardium), 24 patients were studied within 1 week of acute myocardial infarction. Results were compared with single-photon emission computed tomography (SPECT) thallium-201 exercise scintigraphy. Echocardiography demonstrated improved contraction following HBO in 20 of 62 damaged left ventricular segments in 12 of 24 patients. Thirteen of the 28 segments and 9 of the 14 patients showing reversible ischemia on SPECT imaging showed improvement with HBO. There were eight segments with apparently normal resting contraction that showed a reversible thallium defect. Of 42 segments with fixed contraction abnormalities following HBO, eight had reversible thallium defects, four had normal thallium kinetics, and 30 had fixed thallium defects. Thus hyperbaric oxygen can demonstrate improvement in function in some segments of left ventricle after infarction. There is some overlap with viability as determined by thallium studies, but the two techniques may be complementary in describing myocardial ischemia.

Congenital syphilis has not disappeared.

Thirty-three cases of congenital syphilis that were seen at The Children's Hospital, Camperdown, over a 34-year period were reviewed. Twenty-nine cases were examples of early congenital syphilis, as the patients developed clinical features in the first two years of life, and the other four cases were examples of late congenital syphilis, with the clinical features developing between two years and nine months of age and 10 years of age. Twenty-five patients were symptomatic at the time of admission to hospital. The most common clinical feature on the patient's presentation to hospital was a maculopapular or vesiculobullous skin eruption which occurred in 13 of the infants. Hepatic and splenic enlargement were present in 12 cases, and nine children had the "snuffles". Five of the children died. Patient follow-up occurred in fewer than 40% of cases and three of the children who were followed-up suffer from developmental delay. Congenital syphilis can occur in all social groups but is most common in infants who are premature or are small for gestational age and are born to young, unmarried mothers of low socioeconomic status. The treatment of congenital syphilis is simple and effective although the patients may need to be linked with community-health facilities to assist in their compliance with follow-up appointments.

The relationship between angiographic findings and risk factors in young men with myocardial infarction.

Coronary angiography was performed and risk factors were evaluated 2-4 months after myocardial infarction in 50 men aged 40 years or less. There was a high incidence of heavy cigarette smoking, obesity and hyperlipidaemia among these young men. Single-vessel disease (greater than or equal to 70% coronary obstruction) was found in 52%, double-vessel disease in 22% and triple-vessel disease in 20%, the right coronary artery being more frequently involved (greater than or equal to 70% obstructed) or totally occluded than the left anterior descending or left circumflex coronary arteries, in that order. One of the 2 patients with a normal coronary arteriogram had left ventricular angiographic evidence of previous infarction. There was no apparent difference in the distribution of coronary artery disease in this group of young men from the reported distribution found in older subjects. Neither was there any significant correlation of any single major coronary risk factor or combination thereof with the extent or severity of coronary artery obstruction.

Failure to recognize a His bundle potential in complete atrioventricular block.

This report concerns a patient with complete heart block, in whom electrophysiological studies showed at times an escape rhythm with narrow QRS complexes preceded by His potentials with normal HV intervals (35--40 msec) and at other times an escape rhythm of similar rate, having wide QRS complexes of left bundle branch block configuration with no preceding His bundle activity. Complexes intermediate in width and configuration and preceded by His potentials with an HV interval inversely proportional to QRS width were also recorded. These observations are explained by a site of block proximal to the His bundle and competition between two pacemaker foci having similar discharge rates, one situated in the junctional region below the site of block and the other more distally in the right bundle branch or right ventricle. It is proposed that the combination of a proximal site of block and a distally situated dominant pacemaker may be a common reason for failure to record a His potential in patients with complete heart block.

Ventricular overdrive suppression of idioventricular rhythm in patients with complete heart block.

Idioventricular rate, QRS width, site of block and responses to ventricular overdrive pacing were studied in 29 patients with chronic complete heart block in an attempt to distinguish patients liable to syncopal attacks. Ten patients were asymptomatic, 5 gave a history of presyncope and 14 of syncope. Although the mean idioventricular rate of the 10 patients in the narrow QRS group (40.0 per min) was significantly faster than that of the 19 patients in the wide QRS group (35.5 per min; P less than 0.02), the rate did not distinguish symptomatic patients in either the narrow or the wide QRS groups. His bundle studies of the site of block were also unhelpful. Overdrive right ventricular pacing at increasing rates was used to assess ventricular escape times which were not significantly different in symptomatic and asymptomatic wide QRS patients. There was, however, a significant difference in the product of maximum ventricular escape time X overdrive cycle length between symptomatic and asymptomatic narrow QRS patients after 30 s overdrive (3.850+/-1.670 vs 1.070+/-0.475; P less than 0.01); 60 s overdrive (5.020+/-2.170 vs 1.240+/-0.515; P less than 0.01) and 120 s overdrive (6.040+/-2.900 vs 1.460+/-0.275; P less than 0.01) which may have clinical predictive values.

Effect of ventricular extrasystoles on idioventricular rhythm in patients with complete heart block.

Idioventricular rate, QRS width, site of block and responses to premature ventricular stimulation were studied in 23 patients with chronic complete heart block in an attempt to distinguish patients liable to syncopal attacks. Seven patients were asymptomatic, five gave a history of presyncope and 11 of syncope. Although the mean idioventricular rate of the nine patients in the narrow QRS group (39.7 per min) was significantly faster than that of the 14 patients in the wide QRS group (35.3 per min; P less than 0.05), the rate did not distinguish symptomatic patients within either the narrow or the wide QRS groups. His bundle studies of the site of block and the effect of single and paired right ventricular stimulation upon idioventricular rhythm were also unhelpful. The response of the return cycle to increasingly premature ventricular extrasystoles, however, proved more complex than was anticipated.

Electrophysiological studies in four patients with atrial flutter with 1:1 atrioventricular conduction.

Electrophysiological studies of atrioventricular conduction during rapid atrial overdrive pacing and during programmed premature atrial stimulation are reported in four patients with an unusually rapid 1:1 ventricular response to atrial flutter (ventricular rates 240 to 310 per minute). Second-degree AV block development during atrial overdrive pacing at rates well below those during spontaneous atrial flutter. Although none of the four patients showed evidence of pre-excitation on the standard 12-lead electrocardiogram, evidence suggesting a partial AV nodal bypass was demonstrated at electrophysiological study in one case. It is postulated that the profile of the atrial wavefront presented to the normal AV node by atrial flutter differs from that during high right atrial pacing and may account for the lower ventricular rates achieved during high right atrial overdrive pacing than during spontaneous atrial flutter in the remaining three cases.

Myocardial infarction--the problems and prognosis: Paper 3--A summary.

In the pre-hospital phase of myocardial infarction, the overriding problem is our present inability to alter the fact that approximately 50 per cent of all deaths from infarction occur prior to the patient's arrival in hospital, despite the knowledge that these deaths are due largely to potentially correctible arrythmias.