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Biomedical subjects

J C Shelburne

Publications and source records attributed to J C Shelburne.

At least 19 recordsLinked to original sources
PubMed1979

Clinical and physiological findings when the cardiac contraction is incoordinate compared with those found in matched cases with well-coordinated hearts.

A group of patients in whom the Bcg, the pulse derivative and the ventriculogram all agreed that cardiac incoordination was present has been compared with another group in which the same three tests agreed that the heartbeat was well coordinated. By pairing the cases we have demonstrated that those with cardiac incoordination showed significantly more angina pectoris, more coronary arteriosclerosis, more abnormal electrocardiograms, a slowed pulse rate and a smaller ejection fraction than did the corresponding cases. The other physiological functions measured were not significantly different in the two groups. Evidently, incoordination of the cardiac contraction is associated with other evidences of severe coronary heart disease. One can regard it as the physiological consequences of the irregular interruptions of coronary blood supply which characterize the pathological anatomy of this disease, and can expect it to appear late in its course.

Ballistocardiography↗
PubMed1977

"Acute" granulomatous pericarditis. clinical and hemodynamic correlate.

Ten cases of acute constrictive pericarditis from southern Iran are presented. They differed from chronic constrictive pericarditis by the absence of ascutes and edema of the lower extremities, the presence of cardiomegaly on posteroanterior chest x-ray film, the lack of calcification of the pericardium on fluoroscopic examination, and the presence of sinus rhythm in all cases. If tuberculosis is the etiologic agent, early pericardiectomy should be considered. This is especially important in areas where close follow-up of patients is difficult or impossible, since all patients in this series ultimately developed clinically significant constriction.

Adolescent↗
PubMed1976

Isolated dextroversion of the heart with asymmetric septal hypertrophy.

Dextroversion of the heart is an uncommon congenital anomaly characterized by situs solitus (normal position) of thoracic and abdominal viscera with right cardiac apex. Isolated dextroversion, i.e., without associated congenital heart disease, is rare, but its occurrence permits adult survival, setting the stage for late development of acquired heart disease. The patient herein reported was known since childhood to have a right thoracic heart that represented isolated uncomplicated dextroversion. He presented in the sixth decade with a new murmur that proved to be due to asymmetric septal hypertrophy (ASH) with obstruction. This combination of anomalies is possible only if dextroversion exists without ventricular inversion, since aortic-anterior mitral leaflet continuity is obligatory for obstructive ASH. This paper presented clinical, phonocardiographic, vectorcardiographic, echocardiographic, hemodynamic, angiocardiographic, and intracardiac electrophysiologic information on the unique combination of isolated dextroversion of the heart with obstructive asymmetric septal hypertrophy.

Cardiomegaly↗
PubMed1976

A comparison of three methods of detecting ventricular incoordination in man, and the relation of their results to the amount of coronary arteriosclerosis.

The results secured by three tests for cardiac incoordination have been compared in over 100 cardiac cases. The Bcg found the abnormality more frequently than did Vgm and PDmax, the probable reasons for this are discussed. The cases in which cardiac incoordination was detected showed, on the average, more coronary arteriosclerosis than those whose hearts beat normally.

Adult↗
PubMed1975

Intraventricular conduction in man studied with an endocardial electrode catheter mapping technique. Patients with normal QRS and right bundle branch block.

The sequence of intraventricular conduction has been studied in a total of 60 patients, 38 of whom had normal QRS morphology and 37 of whom had right bundle branch block (RBBB) either present continuously or produced as functional aberrant RBBB by the introduction of atrial premature depolarizations or by rapid atrial pacing. Activation times were measured by intracardiac electrode catheters positioned at the right ventricular inflow tract (RVIT), right ventricular apex (RVA), right ventricular outflow tract (RVOT), left ventricular apex (LVA) and left ventricular outflow tract (LVOT). The activation after beginning of QRS in milliseconds plus or minus 1 SD and the number of patients studied at each location were: RVIT--normal 23 plus or minus 13 (15 patients); RVIT-RBBB 49 plus or minus 16 (15 patients); RVA--normal 18 plus or minus 9 (28 patients); RVA-RBBB 54 plus or minus 16 (30 patients); RVOT--normal 40 plus or minus 10 (28 patients); RVOT-RBBB 78 plus or minus 21 (30 patients);LVA--normal 9 plus or minus 9 (18 patients); LVA-RBBB 6 plus or minus 10 (10 patients); LVOT--normal 45 plus or minus 13 (10 patients); LVOT-RBBB 32 plus or minus 9 (7 patients). Significant differences observed were: RVA-normal versus RVA-RBBB P smaller than 0.001; RVOT-RBBB P smaller than 0.001; RVA-normal versus LVA-normal P smaller than 0.005; LVA-normal versus LVA-RBBB NS, LVOT-normal versus LVOT-RBBB P smaller than 0.05. The LVOT change was unexpected and suggests changes in left ventricular depolarization may occur when right bundle branch block develops. In patients with RBBB the activation of the RVA (r equals 0.82) and of the RVOT (r equals 0.68) was directly related to the duration of QRS. Changes in activation time when RBBB was induced by rapid atrial pacing or by introduction of atrial premature depolarizations were: RVA (7 patients) 19 plus or minus 11 to 56 plus or minus 16 (P smaller than 0.001); RVOT (9 patients) 41 plus or minus 10 to 77 plus or minus 22 (P SMALLER THAN 0.001); LVA (5 patients) and LVOT (2 patients), small insignigicant changes. These data indicate that endocardial activation changes can be evaluated in the catheterization laboratory, that right ventricular conduction becomes slower in RBBB as a direct function of total QRS and that left ventricular conduction may be affected when RBBB develops.

Action Potentials↗
PubMed1975

Electrophysiologic characteristics of Ebstein's anomaly of the tricuspid valve.

Electrophysiologic characteristics of five patients with Ebstein's anomaly of the tricuspid valve were defined with studies using luminal intracardiac electrode catheters. The diagnosis was made in each case from clinical data and confirmed at cardiac catheterization by the presence of an atrialized right ventricular chamber with atrial mechanical activity and ventricular electrical activity. In three cases intra-right atrial conduction was prolonged (P-A intervals of 50, 50, and 65 msec), a finding which reflected the presence of a characteristically large right atrium. The bundle of His electrogram was recorded in its usual anatomical location. Atrioventricular nodal conduction was prolonged in only one case. Intra-His delay was observed in two cases (bundle of His duration of 30 and 30 msec). Infranodal conduction was prolonged in four cases with H-V intervals of 60, 65, 65, and 80 msec. The anatomical abnormalities were least severe in the only patient with a normal H-V interval (50 msec). The prolonged H-V interval was thought to result from stretching of the conduction system over the atrialized right ventricle (ARV). The late depolarization during the splintered R' of the electrocardiogram found during intracardiac mapping of the ARV in three patients confirms the theory that the ARV produces the "second QRS" typically seen in this anomaly. The ARV was particularly irritable, and ventricular fibrillation was produced in two patients during catheter manipulation in this area. In one case the ARV had a shorter refractory period than the body of the right ventricle. Re-entrant supraventricular tachycardia was induced in the only patient with Wolff-Parkinson-White syndrome. In addition to the previously recognized electrophysiologic features reconfirmed here, patients with Ebstein's anomaly of the tricuspid valve usually have: normal position of the bundle of His, prolonged intra- right atrial conduction, prolonged infranodal conduction, and irritable ARV with delayed activation.

Adolescent↗
PubMed1975

Tricuspid and pulmonary valve atresia with aortopulmonary fistula: survival of a patient to 21 years of age.

We report the case of a patient with tricuspid and pulmonic valve atresia, with survival to the age of 21 years. Postmortem examination revealed an anomalous vessel connecting the ascending aorta with the main pulmonary artery. This fistula measured 20 mm by 4 mm, arose independently of the coronary arteries and had the histologic features of an elastic artery. The remarkable longevity was ascribed in part to the maintenance of pulmonary arterial flow by the left-to-right shunt through the anomalous arterial connection.

Adult↗