ISSN:0009-7322    

出版商:OVID    

年代:1975

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

The total incidence of coronary artery spasm during coronary angiography has been reported to be between 0.26% and 0.93%. The rarity of this phenomenon has been invoked to minimize its clinical significance. Review of a one-year experience in our catheterization laboratory showed that coronary spasm occurred in eight of 274 coronary angiograms (2.93%). In three instances, spasm could not be ascribed to catheter tip irritation, and was considered to be spontaneous. Since multiple factors during coronary arteriography might inhibit the occurrence of coronary spasm, it is believed that the incidence of spontaneous spasm may be higher than can be documented during angiography. Coronary spasm may have important clinical significance in various chest pain syndromes and greater methodical attention should be directed toward this phenomenon.

ISSN:0009-7322    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

The reliability of interpretation of coronary arteriography as a diagnostic tool was investigated in a sub study of the VA Cooperative Study of Surgical Treatment for Coronary Arterial Occlusive Disease. Twenty two physicians with varying levels of experience read 13 cine angiograms — blind — on two different oc casions.Analysis of inter- and intraobserver variability showed that angiographic items about which observers were most inconsistent from one reading to the other had the largest interobserver disagreement as well. They were the distal portions of the left anterior descending and left circumflex arteries. Among the items on which there was most consistent agreement — namely, the right main coronary artery and presence of ven tricular aneurysm — there was most often agreement between observers as well. When individual readers were evaluated, some observers were far more consistent in their own readings of all the angiographic items than others. This intraobserver agreement in turn correlated fairly well with how often they agreed with the other observers and with how much experience they reported having in reading coronary cineangiograms.

ISSN:0009-7322    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

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. Reentrant 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 intraright atrial conduction, prolonged infranodal conduction, and irritable ARV with delayed activation.

ISSN:0009-7322    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

Thirty-one left ventricular (LV) biplane angiograms were performed in 28 patients with tricuspid atresia. Measurements of left ventricular end-diastolic volume (LVEDV) and left ventricular end-systolic volume were obtained by the modified Simpson's rule and systolic ejection fraction (EF) calculated. Left ventricular volumes and ejection fractions were also obtained in 19 control patients with no significant heart disease. The patients with tricuspid atresia were classified according to the appearance of the pulmonary vascularity on initial radiologic examination: Group A, decreased pulmonary vascularity; Group B, increased pulmonary vascularity. In the 13 group A infants who were unoperated, LVEDV was increased and EF mildly diminished. In the group B patients LVEDV was increased and EF normal. In the 12 group A patients with surgical shunts LVEDV was elevated. The five group A patients with long-standing systemic artery to pulmonary artery anastomoses (> 10 years) showed the largest LVEDV and the poorest EF. The angiographic data indicate that patients with tricuspid atresia experience significant LV dysfunction as a consequence of longstanding LV volume overload. The early detection of LV dysfunction may be an indication for a right ventricular bypass procedure in these patients.

ISSN:0009-7322    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

The mechanism by which magnesium affects digitalis-induced arrhythmias was studied in dogs with and without beta-receptor blockade. Digoxin was infused at a rate of 2.5&mgr;g/kg/min until ventricular tachycardia developed, then half the animals were given MgSO4, the other half saline. In animals given MgSO4, sinus rhythm was immediately re-established; in animals given saline, ventricular tachycardia persisted. In animals with beta-receptor blockade, MgSO4was as effective in abolishing ventricular tachycardia as in those without beta-receptor blockade.We found no evidence that magnesium re-activated digoxin-inhibited (Na+, K+)-ATPase, altered myocardial or microsomal digoxin binding, or acted via the autonomic nervous system. Magnesium's direct effect on calcium and potassium fluxes across the myocardial cell membrane may be the mechanism of its antiarrhythmic action in digitalis-toxic arrhythmias.

ISSN:0009-7322    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

Abnormalities of left ventricular function and extent of myocardial infarction were studied in relation to prevalence of late ventricular premature contractions (VPCs) in 36 patients in the convalescent stage of acute myocardial infarction (MI). Left ventricular ejection fraction (EF) and percent akinesis (%A) were calculated from gated cardiac blood pool scans; myocardial infarct size was estimated from peak CPK values; and VPCs were detected by 24 hour ambulatory ECGs 2-4 weeks following hospitalization for acute MI. Twenty-two patients had either zero (class 0) or < 30/hour unifocal VPCs (class I). Fourteen patients had > 30/hour unifocal (class II), multifocal (class III) or coupled VPCs (class IV), including ventricular tachycardia. Thirteen of 14 class II-IV patients had EF < 40% compared with only 8 of 22 class 0-I patients. Class II-IV patients had significantly lower mean EF (30.5 ± 2.3 se to 49.6 ± 4.0)P< 0.01, higher mean %A (28.1 ± 2.2 to 16.9 ± 3.7)P< 0.05, and higher mean peak CPK (1350 ± 187 to 721 ± 155)P< 0.05 than class 0-I patients. These data suggest that VPCs may not be an independent risk factor for sudden cardiac death in the convalescent phase of MI.

ISSN:0009-7322    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

Time dependent changes in the electrophysiological properties of the atrioventricular conducting system (AVCS) were determined at two or more cycle lengths (CL) in 22 patients using bundle of His (H) electrograms, incremental atrial pacing and atrial extrastimulus method. The atrioventricular (A-H interval) and intraventricular (H-V interval) conduction times and refractory periods (RP) of the atrium, the A-V node (AVN) and His-Purkinje system (HPS) were measured during the control period, and repeat measurements were made after a 30 minute interval in eight patients (group A), after a 60 minute interval in nine (group B) and after 30 and 60 minute intervals in five (group C). No statistically significant changes from control values were seen after 30 and 60 minute intervals in any group in sinus rate, A-V nodal conduction time and the onset of A-V nodal Wenckebach block. H-V intervals were identical to the control values in all groups. Insignificant changes from control values occurred in RP of the atrium and HPS. Only the functional refractory period (FRP) of the AVN showed a statistically significant decrease from control values in groups B and C. This decrease could be explained by changes in autonomic tone. These observations in general confirm the reproducibility of electrophysiological properties of AVCS within one hour, and further support the validity of the techniques utilized in this and previously reported studies in the evaluation of cardioactive drugs.

ISSN:0009-7322    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

Long rhythm strips were analyzed from five patients with frequent ventricular extrasystoles. The predominant pattern was quadrigeminal; i.e., three sinus beats between extrasystoles. However, about 20% of the interectopic intervals contained numbers of sinus beats (S) greater than three. Analysis of the distribution of such values of S > 3 revealed that there were many more odd than even values (P< 0.001). Also, carotid sinus pressure yielded only odd values of S > 3. This predominance of odd values strongly suggested the existence of concealed extrasystoles. Therefore, all odd values of S > 3 were analyzed to determine whether they satisfied the criterion for concealed bigeminy (S = 2n − 1) or for concealed quadrigeminy (S = 4n − 1). The distribution was found to satisfy the criterion for concealed bigeminy, suggesting that the quadrigeminal pattern was a manifestation of a 2:1 rather than a 4:1 block in a re-entry loop. Stable quadrigeminy occurs often in concealed bigeminy, because the re-entrant impulse finds the myocardium ex citable after a normal R-R interval but refractory after a compensatory pause.

ISSN:0009-7322    

出版商:OVID    

年代:1975

数据来源: OVID