ISSN:0009-7322    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

Conventional exercise electrocardiographic criteria usually involve patterns with a horizontal or downsloping ST segment. In the present study we present criteria based on upsloping ST segments and compared these criteria with the conventional criteria. Using upsloping ST-segment criteria, the amount of STsegment depression at 80 msec after the end of the QRS complex is used as a parameter (ST criterion E, with a depression of 100 mV, and ST criterion F, with a depression of 200 mV). In the graded exercise test a bicycle ergometer was used. The ECG leads were CM5 and CC. The results of exercise electrocardiography were compared with the findings from coronary arteriography.In 623 selected patients (565 males and 58 females), application of conventional ST criteria gave a sensitivity of 56% and a specificity of 94%; with application of the ST criteria E or F, sensitivity was 75% and specificity 90%. In the 58 females use of these new criteria resulted in a sensitivity of 76% and specificity of 88%. Ninety-three patients (15%) could be classified as positive exercise responders by the sole presence of an upsloping ST segment (type E or F). Sixty-eight percent of the patients with type E and 75% with type F had two- or three-vessel disease (coronary obstructions 2 50%). We conclude that ST criteria based on upsloping ST segments significantly increase the diagnostic yield of the exercise ECG.

ISSN:0009-7322    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

The influence of acute myocardial ischemia and changes in ventricular dimensions on endocardial and epicardial electrograms were evaluated in 17 anesthetized open-chest dogs before and after left ventricular volume expansion and before and after coronary artery ligation. In eight dogs, regional myocardial blood flow was determined by the labeled microsphere technique. Endocardial QRS (endo-QRS) amplitude in ischemic and nonischemic zones, and epicardial QRS (epi-QRS) in nonischemic zones maintained a negative linear relation with left ventricular end-diastolic dimension before and after coronary artery ligation, although acute ischemia decreased endo-QRS independently. Epi-QRS amplitude in the ischemic zone decreased after coronary artery ligation but changed inconsistently during volume expansion. Ischemia-induced epicardial STsegment elevation decreased during volume expansion and was associated with improved epicardial blood flow. Changes in epi-QRS in ischemic zones, however, were not related to epicardial blood flow during volume expansion. These findings indicate the potential problems of using changes in QRS amplitude for determining the extent of myocardial ischemic injury.

ISSN:0009-7322    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

Variations in the frequency of complex ventricular arrhythmias were evaluated by consecutive 24-hour long-term electrocardiographic recordings over 4 days using a two-channel recorder and computerassisted analysis system with a weighted relative mean error of 7.5 i 5% (SD). Twenty patients (mean age 58 ± 9 years [SD]) with various cardiac disorders were selected if they had a daily average of more than 30 ventricular ectopic complexes per hour. Twenty patients had ventricular couplets and 14 patients had ventricular tachycardia (at least triplets). The mean daily number of either couplets or ventricular tachycardia was subjected to a four-factor nested analysis of variance to determine the sources of variation in ectopic frequency. Differences in hourly rates accounted for 30% of the variation in the frequency of ectopic complexes. Statistical methods were applied to determine the change in frequency of complex arrhythmias necessary to exceed that attributable to spontaneous variation alone at the p < 0.05 level. Using a typical protocol, for example, comparing a 24-hour test period with a 24-hour control period would require a 65% decrease in mean hourly frequency of ventricular tachycardia and 75% reduction in the frequency of couplets to demonstrate therapeutic efficacy rather than a reduction due to spontaneous variation alone.

ISSN:0009-7322    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

To elucidate the abnormalities in ventricular activation sequence in human left bundle branch block (LBBB), epicardial mapping was performed in five patients, ages 52–58 years, undergoing coronary bypass surgery, and the results were compared with similar data published from patients without conduction defect. Three patients had chronic and two patients intraoperative LBBB. ECGs during LBBB revealed a QRS duration of 130–160 msec and a mean QRS axis of −15° to +45. Epicardial mapping revealed 1) anterior right ventricular (RV) epicardial breakthrough (5–26 msec after QRS onset), normal in site in all patients, but abnormally early in timing relative to QRS onset in three patients with chronic LBBB, and earlier compared with preoperative maps in two patients with intraoperative LBBB; 2) normal location of latest RV epicardial activation in four of five patients, but abnormally late occurrence of this event 100, 108 and 110 msec after QRS onset in three of five patients; 3) absence of discrete left ventricular (LV) epicardial breakthroughs in all patients; 4) slow transseptal epicardial activation (crowded isochrones) from right to left, with anteroseptal crossing preceding inferoseptal crossing; 5) activation of the anterolateral left ventricle before the inferior LV epicardium; 6) more widely spaced isochrones, implying more rapid conduction, over the LV free wall epicardium; and 7) location and timing of latest LV epicardial activation in an abnormal site, and abnormally late relative to QRS onset (113–140 msec, mean 124 msec) in all patients. This event occurred a mean of 20 msec before the end of the QRS in the five patients.In conclusion, with normal axis, human LBBB is associated with initiation of ventricular activation closer to anterior RV recording sites than is normal activation, slow leftward transseptal activation, a generally anteroinferior orientation of LV activation, and probable engagement of the distal LV Purkinje system during the latter part of the QRS.

ISSN:0009-7322    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

In the present study, we investigated the technique and reliability of measuring digital blood pressure by means of a rigid, airtight container (a bladder-free cuff) and a photocell placed on the digit. As cuff pressure increased, the position of digits in the cuff was maintained in the hand by fixing one or two fingers inside the cuff and, in the foot, by using a supporting stick to keep the distance from the cuff to the bed constant. An airtight seal inside the cuff was achieved using a thin rubber sleeve and adhesive tape. Blood pressures letermined by the bladder-free cuff correlated well with those obtained by the conventional cuff with bladder.By using the bladder-free cuff, blood pressure could be measured at the distal phalanx of the fingers and in all toes.

ISSN:0009-7322    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

The offspring of parents belonging to the original Framingham Heart Study cohort, and spouses of these offspring, were examined beginning in 1971. Cardiovascular examinations similar to those performed on the parents in 1952–1953 were given to offspring and their spouses. The mean blood pressure (BP) appeared to be lower in the female offspring-spouses than in the cohort mothers. Comparable multivariate analyses on 3588 offspring and spouses of both sexes, ages 20–49 years, and 1842 parents, ages 30–49 years, confirmed the frequently reported importance of weight, heart rate, alcohol consumption, glucose and hematocrit or hemoglobin as independent positive correlates and smoking as an inverse correlate of both systolic and diastolic BP. In the offspring-spouse population, the additional measured variables of total serum proteins and plasma triglycerides added significantly to prediction of BP in both sex groups, and a less striking negative association was found for serum phosphorus. The findings for serum proteins and triglycerides were supported in a separate population of middle-aged twin men. Even with the additional measured variables, only 28–34% of the total BP variance is explained in these populations.

ISSN:0009-7322    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

Changes in cardiorespiratory symptoms and coronary disease risk indicators over an average 11/2-year period were assessed in 9392 persistent cigarette smokers and 3825 persons who quit smoking between two multiphasic checkups. The prevalence of questionnaire-reported chronic cough fell markedly in subjects who quit a one-or-more-pack/day habit (e.g., from 11.2% to 1.8% in white men,p < 0.001). However, chest pain, shortness of breath and exertional leg pain showed no consistent improvement in quitters compared with persistent smokers. Weight gain was about 2–3 lbs greater in quitters, but changes in blood pressure were small and not consistent across race-sex groups, nor were there consistent differences between persistent smokers and quitters in trends in vital capacity, cholesterol or prevalence of ECG abnormality. Quitting was associated with increase in serum uric acid levels of about 0.2–0.5 mg/dl and relative falls in hemoglobin, leukocyte count and serum glucose levels, all consistent with smoker-nonsmoker differences previously found in cross-sectional studies. Except for the small increases in weight and uric acid levels, quitting smoking did not appear to increase risk of coronary heart disease by other mechanisms.

ISSN:0009-7322    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

The predictive value of a diagnostic test estimates the likelihood for presence or absence of disease in a patient with a positive or negative test result (PV, O, or PVYR.,). We evaluated the predictive values of serum activities of the heart-specific creatine kinase isoenzyme MB (CK-MB), aspartate aminotransferase, lactate dehydrogenase, CK, and ECG in 401 consecutively admitted patients suspected of acute myocardial infarction (AMI). The study showed that CK-MB (PVPOI = 0.98, PV.g, = 1.00) was better than the other enzymes (single as well as serial) and ECG, evaluated both separately and in combinations. In all cases of AMI CK-MB was positive within 17 hours from admission. Replacement of the standard enzymes with CK-MB provides a faster and safer diagnosis of AMI and reduces hospitalization time considerably for patients without AMI.

ISSN:0009-7322    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

The usefulness of thallium-201 (Tl-201) exercise myocardial scintigraphy in identifying patients with multivessel coronary artery disease (MVCAD) and residual jeopardized myocardium after myocardial infarction (MI) was evaluated in 32 patients 3 weeks after MI. All patients underwent 1) limited multilead submaximal treadmill testing, 2) thallium-201 (TI) myocardial scintigraphy at end-exercise and at rest, and 3) coronary and left ventricular angiography.TI-201 perfusion defects were categorized as either reversible (ischemia) or irreversible (scar). The conventional exercise test was designated positive if there was ST depression 2 1 mm and/or angina. Jeopardized myocardium (JEP) was defined angiographically as a segment of myocardium with normal or hypokinetic wall motion supplied by a significantly stenotic major coronary artery. MVCAD was defined as two or more significantly stenotic coronary arteries. “Significant” coronary stenosis was categorized as either 50–69% diameter narrowing or 2 70% diameter narrowing, thereby yielding, respectively, two subgroups each of jeopardized myocardium (JEP-50 and JEP-70) and MVCAD (MV-S0 and MV-70).Clinical findings of angina, heart failure or ventricular arrhythmias during the late convalescent period after MI occurred in four of 10 patients (40%) with MV-50, five of 16 (31%) with MV-70, four of 10 (40%) with JEP-50 and five of 18 (28%) with JEP-70, and thus were insensitive for detecting MVCAD and JEP.Reversible ischemia and/or a positive conventional exercise test occurred in five of 10 patients (50%) with MV-50, 13 of 16 (81%) with MV-70, four of 10 (40%) with JEP-S0 and 15 of 18 (83%) with JEP-70. All eight patients with both TI-201 reversible ischemia and a positive conventional exercise test had JEP-70. In 30 of 31 patients (97%) with angiographic asynergy, TI-201 scar was detected. No complications were associated with exercise testing.Thus, 3 weeks after MI, Tl-201 exercise myocardial scintigraphy is a safe, useful, noninvasive tool for identifying patients with MVCAD and residual JEP and is much more reliable than clinical findings during convalescence after MI.

ISSN:0009-7322    

出版商:OVID    

年代:1980

数据来源: OVID