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Biomedical subjects

I Hoffman

Publications and source records attributed to I Hoffman.

At least 55 records · Page 3Linked to original sources
PubMed1978

Significance of new Q waves after bypass grafting: correlations between graft patency, ventriculogram, and surgical venting technique.

New postoperative electrocardiographic Q waves have been described in eight of 40 per cent of patients undergoing bypass grafting for coronary artery disease. Various theories have been proposed to explain these new Q waves. Correlations of new Q waves to vein bypass occlusion, prolonged pump time or aortic cross-clamping time are controversial. Indeed, whether or not the appearance of new postoperative Q waves means real transmural myocardial infarction is not clear. We report herein our experience with postoperative Q waves in 56 patients with vein bypass grafts and the relationship of new Q waves to ventricular venting, graft patency, and the postoperative ventriculogram. Our observations indicate that: (1) Not all Q waves are due to occlusion of the saphenous bypass grafts (as noted by others). (2) A certain percentage of new Q waves may not reflect true transmural myocardial infarction, especially when all the vein grafts are patent and the postoperative ventriculograms show improvement. (3) Some new Q waves reflect true transmural infarction due to occlusion of grafts or of distal coronary arteries with deteriorated left ventriculograms. (4) The high incidence of new Q waves in patients with ventricular vents is probably due to direct myocardial trauma at the apex of the left ventricle.

Adult↗
PubMed1978

Results of aortocoronary bypass grafting in patients with subendocardial infarction: late follow-up.

Twenty-eight patients with subendocardial infarction (Group A) were compared with 28 patients with unstable angina (Group B) and 28 with stable angina (Group C) matched for age and sex. The three groups did not differ in prevalence of diabetes, hypertension, old infarction or duration of disease. There were no significant differences in number of diseased vessels, coronary score, abnormal left ventricular wall motion or left ventricular end-diastolic pressure. Angiograms performed 2 weeks postoperatively revealed closure of 3 of 31 grafts (16 patients) in Group A, closure of 3 of 34 grafts (17 patients) in Group B and closure of 6 of 50 grafts (22 patients) in Group C (differences not significant). Postoperative angiograms showed improved wall motion in 37 percent of Group A, 53 percent of Group B and 36 percent of Group C (differences not significant). Postoperative new Q waves appeared in one hospital in Group A and in two patients in Groups B and C. There were no hospital or late deaths. In a mean follow-up period of 29 months, 68 percent of patients in Group A, 61 percent in Group B and 54 percent in Group C were asymptomatic. Thus, bypass grafting was performed with similarly low mortality and morbidity in patients with subendocardial infarction and in those with angina; more than one third of postoperative angiograms in the three groups showed improved wall motion; and late follow-up studies demonstrated functional improvement in the majority of patients in all three groups.

Angina Pectoris↗
PubMed1978

A note on simultaneous and interleaved masking.

Speech and noise were switched periodically from ear to ear at a rate high enough to create a binaurally fused image. Two masking conditions were investigated. In one the speech and noise were switched in unison from ear to ear such that both speech and noise were presented simultaneoully to the same ear. In the other case, the speech and noise were interleaved such that there was no simultaneous overlap of the speech and noise at any one ear. The difference in masking levels between these two conditions was found to be on the order of 20 dB. The technique offers some interesting possibilities for investigating the relative effects of central and peripheral masking in both normal and hearing-impaired listeners.

Acoustic Stimulation↗
PubMed1976

Vectorcardiographic, electrocardiographic, and angiographic correlations in apparently isolated inferior wall myocardial infarction.

Twenty-six patients with ECG evidence of localized inferior myocardial infarction and poor ejection fraction (less than 50 per cent) were compared with 26 patients with similar ECG's, but with normal ejection fraction (over 50 per cent). The poor ejection fraction group had significantly more frequent and more severe disease in left anterior descending artery and a higher incidence of triple coronary obstruction than the normal ejection fraction group. The poor ejection fraction group had a significantly greater incidence of ventricular asynergy in the anterior and apical segments of left ventricle. Vectorcardiography was available in 35 of the 52 patients studied and frequently supplied diagnostic information not available in the scalar ECG's. Of 18 patients with scalar ECG patterns of isols, vectorcardiography identified five cases with anterior infarction, three with left ventricular hypertrophy, and one with left anterior hemiblock. Vectorcardiography is a valuable supplementary tool in the clinical assessment of patients with apparently isolated inferior infarction. When extensive coronary and poor ventricular function exist, VCG clues may be expected in about half the patients.

Angiocardiography↗
PubMed1976

Anterior conduction delay: a possible cause for prominent anterior QRS forces.

Prominently anterior QRS forces often present a diagnostic dilemma. Frequently, right ventricular forces may be eliminated on clinical grounds and dorsal infarction is therefore suspected, especially in a clinical setting of coronary artery disease. In five such patients studied angiographically, the coronary disease was concentrated in the left anterior descending artery and the ventricular dysfunction confined to the anterior wall of the left ventricle. In a sixth case, the prominent anterior forces were observed intermittently together with left anterior hemiblock. These observations, in addition to serial studies following surgery, strongly suggest that the mechanism for prominent anterior QRS forces in these cases is conduction delay in an anterior division of the left bundle branch system.

Adult↗
PubMed1976

New Q waves after bypass grafting: correlations between graft patency, ventriculogram and surgical venting technique.

New Q waves were observed in 35 (11%) of 321 patients undergoing saphenous vein bypass grafting with an overall mortality rate of 1.1%. Twenty-eight (80%) had postoperative arteriograms and ventriculograms and are reported. Ventricular venting was used intra-operatively in 17 patients and atrial venting in 11. The incidence of new Q wave was 22% in patients with ventricular venting and 5.5% in those with atrial venting (p less than 0.05). Complete or incomplete revascularization did not affect the incidence of new Q waves. New Q waves appeared in a zone of myocardium supplied by a grafted artery in all except two patients with ventricular venting in whom Q waves occurred within the zone of myocardium supplied by diseased ungrafted vessels. In the ventricular venting group, seven (41%) demonstrated an improved or unchanged postoperative ventriculogram and ten (59%) had deteriorated ventriculograms. In 11 patients with atrial venting, nine (82%) showed improved or unchanged postoperative ventriculograms and two (18%) had deteriorated ventriculograms. Ventricular venting patients with improved or unchanged postoperative ventriculograms had 7% graft closure as compared to 5% of those with atrial venting (pNS). Graft closure rate was 44% in ventricular venting and 20% (pNS) of patients with atrial venting who had deteriorated left ventriculograms. These findings indicate poor correlation between new Q waves and graft closure. Improved postoperative ventriculograms corrleated well with graft patency despite new Q waves. The etiology of new post bypass graft Q waves are varied. They include ventricular trauma and conduction delays resulting from surgery or venting, as well as infarction. This may be due to compromised arterial inflow either in nonoperated vessels or in the vessels distal to the anastomosis with patent grafts, or due to occluded grafts.

Coronary Artery Bypass↗
PubMed1976

Medical-surgical aspects of left main coronary artery disease.

Disease of the left main coronary artery compromises circulation to the major part of the left ventricle and thus threatens massive myocardial infarction and sudden death. Cardiac catheterization and coronary bypass surgery, in previous reports, have been associated with high mortality and morbidity rates. We report 50 patients with over 50 per cent narrowing of the left main coronary artery. The clinical pattern in these patients was variable and a left main coronary artery lesion could not be predicted before coronary angiography. There was only one death during cardiac catheterization. One patient died while waiting for elective surgery. Coronary bypass surgery was performed in 42 patients; one died during surgery. Forty-one patients are alive at 2 to 39 months follow-up (mean, 19 months). Thirty-six patients are asymptomatic or have minimal symptoms. Compared to the prognosis in patients with left main coronary artery stenosis treated medically, coronary bypass surgery performed on urgent basis offers a much better prognosis. Both coronary angiography and bypass surgery can be performed in these patients with a very low risk.

Adult↗
PubMed1975

Preoperative coronary angiographic prediction of bypass flow and short-term patency.

A quantitative preoperative coronary angiographic index was defined in 148 patients undergoing coronary revascularization. Each diseased vessel was scored 0-3, for both diameter and quality of run-off. The sum of the scores for diameter and run-off constituted the numerical index for the diseased vessel. Correlations between the index and graft flow measured by electromagnetic flow meter at surgery were established in 259 bypassed vessels. The highest scores (5-6) were associated with higher flows, and the lower scores (0-4) with the lower flows (P less than 0.005). Repeat angiography performed 2 wk postoperatively in 110 patients demonstrated 174 graft patencies and 15 graft closures. Mean flow in open grafts was 82 +/- 41 ml/mn vs. 60 +/- 23ml/mn in closed grafts (P less than 0.005). It is concluded that graft flow is predictable from preoperative Coronary Angiographic Index and that higher flow and index scores are more likely to be associated with graft patency than low flows and index scores.

Angina Pectoris↗
PubMed1975

Relation of left ventricular contractile patterns in coronary artery disease to the electrocardiogram and vectorcardiogram.

Two hundred thirty patients with coronary artery disease (CAD) were studied with left ventriculography, coronary arteriography, electrocardiography (ECG) and vectorcardiography (VCG) to determine how well left ventricular (LV) contractile defects could be predicted from the ECG-VCG patterns and how this was related to the coronary disease location and severity. Of 124 patients with infarction patterns on ECG-VCG about 50% had LV contractile defects localized to the corresponding ECG-VCG abnormalities, i.e., antero-apical asynergy with anterior infarction patterns, inferior asynergy with inferior infarction patterns, or antero-apical plus inferior asynergy with anterior plus inferior patterns. About 20% in each infarction group had unexpected synergy on ventriculography except for patients with dorsal infarction patterns (synergy in 68%) who are discussed as a special problem. Another 25-30% of patients had more extensive contractile abnormality than indicated by the ECG-VCG patterns. In 106 patients with left ventricular hypertrophy, normal QRS-abnormal T and normal QRS-T on ECG-VCG, 65-70% had synergy. However, 30-35% had asynergy in various combinations not suspected from the ECG or VCG. Coronary artery disease severity was less pronounced in patients with synergy than with asynergy and single vessel disease was more common in the former, 47% versus 18-30% in the latter. However, coronary artery disease severity was the same for all ECG-VCG groups except for anterior plus inferior infarction patterns where it was most severe.

Coronary Disease↗
PubMed1975

Failure of the omnicardiogram to predict coronary artery disease in patients with normal resting electrocardiograms.

Seventy-two male patients over the age of 35 had normal resting twelve lead eletrocardiograms (ECG's). All patients were studied by invasive techniques including complete right and left sided cardiac catheterization, selective coronary arteriography, and left ventricular angiography. All patients had been referred because of chest pain with a presumed diagnosis of coronary artery obstruction and myocardial ischemia. Omnicardiograms were generated from the twelve lead ECG's and diagnosed as "abnormal" or "normal" by observers having no knowledge of the cardiac catheterization findings. Of 72 patients studied, 21 were free of coronary artery disease. Of these, 14 (66%) had "abnormal" omnicardiographic reports. Seven (33%) had "normal" omnicardiograms, indicating an incidence of false positive "abnormal" omnicardiographic reports as 66%. Fifty-one patients had hemodynamically significant coronary artery disease. In this group, 19 (38%) were reported as "normal" by omnicardiogram, an incidence of false negative diagnosis of 38%. When the patients with coronary artery disease were classified as to single, double, or triple coronary obstruction, it was evident that the omnicardiogram had failed to separate patients with more extensive disease. Of the 32 patients with "abnormal" omnicardiograms, 56% had double or triple vessel disease, while of the 19 patients with "normal" omnicardiograph reports, 78% had double or triple vessel disease. Similarly, the omnicardiograms failed to identify the patients with abnormal left ventricular angiography. Of 19 patients with coronary artery disease and "normal" omnicardiograms, only 8 (42%) had normal ventricular angiography. However, of the 32 patients with coronary disease and "abnormal" omnicardiograms, only 11 (34%) had abnormal ventriculogram. The omnicardiogram cannot be considered a useful technique for predicting the presence or severity of coronary artery disease or for the identification of abnormal left ventricular function in patients with known coronary artery disease.

Adult↗