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Biomedical subjects

O Hess

Publications and source records attributed to O Hess.

At least 37 records · Page 2Linked to original sources

Spontaneous course of aortic valve disease.

The fate of patients with aortic valve disease of varying degrees of severity and the relationship between symptoms and haemodynamic status have been studied in 190 adults undergoing cardiac catheterization during the last two decades. During the follow-up period, 41 patients died and 86 underwent aortic valve replacement; these two events were the endpoints for the calculation of 'event-free' cumulative survival. First-year survival in haemodynamically severe disease was 60% in aortic stenosis and 96% in aortic regurgitation; in moderate and mild disease (in the absence of coronary artery disease) first-year survival was 100% in both groups. After 10 years, 9% of those with haemodynamically severe aortic stenosis and 17% of those with severe regurgitation were event-free, in contrast to 35% and 22%, respectively, of those with moderate changes and 85% and 75%, respectively, of those with mild abnormalities. In the presence of haemodynamically severe disease, 66% of the patients with stenosis and 14% of those with regurgitation were severely symptomatic (history of heart failure, syncope or New York Heart Association class III and IV); 23% of patients with moderate stenosis and 14% with moderate regurgitation were also severely symptomatic. Only 40% of those with disease that was severe both haemodynamically and symptomatically with either stenosis or regurgitation survived the first two years; only 12% in the stenosis group and none in the regurgitation group were event-free at 5 years. Patients with haemodynamically severe aortic stenosis who had few or no symptoms had a 100% survival at 2 years; the comparable figure for the aortic regurgitation group was 94%; 75% of the patients in the stenosis group and 65% in the regurgitation group were event-free at 5 years. In the moderate or mild stenosis and regurgitation groups there was no mortality within the first 2 years in the absence of coronary artery disease, regardless of symptomatic status. Haemodynamically and symptomatically severe aortic stenosis and regurgitation have a very poor prognosis and require immediate valve surgery. Asymptomatic and mildly symptomatic patients with haemodynamically severe aortic stenosis are at low risk and surgical treatment can be postponed until marked symptoms appear without a significant risk of sudden death. In severe aortic regurgitation, the decision for surgery should depend not only on symptoms but should be considered in patients with few or no symptoms because of risk of sudden death. In the absence of coronary artery disease, moderate aortic valve disease does not require valve operation for prognostic reasons.

Adolescent↗

[A new thermodilution catheter for the determination of heart-minute volume in the arterial system].

A double-lumen polyethylene pigtail catheter (F8, length 100 cm) for the determination of cardiac output (CO) in the arterial system is described. Following femoral insertion of the catheter, 10 ml of ice-cold saline is injected into the left ventricle through the distally ending lumen (0.8 mm2). Through the second lumen (0.8 mm2) which opens 50 cm behind the catheter tip, a thermistor probe (F3, teflon) is advanced into the descending aorta for recording of thermodilution curves. In 21 patients CO was determined first by the Fick method and then by thermodilution in the arterial system. CO by thermodilution correlated favorably with CO by Fick (r = 0.92, SEE 518 ml = 11% of the mean value). There was no systematic deviation from the reference CO. A similarly good correlation existed between stroke volume (SV) by thermodilution and SV by Fick (r = 0.86 SEE 11 ml = 15% of the mean value). Heart rate during thermodilution was 71 bpm, during Fick output estimation 72 bpm (not significant). Following withdrawal of the thermistor probe, simultaneous measurements of left ventricular and aortic pressures can be performed.

Cardiac Catheterization↗

[Spurious aneurysm after myocardial infarct].

False aneurysms of the left ventricle after myocardial infarction arae the result of perforation, which usually require early surgical treatment. The clinical features are not characteristic. The chest x-ray may provide important evidence for the diagnosis. Non-invasive diagnosis is possible by means of echocardiography and computer tomography; it is confirmed by angiocardiography. The authors experience with nine cases is described.

Adult↗

[Myocardial damage in coronary air embolism (author's transl)].

Haemodynamic changes after intracoronary air embolism (0,02 ml/kg air in the left coronary artery) were studied in 16 dogs. The air was introduced in 8 animals during cardiopulmonary bypass and in 8 animals without bypass. In both groups the air embolization caused acute ischemia with myocardial necrosis. Immediately after the injection the anterior wall became akinetic; 24 hours after injection CPK increased to more than 800 U. One half of the animals without cardiopulmonary bypass died during acute ischemia due to refractory arrhythmias; there was no mortality in the group with cardiopulmonary bypass. The left ventricular damage due to air embolization cannot be significantly reduced with cardiopulmonary bypass; the bypass only helps to "tide over" the animal during the period of acute ischemia.

Animals↗

[Surgical treatment of myocardial aneurysms. Indications and results].

The long term results of 95 left ventricular aneurysmectomies are presented. In 47 patients simultaneous aorto-coronary bypass surgery was performed. 53 patients presented preoperatively with congestive heart failure; 8 out of these died within the first postoperative month, while 5-year survival rate (actuarial method) was 52%. Two thirds of this patient group improved. None of the 42 patients without preoperative congestive heart failure died early. 5-year survival rate was 93% and subjective improvement was recorded in one half of this subgroup. Comparison of pre- and postoperative angiograms (40 patients) revealed an increase in left ventricular ejection fraction reflecting the removal of the non-contracting segment. The ejection fraction of the contracting segment of the left ventricle improved after aneurysmectomy, especially in patients with preoperative congestive heart failure. In conclusion, aneurysmectomy improves left ventricular function and the symptoms of heart failure; moreover, it prevents perforation of false aneurysms. Its effect on arrhythmias could not be determined conclusively. Angina may be improved by simultaneous aorto-coronary bypass surgery.

Angina Pectoris↗

[Echocardiography in the evaluation of ventricular function].

The ultrasonic beam used for quantitative assessment of left ventricular (LV) function traverses the heart in a projection similar to the familiar angiographic left anterior oblique projection. It crosses the anterior wall of the right ventricle, the right ventricular cavity, the interventricular septum, the LV cavity and the posterior wall of the left ventricle. Whereas the cyclic changes of the right ventricular diameter are rarely clearly determined by echocardiography, the easily assessed cyclic changes of the LV endocardial transverse diameter are useful measure of LV FUNCTION. Of practical importance are the percentage of systolic shortening of the LV diameter (%Sh) and the mean velocity of circumferential fiber shortening (VCF). There are several factors, such as placing of the ultrasonic transducer, the shape and size of the LV cavity and rotational movements of the heart as a whole, that influence echocardiographic determination of the transverse LV diameter. In patients with asynergic contraction, %Sh and VCF cannot be used as measures of overall LV performance, but localized contraction disturbances of the septum and the posterior wall may be detected from the reduced extent of wall motion in a given LV segment during a full sweep from the base to the apex. The most important indications for echocardiographic assessment of LV function are valvar diseases with chronic LV pressure or volume overload, and congestive cardiomyopathy. Echocardiography has proved useful in serial evaluation of LV function in patients undergoing valvar heart surgery. Assessment of LV volume by standard echocardiography using the cubic formula is not satisfactory. More accurate determination of volumes is provided by formulas that include the actual ratio of the LV long axis to the minor axis.

Aortic Valve↗

[Bi-ventricular endo-myocardial fibrosis (author's transl)].

Bi-ventricular endo-mycardial fibrosis was diagnosed in two European women. Clinically there was severe cardiac insufficiency in the presence of only moderate radiological cardiac enlargement. Haemodynamically there was restricted filling, but otherwise normal systolic ventricular function. The diagnosis depended on the angio-cardiographic demonstration of a small, globular left ventricular chamber with a tubular narrowed right ventricle with a thickened wall, particularly at the apex. In one patient the endo-myocardial fibrosis was also demonstrated by echocardiography.

Adult↗