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Biomedical subjects

H Hirzel

Publications and source records attributed to H Hirzel.

At least 19 recordsLinked to original sources
PubMed1993

The internal mammary artery 'string phenomenon'. Analysis of 10 cases.

The internal mammary artery (IMA) string sign has been described as a narrowing of IMA grafts in the late course after coronary artery bypass grafting. It has been assumed that this phenomenon was due to competitive flow in grafts connected to only mildly stenosed coronary arteries. We analyzed 10 cases of IMA string sign operated on between March 1988 and June 1991. Bilateral IMA was used in six cases and unilateral IMA in four. The mean interval between operation and reangiography was 14 +/- 11 months. String sign of the whole length of the IMA was detected in nine cases, and of the distal part between two sequential anastomoses in one. In all cases, the stenosis of the vessel bypassed with the narrowed graft proved to be only mild (50% or less) at reangiography. In all six cases with bilateral IMA grafts, the contralateral IMA was widely patent. These were all connected to highly stenosed or occluded coronary arteries. With respect to this observation, there is a high index of suspicion that the string phenomenon occurs due to competitive flow in only mildly stenosed coronary arteries. We decided, for our strategy in coronary artery surgery, still to aim at complete revascularization using IMAs as much as possible, but to avoid connecting IMA grafts to only mildly or moderately stenosed coronary arteries.

Coronary Angiography↗
PubMed1991

[Developments in mitral valve surgery].

Between 1987 and 1990 we operated on 104 patients for mitral valve disease. If possible the valve was reconstructed according to CARPENTIER's technique: 8 of 28 stenotic, 43 of 57 regurgitant and 2 of 7 mixed lesions were repaired. Twelve patients underwent re-replacement of a previously inserted mitral prosthesis. Six patients died early (7.8% after replacement, 8% after isolated replacement, 3.7% after repair and 2% after isolated repair). Five of these six patients were in NYHA class IV preoperatively. Seven patients died late after a mean observation period of 18 months (5 after replacement, 1 after double valve replacement and 1 after repair and multiple coronary bypass surgery). Prognosis is best for patients whose valve can be repaired and who are not already in NYHA class IV. The postoperative NYHA class for surviving patients is excellent (1.3 in the replacement group and 1.2 after repair).

Adult↗
PubMed1987

The use of invasive techniques, angiography and indicator dilution, for quantification of valvular regurgitations.

Angiographic techniques have been used for the quantification of mitral or aortic and rarely tricuspid regurgitation. Mitral or aortic regurgitant volume per beat and the regurgitation fraction (fao and fm, respectively) are obtained from the angiographic determination of total left ventricular stroke volume (TSV) and forward stroke volume (FSV) estimated by a different technique. Although this procedure is generally accepted as the gold standard for quantification of left heart regurgitations, there are several limitations: In the presence of mitral and aortic regurgitation no separate quantification of fao and fm is feasible; heart rate at the time of determination of FSV (from Fick or dye dilution cardiac output) and of TSV (angio) may be different; there is a tendency to consistently overestimate stroke volume by angio techniques; repeated estimations of TSV by angio are influenced by the circulatory effects of the contrast dye. In contrast indicator dilution techniques, where upstream and downstream sampling allow the simultaneous estimation of forward and regurgitant flow, the accuracy of the determination of FSV is well established and repeated estimations of fao and fm are possible because the indicators do not have cardiovascular effects. These methods are, however, crucially dependent on thorough mixing of the regurgitant volume with the blood in the upstream chamber. In 23 patients with isolated aortic regurgitation there was a positive correlation between fao evaluated by thermodilution and fao determined by the biplane angio-Fick method (r = 0.59). fao by thermodilution averaged 0.40 and fao by angio-Fick 0.46 (NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Angiocardiography↗
PubMed1984

[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↗
PubMed1982

[Ventricular septal defect after operation in hypertrophic obstructive cardiomyopathy (author's transl)].

After surgical resection in idiopathic hypertrophic subaortic stenosis, a ventricular septal defect was observed in one patient at a later date. The defects was closed in a second operation. - The hemodynamically relevant changes in the vascular bed of the lung with preoperative congestion and postoperative shunt found their expression in discrete changes only of the chest x-ray.

Cardiomyopathy, Hypertrophic↗
PubMed1981

[How dependable is the end systolic pressure/volume relationship for the determination of left ventricular contractility in aortic valve diseases?].

The validity of the end-systolic pressure/volume ratio (ESP/ESVI) was evaluated in 88 patients with aortic valve disease (31 with aortic stenosis, 28 with aortic insufficiency and 29 with combined valve disease) by comparing the ESP/ESVI ratio with left ventricular systolic function parameters. The results demonstrate that in practice a normal EST/ESVI ratio excludes depression of myocardial contractility. A reduced ESP/ESVI ratio found in 57 patients did, however, correspond to other systolic function parameters indicating depressed or possibly depressed contractility in only 38 patients (66%), whereas biplane left ventricular ejection fraction and the isovolumic velocity indices were normal in 19 patients (33%) - 10 of whom had aortic insufficiency, 8 combined valve disease and only 1 aortic stenosis. It is therefore concluded that the ESP/ESVI ratio is of possible value for the diagnosis of depressed contractility only in patients with aortic stenosis.

Adult↗
PubMed1978

[Percutaneous transluminal dilatation of chronic coronary stenoses. First experiences].

The technique of percutaneous transluminal dilatation of coronary artery stenosis consists of a catheter system introduced via the femoral artery under local anesthesia. A preshaped guiding catheter is positioned in the orifice of the coronary artery and through this a dilatation catheter is inserted into the branches if the artery. This dilatation catheter (outer diameter 0.5--1.25 mm) is equipped with a sausage-shaped distensible segment (balloon) at the tip. The balloon is inflated to a pressure of 5 atm. This pressure compresses the atherosclerotic material in a direction perpendicular to the wall of the vessel, therby dilating the lumen. Up to now 29 patients have been treated with primary success in 23 (79%) and long-lasting success in 21 (72%). Three patients underwent emergency coronary surgery to avoid infarction. Dilatation is indicated in patients with disabling angina which jeopardizes their quality of life and with coronary lesions which are proximal, subtotal, concentric and non-calcified.

Angiography↗
PubMed1976

[Reanimation outside the hospital by the mobile intensive care station in Zurich].

Of 502 patients handled by a mobile intensive care unit, 70 were resuscitated: 20 immediately, 9 within 3 min and 41 later than 3 min from onset of cardiac or respiratory arrest. There were 9 temporary and 10 longterm survivors among the 29 patients who underwent resuscitative measures within 3 min of collapse. First-aid training programs in resuscitation methods are a necessary supportive measure to the operation of mobile intensive care units.

Coronary Care Units↗