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Biomedical subjects

J C Kahn

Publications and source records attributed to J C Kahn.

At least 37 records · Page 2Linked to original sources
PubMed1988

[Bepridil and bundle of His block. Apropos of a case].

The first case of atrioventricular block located in His bundle observed during oral treatment with bepridil is reported; the block subsided when the drug was discontinued and reappeared when it was reintroduced. Electrophysiological studies performed with bepridil have shown that, as could be foreseen from its beneficial or undesirable effects, this calcium antagonist has some properties of Vaughan Williams' class I antiarrhythmic agents and alters subnodal conduction. Clinical studies indicate that in therapeutic doses this alteration has little or no significance, but it may reach clinical expression when latent of patient pre-existing disorders of conduction within or below His bundle are present.

Bepridil↗
PubMed1987

Acute hemodynamic effects of intravenous nicardipine in patients treated chronically with propranolol for coronary artery disease.

Intravenous nicardipine, 5 mg, was infused over 5 minutes in 2 comparable groups of 8 patients with chronic coronary artery disease but no clinical signs of heart failure. Eight patients had received no previous treatment and served as a control group; 8 other patients had received long-term treatment with large doses of propranolol. The hemodynamic responses to nifedipine were similar in the 2 groups, but was greater in patients taking propranolol. At 10 minutes, systemic vascular resistance decreased by 47% in patients taking propranolol and by 39% in the control group; mean aortic pressures decreased by 25% and 10%; heart rate increased by 23% and 19%; and cardiac index increased by 45% in both groups. At 20 minutes, left ventricular end-systolic volume index decreased by 20% in patients taking propranolol and 15% in the control patients; angiographic stroke index increased by 19% and 8%; left ventricular ejection fraction increased by 22% and 11%; and mean circumferential fiber velocity increased by 46% and 32%. Intravenous nicardipine infusion (5 mg) did not induce negative inotropic effects in patients with chronic coronary heart disease, and no evidence of congestive heart failure was seen, even in patients receiving large doses of propranolol. Nicardipine counteracted the potential deleterious effects of propranolol; increased peripheral vascular resistance and left ventricular stroke work and decreased cardiac output.

Adult↗
PubMed1987

Could inspiratory apnea disturb left ventricular volume assessment by contrast angiography?

To assess the influence of postinspiratory apnea on the measurement of the left ventricular volumes, contrast ventriculography was performed on 19 patients during spontaneous breathing and then in postinspiratory apnea. Data obtained were similar for end diastolic volumes (81 +/- 29 ml/m2 vs. 83 +/- 25; NS), end systolic volumes (35 +/- 20 ml/m2 vs. 34 +/- 19; NS), systolic index (46 +/- 13 ml/m2 vs. 49 +/- 12; NS), and ejection fraction (0.57 +/- 0.11 vs. 0.59 +/- 0.12; NS). Postinspiratory apnea suppressed the overlapping of the left ventricle with abdominal viscera in 15 of 17 patients. Diaphragmatic immobility permitted the assessment of regional left ventricular function in all 19 patients. However, pressures recorded in inspiratory apnea can no longer be compared to a transmural pressure, and, to assess ventricular compliance, intrapleural pressure must be measured simultaneously. We conclude that left ventricular volume assessment by contrast ventriculography is not disturbed by inspiratory apnea. This maneuver improves the quality of the images and allows a better evaluation of left ventricular segmental function. Spontaneous breathing can be recommended to simplify left ventricular compliance study.

Adult↗
PubMed1987

[Myocardial infarction in Behçet's disease].

A case of myocardial infarction in a 23-year old male patient with Behçet's disease is reported. The infarction occurred 4 years after the onset of the disease, which had been marked by recurrent venous thrombosis. Coronary arteriography showed stenosis of the anterior interventricular artery and occlusion of the first diagonal artery; the other coronary vessels were normal. A search for vascular risk factors, including haemostasis, was undertaken, yielding only moderate cigarette-smoking. About 10 cases of myocardial infarction associated with Behçet's disease have been reported. They concerned young, usually male subjects. Infarction usually occurred late in the course of the disease, and vascular risk factors were seldom elicited. The leukocytoclastic vasculitis of Behçet's disease alone may be responsible for stenosis, thrombosis and false arterial aneurysms, as shown by anatomical studies. The physiopathological mechanisms involved (reduction of endothelial or systemic fibrinolytic activity, rise in fibrinogen and factor VIII) are still unclear; we believe that these abnormalities are inconstant. Behçet's disease may be regarded as a possible cause of myocardial infarction in young subjects.

Adult↗
PubMed1986

Hemodynamic effects of intravenous diltiazem in patients treated chronically with propranolol.

In the search for any deleterious hemodynamic effects of the acute administration of intravenous diltiazem (0.25 mg/kg), in patients on beta blockers, studies were performed in two comparable groups of eight patients with chronic coronary heart disease without clinical signs of heart failure. In the first group, with no previous treatment, the only significant variations observed were a decrease in systemic vascular resistance (p less than 0.01) and an increase in cardiac index (p less than 0.01), which were noted only at 5 minutes. In the second group, receiving long-term oral doses of 120 to 240 mg/day of propranolol, at 5 minutes, despite a slight decrease in peak positive first derivative of left ventricular pressure (p less than 0.05), cardiac index and systolic index increased (p less than 0.05 and p less than 0.01) with decreases in systemic vascular resistance (p less than 0.01) and mean blood pressure (p less than 0.05); at 15 minutes, systemic vascular resistance was still decreased (p less than 0.05) and cardiac index and systolic index were still increased (p less than 0.05). In conclusion, intravenous administration of diltiazem (0.25 mg/kg) to patients with chronic coronary heart disease and no evidence of congestive heart failure, who were receiving propranolol, was safe and prevented, in these patients, the potential deleterious effects of beta blockers, that is, increased peripheral vascular resistance and decreased cardiac output.

Adult↗
PubMed1985

Arteriovenous shunt measured by bolus dye dilution: reproducibility and comparison between two injection sites.

Twenty-eight brachial arteriovenous fistulae (AVF) flows were assessed by the Stewart and Hamilton method by bolus dye injection. These measurements were divided in two groups: a first group with dye injection into the AVF artery and a second group with dye injection into the efferent vessel of the AVF in close proximity. The increase and the decrease of dye concentration were regular and the circulation occurred very late in both groups. Reproducibility was assessed by the usual index: the mean of the differences between two successive measurements of each series related to the first of these two and expressed as a percentage, m(Qn - Qn - 1)/Qn%. In the two groups, the reproducibility index was at 10.1%, similar to the index applied to Grimby's results, measuring successive cardiac output by dye bolus injection at 9.8%. Theoretical criteria of validity of the Stewart and Hamilton method were checked for all measurements. Even when the duration of the measurement was very short, arteriovenous flow fulfilled the criteria of validity in the same way as cardiac output. Two AVF flows were measured successively at both injection sites with no difference between the obtained values. The same reproducibility of the efferent vessel injection site group suggests that an arterial puncture is not necessary for a correct assessment of AFV flow.

Adult↗
PubMed1981

[Left ventricular performance in chronic hemodialysis patients studied during intense exercise and during a dextran infusion test (author's transl)].

In 14 chronic hemodialysis patients with recent circulatory pulmonary congestion or pulmonary edema, left ventricular failure was suspected. Left ventricular function was studied by a sitting exercise test and a dextran infusion test. According to the left ventricular function curves the left ventricular function was not altered in chronic hemodialysis patients compared to normal subjects. It is possible that on average the left ventricular performances is higher in chronic hemodialysis patients than in normal subjects. These results indicate that circulatory pulmonary congestion and pulmonary edema are not reliable signs of left ventricular failure in chronic hemodialysis patients.

Adult↗
PubMed1981

Hemodynamic effects of arteriovenous fistulae in chronic hemodialysis patients at rest and during exercise.

The effects of arteriovenous fistulae (AVF) on cardiac output (CO) and cardiac filling pressures were studied at rest and during exercise in 16 chronic hemodialysis patients. After the occlusion of the AVF, average CO fell but cardiac filling pressures remained unchanged, seven patients had a drop in CO greater than or equal to 1.0 l/min (group A) and nine patients had a drop in CO less than or equal to 0.9 l/min (group B). At rest, average CO was higher in group A than in group B, but cardiac filling pressures were the same in group A and in group B. During maximal exercise, average CO and cardiac filling pressures were the same in both groups.

Adult↗
PubMed1979

[Average steady-state plasma levels with slow release quinidine preparations].

Arabogalactane sulphate of quinidine (AGSQ) is a slow release preparation of quinidine. The aim of this study was to compare the plasma levels of quinidine obtained by different preparations of AGSQ (AGSQ I, II and III) and to determine which was best suited to therapeutics. The "in vitro" study showed different amounts of quinidine liberated in 6 hours, 34% with AGSQ I, 58% with AGSQ II and 100% with AGSQ III. The plasma quinidine levels were studied after administration of a dose corresponding to 330 mg quinidine base, morning and evening for 7 consecutive days to 27 hospitalised patients; 7 received AGSQ I, 11 received AGSQ II 5, received AGSQ III and 4 quinidine sulphate. The delay in reaching a steady state was 24 hours for the quinidine sulphate 36 hours for AGSQ I, 48 hours for AGSQ II and 60 hours for AGSQ III. The average plasma level on the 7th day (Cee) was 2.74 +/- 0.71 microgram/ml, 2.62 +/- 0.74 microgram/ml and 3.29 +/- 0.72 microgram/ml respectively. The plasma quinidine levels were maintained between toxic and therapeutic levels (3,5 and 1,7 microgram/ml) only with AGSQ II by suppressing the peak observed 1 hour administration of quinidine sulphate. An excellent correlation (r = 0,984) was observed between the plasma quinidine 6 hours after ingestion and the Cee. A blood test during the steady state, 6 hours after ingestion of the drug, is useful in adjusting the dosage. These results suggest that AGSQ II is the preparation best suited for therapeutic usage although it does not give the best relative bioavailability of the drug.

Delayed-Action Preparations↗
PubMed1979

Clinical assessment of infarct size by serial determinations of serum creatine phosphokinase activity.

Infarct size (IS) was estimated from serial total creatine phosphokinase (CK) changes in 82 patients with acute myocardial infarction (MI). Anteroseptal and inferior MI involved a relatively small mass of myocardium (16.0 +/- 6.4 and 24.7 +/- 10.0 CK-g-eq respectively); anteroapical and inferoposterior MI had an average IS of 35.9 +/- 15.9 and 32.8 +/- 13.8 CK-g-eq respectively (NS); extensive anterior and inferoposterolateral MI had an average IS of 57.8 +/- 20.1 and 51.1 +/- 11.5 CK-g-eq respectively (NS). Left ventricular failure (LVF) correlated with estimated IS and not with location of the infarct. In patients with an IS ranging from 30 to 50 CK-g-eq, the incidence of LVF was 33%. In patients with an IS greater than 50 CK-g-eq, the incidence of LVF was 65%. Out of the 6 patients who died, 3 had an IS greater than 60 CK-g-eq. 3 groups of patients could be identified from the duration of the CK release time: in group I (mean = 20 +/l h; n = 61), infarct size was highly correlated with peak CK activity (r = 0.93); in group II (mean = 39 +/- 7 h; n = 17) the correlation between IS and peak CK activity was poor (r = 0.59) and might indicate a gradual necrosis; in group III (n = 4) patients with reinfarction showed a second peak on the descending limb of the CK activity curve. Follow-up information was available in 96% of the 76 survivors. At the end of the follow-up (18.1 +/- 10.8 mth) IS was not significantly different in patients with LVF (42.7 +/- 17.5 CK-g-eq) and in those without LVF (34.7 +/- 19.7 CK-g-eq).

Adult↗
PubMed1978

[Patients on chronic hemodialysis. Hemodynamic study at rest and during exercise before dialysis, in hypertensive and normotensive patients (author's transl)].

In twenty chronic hemodialyzed patients a hemodynamic study was carried out just before dialysis at bed rest and during sitting bicycle exercise. At bed rest, cardiac index (mean +/- standard deviation = 5.2 +/- 1.1/mn/m2) and pulmonary wedge pressure (17.4 +/- 6.8 mmHg) were increased. At the highest level performed (60 ou 90 W) cardiac index increased in all patients and reached on average normal values as compared to normal sedentary subjects, but heart rate less increased than in normal subjects during maximum effort. These data suggest that these patients had no patent heart failure. Pulmonary wedge pressure was more increased in hypertensive patients (20.7 +/- 6.7 mmHg) than in normotensive patients (13.3 +/- 4.4 mmHg). Since cardiac index was similarly increased in both groups of patients the higher values of pulmonary wedge pressure in hypertensive patients could be related to either an increase in total blood volume, or a reduction in left ventricular compliance or an increase in cardiopulmonary blood volume.

Adult↗
PubMed1978

Delayed semielective coronary bypass surgery for unstable angina pectoris: clinical follow-up and results of postoperative treadmill exercise.

Eighty patients with continued or repeated episodes of chest pain at rest and transitory ischemic electrocardiographic (ECG) changes were classified as having unstable angina pectoris. Following 10 days of intensive medical therapy, including beta blockade, all unerwent coronary arteriography. Medical treatment completely relieved the chest pain in 43 patients (Group I, 54 percent). In 37 patients (Group II, 46 percent) angina recurred within a week of admission (12 patients) or later (25 patients). Seventeen patients were not operated upon (nine were inoperable, four refused operation, and in four operation was not recommended). Sixty-three underwent saphenous vein bypass grafting either following a month of medical therapy (Group I) or within 24 to 48 hours of recurrent angina (Group II). The over-all operative mortality rate was 1.6 percent (1 patient) and the incidence of peroperative infarction was 11 percent. Of the 62 operative survivors, 71 percent were asymptomatic (mean follow-up period 22 months). The incidence of late operative myocardial infarction was 5 percent. Of 44 operative survivors tested by treadmill ECG, 66 percent had a negative response. Thirteen patients underwent postoperative angiographic evaluation (mean, 19.5 months). The over-all patency rate was 84 percent, and in 92 percent of patients at least one graft was patent. Thus, after stabilization by medical treatment, bypass operation could be performed with a low operative mortality rate and the long-term results compare favorably with those achieved with chronic stable angina.

Angina Pectoris↗
PubMed1977

Clinical and hemodynamic results of intraortic balloon counterpulsation and surgery for cardiogenic shock.

Forty-two patients with cardiogenic shock (CS) secondary to myocardial infarction were treated with intra-aortic balloon pumping (I.A.B.P.). In 14 patients C.S. was associated with ventricular septal defect (V.S.D.) and in four with mitral regurgitation (M.R.) secondary to rupture of the posterior papillary muscle. All patients were resistant to conventional medical therapy. Shock was reversed in 20 of the 24 patients in C.S. without mechanical complications. After 24 to 48 hours of I.A.B.P., cardiax index (C.I.) increased from 1.38 to 2.00 L./min./M2, systolic arterial pressure (S.A.P.) from 83 to 96 mm. Hg, urinary output (U.O.) from 10 to 56 ml. per hour, and pulmonary wedge pressure (P.W.P.) decreased from 22 to 16 mm. Hg. Three patients treated with I.A.B.P. alone survived more than 1 year; of the 13 patients who were balloon dependent, four have undergone emergency surgical procedures and two were long-term survivors. In all patients with mechanical complications, I.A.B.P. resulted in significant clinical and hemodynamic improvement. P.W.P. decreased from 19 to 15 mm. Hg, and U.O. increased from 13 to 38 ml. per hour while S.A.P. remained unchanged. In patients with V.S.D. the pulmonary/systemic flow ratio (P/S) declined from 3.5 to 2.8; in patients with M.R., "V" wave amplitude decreased by 8 mm. Hg. Emergency surgery was performed in 10 patients with V.S.D. and in three patients with M.R. and there were eight long-term survivors (13 to 27 months). It is concluded that I.A.B.P. is an effective means of supporting the circulation in C.S. Of the 42 patients with C.S. treated by combining I.A.B.P. and emergency surgery, 13(31%) were long-term survivors (20 +/- 6 months).

Adult↗
PubMed1977

Posterior rupture of the interventricular septum after acute myocardial infarction: successful early surgical repair.

A patient with a large posterior ventricular septal defect complicating an acute inferior myocardial infarction is reported. Because of medically intractable biventricular failure, temporary circulatory assistance was initiated using intraaortic balloon pumping. Emergency coronary angiography, ventriculography, and subsequent operation were carried out. Operative repair involved closure of the septal defect with the use of a Dacron patch, infarctectomy, and aortocoronary bypass grafting and resulted in long-term survival of the patient.

Acute Disease↗