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Biomedical subjects

D A Halon

Publications and source records attributed to D A Halon.

At least 55 records · Page 3Linked to original sources
PubMed1988

Short- and long-term results of angioplasty for multiple coronary stenoses.

Sixty-eight patients underwent percutaneous transluminal coronary angioplasty (PTCA) for multiple coronary stenoses. Lesions involved one coronary vessel in 24 patients, two in 34, and three or more vessels in 10 patients. The primary patient success rate was 96%, and we successfully dilated 162 (91%) of 179 significant (i.e., greater than 70% obstructive) coronary lesions, mean 2.4 lesions/patient. Complete coronary revascularization was achieved in 24 patients (Group 1), while major narrowings were not dilated either by intention or due to failure of dilation in 42 others (Group 2). The clinical state of the patients improved markedly after successful PTCA, and 44 (72%) of 61 were in the New York Heart Association Functional Class I or II 3 to 24 months later. In keeping with the clinical results, there was a significant improvement in treadmill exercise performance, in both groups. Patients with complete revascularization, however, tended to exercise longer (NS) to a greater heart rate (P less than 0.004) with less or no ischemic ST depression on ECG (P less than 0.04). Complications were few and limited to patients undergoing PTCA for unstable angina pectoris or following acute myocardial infarction. One patient (1%) died, two (3%) had Q-wave infarction and one patient sustained a cerebral embolus during catheterization. Restenosis was observed in 6 (29%) of 21 consecutive patients recatheterized 6 to 12 months (or sooner for symptoms) after successful PTCA. Four patients underwent a repeat PTCA, one was referred for coronary artery bypass grafting (CABG), and in one restenosis was minor and symptoms were mild. PTCA should be considered in patients with multiple coronary stenoses in whom all or most of the significant lesions can be dilated. Partial revascularization by PTCA is clinically useful and may be preferable to CABG in patients in whom the surgical risk is increased.

Adult↗
PubMed1988

Advantage of combined therapy with captopril and nitrates in severe congestive heart failure.

We compared the acute hemodynamic effects of captopril and nitrates in 11 patients with severe congestive heart failure and Grade IV cardiac disability. Pressures were measured using a Swan-Ganz catheter system; cardiac output and stroke index were measured by thermodilution, and left-ventricular (LV) volumes and ejection fraction were calculated simultaneously with the hemodynamic measurements from radionuclide ventriculography. Measurements were made in each of four treatment states: control, sublingual isosorbide dinitrate (ISDN) (5 and 15 mg), oral captopril (50 to 200 mg daily) and during combined therapy with captopril and ISDN. Captopril produced a fall in mean arterial pressure (P less than 0.01) from 81 +/- 14 to 72 +/- 13 mm Hg, and a rise in stroke index from 30 +/- 5 to 35 +/- 91/min per m2 (P less than 0.05), while LV ejection fraction increased from 18 +/- 5 to 21 +/- 7% (P less than 0.05). ISDN reduced mean arterial, pulmonary arterial, right-atrial and wedge pressure. The combination of captopril and ISDN produced a greater fall in mean arterial pressure, a further rise in ejection fraction to 22 +/- 8% (P less than 0.05), a fall in systemic (P less than 0.05) and pulmonary vascular resistance (P less than 0.01) and a rise in cardiac (P less than 0.01) and stroke work index (P less than 0.01), while the beneficial effects of ISDN on right-atrial, pulmonary arterial and wedge pressure were again achieved. LV contractility, assessed from end-systolic stress-shortening relations, was essentially unaltered or decreased very slightly. The study showed that combined therapy with captopril and nitrates produced acute hemodynamic benefits superior to those achieved by treatment with captopril or nitrates alone.

Blood Pressure↗
PubMed1987

Golf syncope.

Explore the source record for details and available documents.

Aged↗
PubMed1987

Chronotropic effect of hydralazine and its mechanism of symptomatic sinus bradycardia.

The positive chronotropic effect of hydralazine was studied in 9 patients with symptomatic sinus bradycardia. Hydralazine was given in an intravenous dose of 0.15 mg/kg and heart rate, blood pressure, sinoatrial conduction time (Narula method) and corrected sinus node recovery time were measured. The effect of hydralazine was also studied after total autonomic nervous system blockade using 0.04 mg/kg of atropine and 0.2 mg/kg of propranolol intravenously. In the control state hydralazine produced an increase of 28 +/- 15% (mean +/- standard deviation) in heart rate, and this was essentially due to a decrease in sinoatrial conduction time (by 32 +/- 32%, p less than 0.05). Corrected sinus node recovery time also tended to shorten (decrease of 21 +/- 34%, difference not significant). After total autonomic blockade intrinsic heart rate did not change or increased very little (9 +/- 14%) after administration of hydralazine and there was no consistent change in sinoatrial conduction and corrected sinus node recovery times. The small residual effect of hydralazine on heart rate was related to incomplete autonomic blockade, since the effect of postural change (standing) on heart rate was also not totally abolished. The study showed that the positive chronotropic effect of hydralazine was mainly due to a change in sinoatrial conduction with a smaller change in corrected sinus node recovery time, and the major chronotropic effect of the drug was mediated by the autonomic nervous system.

Aged↗
PubMed1987

Effect of captopril on left ventricular end-systolic pressure-volume and stress-shortening relations in severe cardiac failure.

The effects of captopril on cardiovascular dynamics and left ventricular (LV) contractility were studied in 11 patients with severe congestive heart failure and very poor global LV function. Pressures were measured using a flow-guided catheter, cardiac output by thermodilution, and LV contraction and ejection fraction by simultaneous radionuclide angiography. Ventricular loading conditions were altered by sublingual isosorbide dinitrate to facilitate construction of LV pressure-volume and stress-shortening curves. Captopril decreased mean arterial pressure (p less than 0.02) and systemic vascular resistance, while stroke and cardiac index increased in most patients. Left ventricular ejection fraction increased from 18 +/- 5 to 22 +/- 7% (p less than 0.05), but contractility, assessed from end-systolic pressure-volume and end-systolic pressure-shortening relations, was unchanged or decreased slightly. Heart rate and double product also tended to decrease. In contrast, arteriovenous oxygen difference widened and calculated total oxygen consumption increased during captopril therapy (p less than 0.05). The study showed that captopril improved forward blood flow, total oxygen extraction, and LV ejection fraction following the decrease impedance to LV emptying but not at the expense of an increase in ventricular contractility. This makes captopril an attractive drug for patients with end-stage cardiac failure and a severely damaged myocardium.

Aged↗
PubMed1987

Long term survival and late repair of massive cardiac pseudoaneurysm.

Myocardial rupture of the left ventricle after an acute myocardial infarction resulted in the formation of a massive pseudoaneurysm in a middle aged man. Cross sectional echocardiography was useful in identifying the defect which was successfully closed at operation nine years after its formation.

Echocardiography↗
PubMed1987

Coronary artery to bronchial artery anastomosis in Takayasu's arteritis.

A 27-year-old woman presented with ischemia of the left arm and dizziness together with acute lateral wall myocardial ischemia. Physical examination showed narrowing of the arteries to the head and neck and upper limbs suggesting Takayasu's arteritis. Angiography demonstrated pulmonary and systemic involvement. There was complete occlusion of the right upper lobe pulmonary artery and a large collateral artery from the circumflex coronary artery which anastomosed with the right bronchial artery. This anastomotic channel has not to our knowledge been described Takayasu's arteritis.

Adult↗
PubMed1986

Short-term effect of nifedipine on effort tolerance in patients with angina pectoris.

The short-term effect of oral nifedipine on effort tolerance was tested in 10 patients with effort angina pectoris and a positive effort test (GXT). The patients had four symptom-limited GXTs, using the Bruce protocol, on each day of the study at 0800, 1000, 1400, and 1800 hours. They received four doses of 10 mg oral nifedipine on one day and four doses of placebo on the other, each dose given half an hour prior to each GXT. Values with nifedipine were compared to values with placebo at the same time during each day. Nifedipine improved effort tolerance by 0.5 +/- 0.6 min (p = NS) on the first GXT (mean +/- SEM), by 1.2 +/- 0.6 min (p = NS) on the second GXT, by 1.0 +/- 0.3 min (p less than 0.01) on third GXT, and by 1.3 +/- 0.3 min (p less than 0.01) on the fourth GXT. Improvement of effort tolerance was associated with a fall in resting blood pressure and less ST depression; these changes were statistically significant only on the fourth GXT, which may indicate a cumulative effect of subsequent doses of nifedipine.

Administration, Oral↗
PubMed1985

Can total coronary occlusions be predicted from a previous coronary arteriogram?

We studied the site, severity, and coronary angiographic morphology of coronary lesions and their ability to predict progression of coronary narrowing and obstruction of coronary arteries. Twenty-six patients who had 94 lesions at the time of first angiography were followed for a mean of 29 +/- 17 (SD) months. Progression of disease or obstruction of a vessel occurred in 11 lesions (12%): eight new total obstructions (8.5%) and three subtotal (3%). Narrowings of greater than 75% of the luminal diameter were more likely to become totally obstructed than less severe narrowings (P = 0.01), but three total occlusions occurred at sites where mild disease had been present previously. Lesions in patients with double or triple vessel disease showed a marginally greater tendency to become totally occluded than in patients with single vessel disease (P less than 0.1). We found no relationship between new total obstructions and the angiographic morphology of the lesion (smooth or irregular) nor with its length or position in the artery or the extent of atheroma in the vessel.

Adult↗
PubMed1984

Improvement in regional ventricular function after percutaneous transluminal coronary angioplasty.

We performed atrial pacing and radionuclide ventriculography in 12 patients before and after percutaneous transluminal coronary angioplasty (PTCA). Successful dilatation was achieved in 9 patients while in 3 the procedure was unsuccessful. Atrial pacing before PTCA showed ischemic dysfunction of the region supplied by the narrowed coronary artery. Regional ejection fraction decreased by 36 +/- 12% during rapid atrial pacing, while global left ventricular ejection fraction fell by 11 +/- 7% with a secondary increase in end-diastolic and end-systolic ventricular volume with the onset of ischemia. After successful PTCA, ischemic dysfunction was ameliorated or abolished. Measurements made at identical heart rates showed that both global and in particular regional left ventricular ejection fraction were significantly higher after successful angioplasty and did not fall during the stress of atrial pacing. There was no improvement in regional or global LV function in patients in whom angioplasty was not successful. The study showed that nuclear ventriculography with the stress of graded atrial pacing was a useful method for analysing the immediate results of coronary angioplasty and for studying its effects on regional myocardial function.

Adult↗
PubMed1984

The prevention of cardiac arrhythmias produced in an animal model by the topical application of a phenol preparation in common use for face peeling.

We have shown in an animal model that complex ventricular arrhythmias produced by topical application of a phenol preparation that is used in face peeling can be prevented by a brisk diuresis at the time of application or by gradual application of the phenol preparation. We recommend that continuous cardiac monitoring and recording be performed in patients having topical phenol applications in order to determine the true incidence of cardiac arrhythmias and to ascertain if they are prevented by a forced diuresis, by the gradual application of the preparation, or by a combination of both.

Administration, Topical↗
PubMed1984

The effect of nifedipine on normal and ischemic left ventricular function during atrial pacing stress.

We studied 44 patients (group I: 9 with insignificant disease and group II: 35 with significant coronary artery disease) by nuclear angiography during the controlled increase in heart rate by atrial pacing to evaluate the effect of 20 mg of sublingual nifedipine on left ventricular function. Left ventricular volumes were calculated using count-derived changes: end-diastolic (EDE), end-systolic (ESE), stroke volume (SVE) and cardiac output equivalents (COE) and ejection fraction (EF) and ejection rate (ER) were calculated during basal sinus rhythm (C) and at the maximal atrial pacing (AP) rate with and without nifedipine. In normal subjects, AP decreased ventricular volumes. The administration of nifedipine decreased blood pressure but had no further effect on left ventricular volume. In the ischemic ventricle, AP produced reversible ventricular wall paresis with a smaller decrease in EDE, an increase in ESE and a significant fall in EF. Nifedipine induced a striking improvement in EF and ER. This was probably a consequence of afterload reduction and increased coronary blood flow.

Adult↗
PubMed1983

Localization of lesions in the coronary circulation.

The location of coronary artery narrowings in coronary disease (CAD) is of considerable importance in assessing the mass of myocardium at risk as well as patient prognosis. The detailed distribution of coronary lesions was mapped in 302 patients with CAD who had coronary angiography for chest pain. All identifiable coronary lesions were measured manually and the site and degree of narrowing were stored in a computer-based multisegmental model of the coronary tree. A high prevalence of CAD was found in proximal vessels and especially at, or adjacent to, proximal points of branching. In the left anterior descending coronary artery, the lesions were most prevalent immediately after the first diagonal branch and at the origin of this branch. In the right coronary artery, there was a high prevalence of narrowing between the infundibular and acute marginal branches and specifically around the origin of the right ventricular branch. In the left circumflex coronary artery, there was a predilection for narrowing in and around the origin of the first marginal branch. When a ramus intermedius was present, its origin was frequently the site of narrowing.

Adult↗
PubMed1983

A graphic computerized system for reporting and analysis of coronary angiograms.

A graphic computer based system for coronary angiographic reporting and data storage has been developed. It uses a multisegmental model of the coronary tree so that precise localization of coronary lesions can be made in relation to major branches. The percentage narrowing of the vessel, the length of the lesion, and diameter of the distal coronary vessel can be measured. Collateral vessels, coronary artery bypass grafts, and coronary artery spasm are recorded. The system is simple to use and useful for routine clinical reporting and for detailed analysis of coronary lesions.

Angiography↗