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Biomedical subjects

Y Hasin

Publications and source records attributed to Y Hasin.

At least 145 records · Page 8Linked to original sources
PubMed1979

Co-existing aortic stenosis and secondary hypertrophic cardiomyopathy manifested by an hourglass left ventricle. Successful treatment with verapamil.

A patient with moderate aortic stenosis had severe hypertrophy and a typical hourglass appearance of the left ventricle. His effort-induced angina and dyspnea responded to treatment with verapamil. We suggest that the aortic stenosis resulted in secondary hypertrophic cardiomyopathy which may be treated by calcium antagonists.

Aortic Valve Stenosis↗
PubMed1979

Electrical and mechanical response in biventricular mechanical alternans.

Mechanical alternans of various degrees is produced by rapid heart rates, slower rates in failing hearts and can be brought about by a single extra systole. It has also been shown that the two ventricles may exhibit different degrees of mechanical alternation. The present study was planned to clarify the possible mechanism inducing this latter phenomenon. For this reason myocardial tension was recorded simultaneously from the two ventricles as well as through a miniature strain gage capable of measuring electrogram and myocardial tension of a small area -- just adjacent to a stimulating electrode. The heart was driven at a steady heart rate through one electrode and very late premature beats were applied at various coupling times at another site through an electrode attached to the miniature strain gage. It was found that the degree of mechanical alternans is markedly different at the sites of measurements in either ventricle. These changes could be related to the time interval elapsed between the application of the electrical stimulus and the occurrence of the mechanical response.

Animals↗
PubMed1979

Echocardiographic aortic root motion in ventricular volume overload and the effect of mitral incompetence.

Echocardiographic aortic root motion in systole was studied in 57 patients: 13 normal subjects, 4 patients with left ventricular (LV) volume overload due to anaemia, 16 patients with mitral incompetence, 13 with aortic incompetence and 11 with mitral stenosis. In normal subjects, patients with mitral stenosis and in patients with LV volume overload, in whom the increased stroke volume was ejected forwards into the ascending aorta (anaemia, aortic incompetence) the amplitude of motion of the posterior aortic wall (vp), the aortic widening fraction (AWF) and total aortic motion (TAM) were increased. In mitral incompetence, however, despite the large increase in total LV stroke index, there was a decrease in vp (P less than 0.01), AWF (P less than 0.001) and TAM (P less than 0.001), and the decrease in aortic motion for a given stroke index was related to the mitral regurgitant fraction, indicating that aortic wall movement in systole depended predominantly on forward ejection of the LV stroke volume. Reduced echocardiographic aortic root motion and widening during systole are useful echocardiographic signs of mitral regurgitation.

Anemia↗
PubMed1978

A new hazard in the use of an external demand pacemaker.

Ventricular pacing by a Medtronic model 5880A external demand pacemaker was shown to be inhibited as long as the metal coverplate of the pacemaker was touched with bare hands. The asystolic periods were induced by a previously undescribed malfunction of the pacemaker, inherent in its structure. This phenomenon occurred when both patient and physician were isolated from any main operated instrument. It could be demonstrated that pacer inhibition was induced by capacitive coupled 50 Hz fields from the environment, activating the sensing mechanism through the metal coverplate. The plastic covered Medtronic model 5840 pacemaker does not have such undesirable characteristics.

Electrocardiography↗
PubMed1978

Transtelephone adjustment of antiarrhythmic therapy in ambulatory patients.

The electrocardiograms of 80 ambulatory patients receiving antiarrhythmic therapy were supervised with the help of a transtelephone monitoring system. The patients used a pocket-size modulator and reported several times daily to the receiving center integrated into the intensive cardiac care unit. The surveillance lasted for 5-28 days during which various drugs in varying dosages were administered to suppress or prevent dysrhythmias. In 94% of the patients, a satisfactory therapeutic achievement was obtained. The transtelephone system provides easy diagnosis, immediate pattern recognition, direct and frequent contact with the ambulatory patient and long periods of follow-up. During this time, the proper antiarrhythmic agent can successfully be defined, its effective dose can safely be determined and unnecessary hospitalization can thus be prevented.

Adult↗
PubMed1978

Ventricular ectopic rhythms due to rapid runaway pacemaker.

A patient initially had syncope due to a runaway pacemaker firing at an unusually rapid rate (30 impulses per second). The ventricular arrhythmia was characterized by numerous ectopic beats, with coupling intervals related to the length of the preceding cycle and runs of ventricular tachycardia with slight variations in the intervals between beats. This case demonstrates the clinical characteristics of a very rapidly firing, low-intensity, ventricular parasystolic focus.

Arrhythmias, Cardiac↗
PubMed1978

Propranolol-induced dysfunction of the sinus node in Wolff-Parkinson-White syndrome.

We report the findings in a patients with the Wolff-Parkinson-White syndrome (type A) who initially had recurrent fainting episodes. It appeared that they were caused by prolonged posttachycardiac depression of the sinus node, which was induced by treatment with propranolol. The possibility of covert dysfunction of the sinus node in patients with Wolff-Parkinson-White syndrome should be considered before commencing therapy with beta-adrenergic blocking agents.

Adult↗
PubMed1977

In vivo atrial excitability and anti-arrhythmic drugs.

The threshold of excitability of the atrial muscle was studied in the in vivo beating canine heart. Unipolar cathodal and anodal strength-interval curves were constructed and found to be dissimilar in shape. It was found that at any interval within the relative refractory period of the atrium, as in the ventricle, there is a wide range of current levels delineated by an upper (TU) and lower (TL) limit of threshold which can stimulate the atrial myocardium. Within these limits the threshold varies spontaneously and can be reduced to TL level by a run of extrasystoles. Such TU and TL curves were repeatedly determined following administration of therapeutic doses of quinidine, procaine amide or lidocaine. It was observed that all three drugs prolonged the refractory period. The TU values increased following each of the drugs, and mostly after quinidine, while the TL curve was less affected by quinidine. It is suggested that the exit block thus produced is the principal mechanism whereby quinidine depresses atrial disrhythmias.

Animals↗
PubMed1976

Diagnostic and therapeutic assessment by telephone electrocardiographic monitoring of ambulatory patients.

The electrocardiograms of ambulatory patients have been monitored over the telephone by staff of the intensive cardiac care unit using equipment in the unit. Telephone monitoring is a useful way of diagnosing transient symptomatic arrhythmias and a reliable aid in supervising the patient's rhythm at the beginning or end of treatment. The doctor has direct contact with the patient at the time of his symptoms so that he can reassure or instruct him. This system costs relatively little in manpower and equipment and permits relatively long periods of follow-up. It is effective, however, only in symptomatic cases in which the rate or rhythm disturbances last long enough to be transmitted. Also important are the negative findings when the patient complains of symptoms and abnormal findings during routine telephone transmissions. Accurate detection of transient ischaemic changes seems to be less reliable, and further technical improvements are required.

Adult↗
PubMed1976

Ventricular rhythms in acute myocardial infarction.

Ectopic ventricular activity in acute myocardial infarction is considered to be benign if it is slow and regular (accelerated idioventricular rhythm), but ominous when rapid (ventricular tachycardia). However, it has been observed in an increasing number of reports that these two types may coexist in the same patient, altering thereby the clinical significance of both. In the present study electrocardiograms were analyzed of 55 patients hospitalized for acute myocardial infarction, in whom idioventricular rhythm occurred. It was found that three major types of ventricular rhythms could be identified: a regular-stable rhythm, an irregularunstable one, and a third variant which was a combination of these two types. The stable ventricular rhythm was self limited and harmless. The unstable and combined types which were characterized by random coupling times and varying interbeat intervals, were frequently associated with re-entrant beats and fast ventricular rates and therefore a potentially ominous prognosis. It is suggested that the Ca++ dependent slow diastolic depolarization may be the mechanism responsible for the unstable ventricular rhythm, and the reasons for this assumption are discussed. A therapeutic approach based on the above considerations is described.

Acute Disease↗
PubMedDate not supplied

Guide wire entrapment during PTCA: a potentially dangerous complication.

The tip of a "high-torque" floppy guide wire became entrapped in a coronary artery during elective PTCA in four patients. In two it was removed through the guiding catheter, in the third an operative intervention was needed in order to free the wire, and in the fourth the remnant was left in situ. Interventional cardiologists should be aware of this potential complication.

Adult↗
PubMedDate not supplied

The effect of insulin and glucagon on systolic properties of the normal and septic isolated rat heart.

Controversy exists in the literature concerning the effects of insulin and glucagon on cardiac muscle contractility, in particular during anoxia, ischemia or sepsis. The purpose of the present study was to determine the effects of insulin and glucagon on the systolic function of the normal and the dysfunctioning septic rat myocardium in the Langendorff preparation. In the normal isolated rat heart, neither insulin nor glucagon exhibited any lasting inotropic effect on systolic function or coronary flow. Sepsis (cecal ligation and puncture) resulted in a dramatic reduction of systolic function to 44% of control animals. All insulin-containing formulations tested improved systolic function in septic hearts by a mean of 85% compared to Krebs and glucose only. However, this improvement did not reach statistical significance compared to the use of Krebs and glucose only. Glucagon at 100 micrograms/l was doing as well as Krebs and glucose alone while at 1 mg/l glucagon was only able to maintain pre-perfusion contractility. Our results suggest that neither insulin nor glucagon seem to possess special inotropic properties for the isolated perfused normal or septic rat heart.

Animals↗
PubMedDate not supplied

Effects of acute iron loading on contractility and spontaneous beating rate of cultured rat myocardial cells.

Cardiac dysfunction is a well known but poorly understood complication of iron overload. We have previously shown that cultured myocardial cells are able to assimilate large amounts of iron. In the present study, the effect of iron on the rate and amplitude of beating in monolayer cultures of rat ventricular myocytes was studied. Iron had negative chronotropic and inotropic effects, both reversible upon washout. The negative chronotropic effect developed earlier and could be reversed by adrenaline. The negative inotropic effect took longer to develop and was completely reversed by caffeine. Elevated [Ca++] also partially restored impaired contractility, while adrenaline or ouabain did not show any significant effect. These results indicate that iron toxicity in cultured heart cells impairs cellular function at both sarcolemmal and intracellular sites.

Animals↗
PubMedDate not supplied

The effects of m-AMSA on rat isolated heart.

m-AMSA (4'[9-acridinylamino]methansulphon-m-anisidide) is a new cytoxic agent now under clinical trial. We used the rat isolated perfused heart model in order to investigate the cardiac effects of m-AMSA. The results of the dose-response study indicate that m-AMSA has an acute moderate negative inotropic effect. The 90% effect (25% decrease in developed force compared to the control) was observed at drug concentration of 1.5 micrograms/ml. The refractory period (as measured by stimuli of twice diastolic threshold intensity) increased progressively as the drug concentration was increased (up to 2.5 micrograms/ml). Measurements of the strength-duration and strength-interval relationship showed that m-AMSA induced a significant reduction (P less than 0.005) in excitability and prolongation of refactoriness. We suggest that m-AMSA has a membranal cardiotoxic effect in addition to its known intracellular cytotoxic effect.

Aminoacridines↗
PubMedDate not supplied

Age- and gender-related differences in success, major and minor complication rates and the duration of hospitalization after percutaneous transluminal coronary angioplasty.

This report describes the effect of age and gender on the results of balloon angioplasty using current technique and indications. A consecutive group of 2,067 patients who underwent angioplasty at a single institution after 1990 is described. Angioplastic success was 92.2% and similar among men and women and the various age groups. Sixteen patients (0.8%) died, and mortality among women was significantly higher (1.4 vs. 0.6%, p < 0.001). There were no age or gender differences in the rate of Q-wave myocardial infarction and the need for coronary artery bypass. Minor complications such as groin complications (10.5% women, 5.0% men; p < 0.001) and infections (6.4% women, 3.7% men; p < 0.05) were more common in women, and as a result the duration of hospitalization after angioplasty was longer. The length of hospitalization after angioplasty was longer with advanced age, mainly as a result of higher groin complications (p < 0.001), infections (p < 0.01) and renal failure (p < 0.05). We conclude that using current indications and technique, angioplasty can be performed safely with a high success rate. Mortality is higher among women. The length of hospitalization after angioplasty is longer in women and, at advanced age, due to higher rate of minor complications.

Age Factors↗