Alternation of left ventricular performance with electrical alternans.

Systolic time intervals (STIs) were measured in a patient with massive pericardial effusion and electrical alternans. The total electromechanical systole and the left ventricular ejection time (LVET) were significantly shorter in beats following the smaller QRS complexes, while the pre-ejection time (PEP) was longer and the ratio of PEP/LVET larger. This beat-to-beat difference in the STIs suggests than an alternation in left ventricular performance accompanied the electrical alternans. After evacuation of the pericardial fluid, electrical alternans and STI alternation disappeared.

Effect of digitalis on diminished baroreceptor sensitivity in diabetics.

The baroreceptor sensitivity was estimated in 50 normal controls (Group A) and in 50 diabetics of comparable age (Group B). The technique used was infusion of angiotensin (0.5 microgram/min) and measurement of the bradycardic response resulting from the increase of blood pressure. The slope was used as an index of baroreceptor sensitivity. Diabetics had significantly lower baroreceptor sensitivity and a higher resting heart rate. Sensitivity decreased with age in both groups. The reproducibility of the method was excellent. Deslanoside-C (0.8 mg) significantly increased the baroreceptor sensitivity in 11 normal controls and 9 diabetics. Very low sensitivity was found in 26 diabetics who had no evidence of orthostatic hypotension, neuropathy, or retinopathy. However all 17 patients with the above findings had very low sensitivity.

[Evaluation of left ventricular function in diabetics by studying systolic time intervals]. / Evaluation de la fonction ventriculaire gauche chez les diabétiques par l'étude des intervalles de temps systoliques.

Systolic time intervals were measured before and four minutes after maximal exercise stress testing in 54 patients without obvious cardiac disease. Twenty seven patients (average age 46 years) had diabetes of over 5 years standing (group II); group I comprised 27 normal controls (average age 46 years). All patients underwent maximal treadmill stress testing using the Bruce protocol and the maximal heart rate was achieved without any signs of coronary insufficiency. No significant difference was observed in the basal systolic time intervals of the two groups. The difference was not significant 4 minutes after the stress test. However, when the changes before and after exercise were compared, the patients in group I had a significant increase in heart rate (p less than 0,001), a reduction in the duration of electromechanical systole (QB2; p less than 0,02) in the preejectional period (PEP; p less than 0,001) and in the PEP/LVET ratio: p less than 0,01, whilst left ventricular ejection time (LVET) remained unchanged. The patients in group II only showed an increase in heart rate (p less than 0,01) and LVET (p less than 0,001). The differences in the systolic time intervals after exercise between these two groups probably reflect a degree of cardiac dysfunction which is not apparent at rest.

[Echocardiography of the communication between the left ventricle and the right atrium. A surgical case]. / Etude échocardiographique de la communication entre le ventricule gauche et l'oreillette droite. A propos d'un cas opéré.

The echocardiographical appearances in left ventricular--right atrial communication are described in a patient who later underwent surgery. Cross-sectional echocardiography was most valuable. It provided an immediate diagnosis and also localised the site of the malformation which had been suggested indirectly by the appearances on M-mode scanning. The success of reparatory surgery was confirmed by the same method.

Constancy of pressure-rate product in pacing-induced angina pectoris.

The pressure-rate product during anginal pain produced by right atrial pacing was studied in 12 patients before, during, and after an angiotensin infusion sufficient to produce a significant rise in blood pressure. During the infusion the pain occurred at a significantly lower heart rate (P less than 0.001). However, the pressure-rate product was similar during anginal pain before and during the angiotensin-induced hypertension and after it wore off. Our studies support the concept that in each individual there is a constant level of myocardial oxygen consumption, as expressed by the pressure-rate product, at which anginal pain occurs.