[The hemodynamics of oral nicardipine determined by radioisotope ventriculography in patients with ischemic cardiopathy]. / Hemodinámica de la nicardipina oral determinada por ventriculografía radioisotópica en pacientes con cardiopatía isquemica.

Hemodynamic effects of nicardipine (60 mg) were evaluated in 20 patients whose left ventricular ejection fraction was less than 55%. Nicardipine significantly reduced the mean arterial blood pressure by 28 mmHg (p less than 0.0005). Left ventricular ejection fraction and maximal rate of ventricular diastolic filling were increased in 12% and 84.0 VDF/s (p less than 0.0005) respectively. The end diastolic volume was reduced by 26 ml (p less than 0.001). The decrease in mean arterial blood pressure correlates with the increase in the left ventricular ejection fraction (r = 0.76, p less than 0.001) as well as with the reduced end diastolic volume (R = 0.43, p less than 0.05). The results obtained corroborate the beneficial effects of nicardipine on ventricular function of ischemic patients, whose cardiac reserve is reduced.

Assessment of a physical training program in patients with myocardial infarction in a tropical country.

Twenty-five myocardial infarction patients, included in a comprehensive cardiac rehabilitation programme, were studied in order to assess the physical training effects upon several physiological parameters in a country with a tropical climate. Training consisted of three-times weekly supervised sessions with running, under telemetric control, accomplished continuously, during thirty minutes at 120 m/min as mean speed. Symptom-limited exercise stress testing was initially performed and repeated after three months of training. 88% of patients showed an increase in physical working capacity, 84% in exercise time duration and 80% in the myocardial efficiency index at subsequent ergometries. A decrease of double product and submaximal heart rate was observed. Angina, ECG ischaemic alterations and arrhythmias during exercise in the first test disappeared or occurred with higher workload in the second ergometry. Mean resting acid concentration, 1.28 +/- 0.36 mmol/l, increased immediately after exercise to 2.03 +/- 0.58 mmol/l. The prescribed physical training programme showed satisfactory results and increased the patients' quality of life, even in a humid and moderately hot climate.

Spontaneous variability and detection of repetitive extrasystoles during simulated acute antiarrhythmic testing.

In order to estimate the reduction in ventricular premature contractions (VPCs) due to spontaneous variability during simulated acute antiarrhythmic testing, and also to determine the detection capacity for repetitive VPCs during short periods of ECG monitoring usually employed as baseline recordings, 2 groups of patients were studied A reduction by more than 50% of the baseline VPC-rate can be expected to occur as a result of an antiarrhythmic intervention, while approximately 40% of the patients with repetitive high risk VPCs escape detection during short periods of control recordings. It is suggested to use a 24 to 47-hour ambulatory monitoring for the diagnosis and classification of VPCs, while acute antiarrhythmic testing should be employed for assessing individual efficacy and tolerance.

Comparison of segmental and global ejection fraction in ischaemic heart disease.

In order to evaluate whether segmental ejection fraction (SEF) is a better index of left ventricular (LV) performance than global ejection fraction (EF), 25 patients with significant coronary stenosis and normal EF were studied. SEF was estimated from the LV cineangiogram after dividing the LV into eight segments by means of a long axis and three equally spaced chords perpendicular to it. The area of a given segment was measured in the end-diastole and the end-systole and SEF was calculated by determining the percent decrease in area for each segment. 12 out of the 25 patients presented hypokinesis, akinesis or dyskinesis of at least two segments; the inferior apical and both diaphragmatic segments were the regions most frequently affected. In 7 patients, these abnormalities were compensated by hyperkinesis of two or three other segments, whereas in the remaining 5 patients contraction abnormalities were not accompanied by hyperkinesis in spite of a normal EF. It is concluded that SEF is a more sensitive index of regional LV function than EF in patients with ischaemic heart disease.

Miocardipatía familiar. Laminario de electrocardiogramas / Familial myocardiopathy. File of electrocardiograms

Se hace un estudio en el Instituto de Cardiología y Cirugía Cardiovascular (ICCC) de la miocardiopatía familiar. Para esto se sigue la evolución de 13 integrantes de una familia y se estudian los trazados de cada uno de ellos. También se presenta un laminario de algunos de sus electrocardiogramas (AU)

Segmental ejection fraction in normal subjects.

Following a modification of the area method described by Gelberg et al., left ventricular regional wall motion was studied in 30 normal subject. The left ventricular cineangiograms were filmed in the right anterior oblique projection at 48 frames/s after injection of 76% sodium-meglumine diatrizoate. The end-diastolic and end-systolic frames were each divided into 8 regions using a grid formed by longitudinal axis, which was traced from the midpoint of the aortic valve to the apex, and three equally spaced perpendiculars to the long axis. Segmental ejection fraction was estimated by determining the percent decrease in each segment area in end-systole with respect to the end-diastolic area. The mean values +/- S. D. obtained for each segment were: anterobasal 58 +/- 14%; anterolateral-proximal 59 +/- 6%; anterolateral-distal 58 +/- 4%; apical-superior 59 +/- 8%; apical-inferior 58 +/- 7%; diaphragmatic-distal 58 +/- 9%; diaphragmatic-proximal 55 +/- 6%; and posterobasal 42 +/- 15%. The values obtained are useful for comparison when evaluating left ventricular performance in patients.

Modification of blood pressure and systolic time intervals by diuretics and beta-blockers in essential hypertension.

Heart rate (HR), blood pressure and systolic time intervals (STI), including total electromechanical systole (QS2), left ventricular ejection time (LVETc), pre-ejection period (PEPc), the PEP/LVET index and the time to the peak of carotid upstroke (Ut), were measured in 24 patients with moderate essential hypertension after 15 days of treatment with oral furosemide (F), hydrochlorothiazide (H), propranolol (P), atenolol (A), furosemide + propranolol (F + P) and hydrochlorothiazide + propranolol (H + P). Except F, all treatments significantly reduced blood pressure; maximal reductions were brought about by A and H + P. The heart rate was most reduced by A. THe QS2c interval was reduced only after F and H, LVETc was significantly reduced by H, A and H + P. Drug combinations prolonged PEPc, while the PEP/LVET index was increased only by H + P. Beta-blockers significantly prolonged the Ut. It is concluded that diuretics shorten QS2c mainly through reduction in blood volume. The H + P combination diminishes contractility and cardiac output and should not be employed in heart failure.

Oral amiodarone in high-risk ventricular arrhythmias.

Oral amiodarone was evaluated in 24 patients with complex forms of ventricular premature depolarizations (VPD) by means of ECG monitoring and measurement of systolic time intervals. The patients received 800 mg daily for 3 days, 600 mg daily for 7 days and 400 mg daily thereafter. Follow-up lasted from 6 to 17 months. Advanced forms of VPD were abolished and the VPD rate was reduced in 98% of patients. After 10 days repetitive VPD were absent in more than 80% and after 4 months more than 70% were completely free from arrhythmia. ECG changes revealed heart rate reduction and prolongation of PR, QRS and QTc intervals. Left ventricular performance was not influenced. After 6 months of treatment, 10 randomly selected patients received placebo instead of amiodarone in a single blind fashion until arrhythmia reappeared; the latter was again abolished by reinstituting amiodarone, The most frequent side effect were corneal microdeposits which were reversible and did not impair vision. It is concluded that amiodarone is effective and well tolerated in patients with high-risk VPD.

Effects of propranolol and atenolol on plasma renin activity and systolic time intervals in borderline hypertension.

Plasma renin activity (PRA) and systolic time intervals (STI), including total electromechanical systole (QS2), left ventricular ejection time (LVET), pre-ejection period (PEP) and isovolumetric contraction time (ICT), were measured in patients with borderline hypertension (n = 23) before and after oral treatment with atenolol and propranolol. Both beta blockers caused a similar fall in blood pressure and heart rate (P less than 0.001). QS2, PEPc and PEP/LVET values did not change after treatment. Propranolol prolonged ICT (p less than 0.001) and reduced LVET (p less than 0.001). No significant changes were detected in PRA after atenolol while a reduction was found after treatment with propranolol (p less than 0.001). No relationship was found between PRA and STI, however a linear correlation was recorded between systolic pressure and PRA (r = 0,91; p less than 0.01) before beta-blockade. These results suggest that: a) only beta 2-adrenoceptors are involved in the release of renin; and b) the effect of beta-blockers on STI follows a reduction of blood pressure and heart rate which in turn affect afterload.

Effects of oral atenolol and propranolol on blood pressure, heart rate and plasma cyclic adenosine 3':5'-monophosphate in borderline hypertensive patients.

The effects of oral treatment with atenolol and propranolol on blood pressure, heart rate and plasma cyclic adenosine 3':5'-monophosphate (cAMP) were studied in a group of young borderline hypertensives. Observations were accomplished after a period of recumbent relaxation and also following physiological stress testing. The latter significantly increased blood pressure, heart rate and plasma cAMP. A direct relationship was found between heart rate and plasma cAMP at rest and also following psychological stress. This relationship was lost following drug treatments. Both beta-blockers significantly reduced all measured variables in both conditions. However, plasma cAMP was most affected by propranolol.

Acute oral antiarrhythmic testing with disopyramide.

Acute antiarrhythmic drug testing with disopyramide was accomplished in 25 patients with frequent ventricular premature depolarization (VPD). Systolic time intervals (STI) were used to assess left ventricular performance. Eighteen patients responded after a loading oral dose of 300 mg disopyramide with 80% or greater reduction in VPD and abolition of advanced grades. Mean onset of drug action was 93 min and the mean plasma level at 2 h was 3.4 microgram /ml. During maintenance therapy 2 of the 18 patients had a relapse, In 2 others, initially protected, VPD recurred during both exercise and psychological stress testing. STI showed increments in pre-ejection period (PEP) and in PEP/ejection time ratio at peak concentrations of plasma disopyramide. Acute tests repeated with placebo in a single-blind fashion in responding patients failed to significantly reduce VPD frequency or grade. Side effects consisted of anticholinergic actions of disopyramide. In 3 patients aggravation of heart failure compelled discontinuation of disopyramide which then remitted.

Enhancement of the antiarrhythmic action of disopyramide by digoxin.

Acute antiarrhythmic testing with 200 mg of disopyramide p.o. was performed in two groups of 15 patients each, with a prevalence of ventricular premature depolarization (VPD) exceeding one per minute. Patients in the first group were not receiving cardiac glycosides; those in the second group were on maintenance therapy with oral digoxin. Systolic time intervals (STI) were recorded throughout the test in order to evaluate left ventricular performance. Plasma levels of disopyramide were measured at peak ECG changes and digoxin levels before and 2 h following administration of disopyramide. Only five patients in the first group responded with an 80% or greater reduction in VPD rate and abolition of repetitive forms. In contrast, 13 digitalized patients responded to disopyramide. Mean plasma levels of disopyramide did not differ in the two groups (1.68 and 1.78 microgram/ml, respectively). Digoxin plasma levels in no case exceeded 3 ng/ml and did not change significantly after disopyramide. Significant increases in STI and in the QTC interval were recorded only in patients of the first group. The PR interval was prolonged in both groups, but to a greater extent in patients receiving digoxin. We conclude that digitalization may prevent myocardial functional depression caused by disopyramide and enhance its antiarrhythmic action.

Influence of post-extrasystolic potentiation on left ventricular function estimated by means of systolic time intervals.

Systolic time intervals were measured in 50 patients with frequent premature ventricular beats. The patients were divided into two groups: group I included those which showed in the beat that preceded an extrasystole a pre-ejection period/left ventricular ejection time (PEP/LVET) ratio greater than or equal to 0.43, and group II with PEP/LVET ratio greater than 0.44. Systolic time intervals recorded during post-extrasystolic potentiation were compared with those measured in the preextrasystolic complex. Also the measured intervals were tested against the hourly rate of premature beats obtained by electrocardiographic telemetric monitoring. The results confirmed the following results of previous reports: a) ventricular premature beats are followed by sinus-potentiated contractions inversely related to the coupling interval and dependent on adequate compensatory pauses; b) potentiated contractions are greater in patients with ventricular dysfunction. No relationship was found between left ventricular performance and the rate of premature beats. It is concluded that the effect of an antiarrhythmic intervention on the left ventricular function might be adequately evaluated by means of systolic time intervals and provoked post-extrasystolic potentiation, with the advantage of using totally non-invasive procedures.

Reversion of supraventricular tachyarrhythmias by means of atrial stimulation.

Thirteen patients with different forms of supraventricular tachyarrhythmia were treated by means of right atrial pacing. Reversion of arrhythmia was obtained in nine out of ten patients with atrial tachycardia or flutter. The remaining three patients, with atrial fibrillation, did not respond to the procedure. The effective pacing rate in converting arrhythmia ranged from 110 to 2400/min, however in five cases it was lower than the atrial rate. The duration of pacing at an effective rate ranged from 20 seconds to 5 minutes in 5 cases, while in the remaining patients it lasted 10 minutes. In two patients the original arrhythmia was converted to atrial fibrillation during stimulation, but in one it disappeared with pacing at 110/min, and in the other, reversion to sinus rhythm occurred spontaneously 4 hours later. No complications were observed. It is concluded that atrial pacing may be useful aid to treat paroxysmal atrial tachycardia or flutter, and can be considered as an alternative procedure whenever there is no response to customary medical treatment or when transthoracic direct current cardioversion is potentially dangerous.

Comparison of the effects of atenolol and propranolol in labile hypertension.

The effects of a single daily dose of 100 mg. of atenolol and an equivalent dose of propranolol were compared during a crossover, 15 day blind trial in a group of young labile hypertensives. Arterial pressure, heart rate, systolic time intervals and the carotid pulse upstroke time, recorded by external non-invasive procedures, were measured before and 4 and 8 hours after the last dose of both drugs. Both beta blocking agents significantly reduced and stabilized the arterial BP and the heart rate to normal values. However, a tendency to return to abnormal values was observed 8 hours after propranolol administration. Both drugs provoked an increase in the pre-ejection period, but with propranolol this increase was related to a larger isovolumetric contraction time, pointing to a negative inotropic action. The carotid pulse upstroke time was increased to normal values with atenolol. Propranolol failed to alter this value. Atenolol in a single oral daily dose is recommended in the treatment of labile hypertension.

Terapéutica de las arritmias cardiacas por el método electroimpulsivo (MEI) / Therapy of cardiac arrythmias by the electroimpulsive method (MEI)

Se presenta un trabajo en el que se plantean el desarrollo histórico, los aspectos científicos, teóricos y prácticos, y la forma correcta de aplicación del método electroimpulsivo (MEI) en la terapéutica de las arritmias cardíacas que, tanto congénitas como adquiridas, tienden agravar la evolución de las cardiopatías y constituyen la causa directa de muerte en muchos casos(AU)

Experimental His bundle escape rhythms.

With the purpose of studying the interactions between sino-atrial (S-A) node and His bundle escape rhythms (HBER), negative chronotropic agents (verapamil, manganese and droperidol) were directly injected in the canine S-A node through its cannulated and autoperfused artery. HBER followed S-A node depression assessed by His bundle electrograms. A well established correlation was found between HBER and S-A node initial rate. His bundle recovery time following an atrial overdrive was 50 times larger than the S-A node recovery time. HBER was found to be more sensitive to sympathetic blockade than to vagal influences. It is concluded that 1) recovery time following overdrive stimulation is a valid index reflecting sinus nodal function; 2) HBER commonly results from selective depression of the S-A node not only depends on rate but also on overdrive suppression; 4) HBER is more sensitive to sympatheticmodulation.