Association between carotid artery atherosclerosis and coronary artery disease in young females. Reference to sex hormone profile

BACKGROUND

Atherosclerosis of coronary and peripheral arteries occurs rarely in premenopausal women. It has been postulated that sex hormones protect the vascular wall.

AIM

To evaluate whether ultrasound assessment of the changes in the wall of carotid arteries provides any useful information on the severity of atherosclerosis of the coronary vessels as well as whether the atherosclerotic changes in the wall of carotid arteries are accompanied by oestrogen insufficiency in the premenopausal age.

METHODS

The studied group consisted of 65 regularly menstruating women: 21 with coronary artery disease (CAD) revealed by angiography or after myocardial infarction (mean age 44 years)--the CAD group; and 44 healthy woman (mean age 43 years)--the control group. The severity of atherosclerotic changes was determined based on computer-assisted measurement of the intima-media complex thickness (IMC-T) in the common carotid artery. In all women prospective measurement of sex hormone profile was done with enzymatic immunoassay: oestradiol at day 7-9 and day 19-21 of the menstrual cycle and follicle-stimulating hormone (FSH).

RESULTS

The IMC-T value was greater in the CAD group than the control group (0.696+/-0.124 mm and 0.518+/-0.064 mm respectively, p=0.001). The IMC-T (>0.6 mm) was a good indicator of the occurrence of CAD (OR 15.6, 95% CI 3.65-71.1, p <0.0001), with a sensitivity of 73.7% and a specificity of 84.8%. There was a negative correlation between oestradiol level at day 19-21 of the menstrual cycle and IMC-T (r=-0.28, p=0.05).

CONCLUSIONS

The IMC-T value >0.6 mm was found to be a sensitive and specific ultrasound parameter that can be useful in detecting the presence of CAD in premenopausal women. The results of the study also suggest a possible association between hormonal profile and early atherosclerotic changes in carotid arteries in premenopausal women.

Intravenous amiodarone for cardioversion of recent-onset atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) is one of the most common causes of hospital admission, with a prevalence of up to 5% of the population, increasing with advancing age. Emergency direct current cardioversion is the therapy of choice when arrhythmia leads to hemodynamic compromise, but in patients who are hemodynamically stable, antiarrhythmic drugs are usually given to restore sinus rhythm.

HYPOTHESIS

The study was undertaken to assess the efficacy of intravenous amiodarone in cardioversion of recent-onset paroxysmal atrial fibrillation (AF). No standard antiarrhythmic therapy has been accepted for pharmacologic cardioversion of AF. Amiodarone seems to be a promising candidate, but only few randomized trials are available and the results are inconsistent.

METHODS

In all, 160 patients with AF lasting < 24 h were randomly assigned (2:1 fashion) to the amiodarone group (n = 106) receiving 5 mg/kg as a 30 min intravenous (i.v.) infusion, followed by i.v. infusion of 10 mg/kg during 20 h diluted in 1000 ml of 10% glucose with 20 IU of rapid-action insulin, 80 mEq of potassium chloride, and 8 g of magnesium sulphate (GIKM), or to the control group (n = 54) receiving 1000 ml of GIKM alone. Treatment was continued up to 20 h independent of sinus rhythm restoration.

RESULTS

Sinus rhythm was restored 20 h after initiation of therapy in 88 (83%) patients in the amiodarone group and in 24 (44%) patients in the control group (p < 0.0001). The difference between efficacy of the two treatment modalities became significant already after 8 h of therapy (53 vs. 14 patients with sinus rhythm, respectively, p < 0.05). The mean dose of amiodarone administered until sinus rhythm restoration was 740 +/- 296 mg. The presence and the type of underlying heart disease did not influence the conversion rate in either group. In two patients (1.8%) treated with amiodarone, the return of sinus rhythm was preceded by asystole.

CONCLUSION

Amiodarone is effective in the termination of AF lasting < 24 h. It may be particularly useful in patients with organic heart disease in whom class I antiarrhythmic agents may be contraindicated. During treatment, the heart rhythm should be monitored continuously.

Risk factors of atherosclerosis in premenopausal women with a sense of well-being. A pilot study

INTRODUCTION

Women before menopause are thought to be relatively safe from cardiovascular disease due to the protective effects of oestrogens, although one may question this opinion with regards to women with many typical risk factors. However, because of the shortage of data concerning prevalence of risk factors in young women, it is not known whether this phenomenon is confined to a limited group or affects many women.

AIM

The purpose of this study was to determine the prevalence of either typical risk factors of atherosclerosis or emotional disturbances that might increase the probability of coronary artery disease in young women.

METHODS

The study group involved 62 premenopausal women with a sense of well-being (regular menstruations, activity of serum follicle stimulating hormone < 15 IU/L). Mean age of women was 43.5 years. Total cholesterol, LDL and HDL fractions, triglyceride, lipoprotein (a) and homocysteine concentrations were examined and body mass index was calculated. A psychological examination assessing depression and neuroticism intensity was also performed.

RESULTS

Total cholesterol concentration (mean values +/- SD, expressed as mg%, percentage of abnormal results are given in brackets) was 206.3+/-35.8 (67.2), LDL cholesterol 124.3+/-30.2 (55.1), HDL cholesterol HDL 62.5+/-14.8 (6.9), triglyceride 101+/-60.1 (13.8), lipoprotein (a) 18.9+/-17.5 (44.8). Body mass index was 25.2+/-4.1 (41.3). History of smoking was positive in 27.4% and 6.5% of examined women had arterial hypertension. Coexistence of 4 to 5 aforementioned risk factors was noted in 27.4% of studied subjects. Mean homocysteine concentration was 10.7+/-2.1 micromol/L, while 41.3% of subjects had levels above the threshold of 11 micromol/l, commonly considered pathological. Symptoms of depression and neuroticism were seen in 30.5% and 22.5% of women, respectively.

CONCLUSIONS

This pilot study of young women demonstrated that, in contrary to popular belief, this population is vulnerable to cardiovascular disease due to high prevalence of many risk factors.

Prognostic value of exercise-induced QT dispersion in patients after acute myocardial infarction

BACKGROUND

Electrocardiographic exercise tests are widely recommended for patients before discharge after myocardial infarction, what justify the search for new variables which may improve their prognostic value. QT dispersion in 12 lead ECG reflects the heterogeneity of ventricular repolarisation. Increased QT dispersion is a noninvasive marker of ischaemia and electrical instability.

AIM

Evaluation of the prognostic value of exercise-induced changes of QT dispersion in patients after an acute myocardial infarction.

METHODS

Heart rate limited treadmill exercise test according to modified Bruce was performed 14+/-5 days after infarction in 77 patients (age 56+/-11,8 female). QT dispersion was measured at rest and on peak exercise. Patients were followed up for mean 88 months.

RESULTS

QT dispersion was higher at peak exercise in those patients who died due to cardiovascular causes (n=8) or suffered from non-fatal myocardial infarction during follow-up (n=15), than in remaining group (71+/-20 vs 58+/-22 msec, p<0.01). At rest QT dispersion was similar in both groups (64+/-17 vs 66+/-20 msec, NS).

CONCLUSIONS

The lack of an exercise-induced decrease in QT dispersion identifies a subgroup of patients after myocardial infarction with a poor long-term prognosis.

Low serum triiodothyronine in acute myocardial infarction indicates major heart injury

AIMS

In patients with acute myocardial infarction (MI), low serum triiodothyronine (T3) concentration is commonly associated with a severe clinical course. The aim of this prospective study was to investigate whether a severe clinical course in patients with low T3 is related to the magnitude of myocardial injury assessed by echocardiography.

METHODS AND RESULTS

Out of 635 patients with MI we enrolled 100 consecutive patients. They were divided in two subgroups: group A, 81 patients without clinical hard events (death, resuscitation following ventricular tachycardia/vertricular fibrillation, new MI) and group B, 19 patients in whom at least one of the above hard events occurred during hospital stay. Thyroid function tests were performed on day 1, 4 and 7, echocardiographic examinations measuring asynergic area (AA), and wall motion score index (WMSI) between day 1 and 5 (median 3). A negative correlation was found between plasma free triiodothyronine (FT3), concentration and AA (p<0.001), FT3 and WMSI (p<0.001) values at all time points. FT3 concentration was lower in group B than group A at all time points (p<0.001).

CONCLUSIONS

In patients with acute MI, low FT3 state is related to the extent of myocardial damage.

L-arginine supplementation prolongs exercise capacity in congestive heart failure

BACKGROUND

In congestive heart failure (CHF), endothelial dysfunction may contribute to impairment of exercise induced vasodilatation and decreased exercise capacity. We hypothesised that administration of L-arginine, a precursor of nitric oxide (NO) and postulated antioxidant, may improve endothelium-dependent vasodilatation and exercise capacity and also exert antioxidant activity.

AIMS

To investigate the effect of oral supplementation with L-arginine on exercise capacity and markers of oxidative stress in patients with mild to moderate CHF.

METHODS

The study had a randomised double-blind cross-over design. Twenty one patients with stable NYHA II-III CHF underwent three exercise tests: initially, after oral administration of L-arginine (9 g/day for 7 days) or placebo. Blood was sampled prior to each test for plasma lipid peroxides, reduced sulphydryl groups and leukocyte oxygen free radical production.

RESULTS

We found a higher prolongation of exercise duration time after L-arginine than after placebo (99+/-106 vs 70+/-99 s, p<0.05). There were no significant differences in markers of free radical activity.

CONCLUSIONS

In patients with chronic stable CHF, oral supplementation with L-arginine prolongs exercise duration which may be due to NO-induced peripheral vasodilatation. The antioxidant properties of L-arginine have not been confirmed in this ex vivo study.

Lipid profile during the first 24 hours after myocardial infarction has significant prognostic value

AIMS

A high level of total cholesterol and LDL-cholesterol disturbs the endothelial function. Thus it can be expected, that hypercholesterolaemia may unfavourably influence the course of the acute myocardial infarction. The aim of the study was to check whether patients with lipid levels above normal during the first hours of myocardial infarction have an unfavourable clinical outcome.

METHODS AND RESULTS

The study group consisted of 348 patients (216 males, aged 65.7+/-12 years) with acute myocardial infarction hospitalized up to 24 hours after the onset of symptoms. Blood samples for lipid profile were taken on the first day of hospitalization, in the morning, while fasting. 109 (31%) patients had a complicated in-hospital course of infarction (i.e. death, recurrent ischaemia, serious arrhythmias and/or conduction disturbances, heart failure). The total cholesterol and LDL-cholesterol levels were higher in the patients with complicated than in the patients with uncomplicated clinical course of infarction: 243+/-40.7 vs 211.2+/-40.6 mg/dl, p<0.001 and 156+/-35.0 vs 132.6+/-35.2 mg/dl p<0.001, respectively.

CONCLUSIONS

Higher levels of total cholesterol and LDL cholesterol during the first 24 hours of acute myocardial infarction have a strong negative prognostic value, what suggests the use of statins as early as possible in acute myocardial infarction.

Acute coronary syndrome: potassium, magnesium and cardiac arrhythmia

BACKGROUND

Cardiac arrhythmia is often present in patients with acute coronary syndrome (ACS) and may be due to the electrolyte imbalance.

AIM

To assess the prevalence and clinical significance of electrolyte imbalance in ACS.

METHODS

Serum potassium and magnesium levels were measured within the first few hours in 204 consecutive patients with ACS admitted to our department over a period of 23 months. Cardiac arrhythmia was documented using continuous ECG monitoring, telemetry or standard ECG.

RESULTS

Hypokalemia was observed in 34% of patients, and was significantly associated with the occurrence of life-threatening ventricular arrhythmias (26% of patients with potassium level <4 mmol/l vs 11.9% of patients with normokalemia, p<0.001). No relationship was found between potassium level and supraventricular arrhythmias or in-hospital mortality. Decreased magnesium serum concentration was found in 22% of patients but was not significantly associated with cardiac arrhythmias or mortality.

CONCLUSIONS

Hypokalemia and hypomagnesemia are often present in patients with ACS. The former is associated with dangerous ventricular arrhythmias. Early assessment of electrolyte serum concentration is needed in order to implement proper supplementation.

Is preinfarction angina associated with better outcome after myocardial infarction?

BACKGROUND

In a clinical setting of acute myocardial infarction (MI), short-lasting and transient anginal pain, preceding the development of acute MI, is regarded as a symptom representing ischaemic preconditioning. Some experimental and clinical data suggested that preinfarction angina may favourably influence the course of acute MI.

AIM

We sought to examine the hypothesis that preinfarction angina occurring within 24 hours prior to the onset of acute MI favourably influences the outcome.

METHODS

The study group consisted of 331 patients who were admitted to our hospital due to acute MI with ST segment elevation with a symptom duration <12 hours and received thrombolysis. Preinfarction angina within 24 hours prior to MI was present in 80 patients whereas the remaining 251 patients had no chest pain preceding acute MI. The course of the in-hospital phase of MI (mean 15 days) was analysed.

RESULTS

In patients with preinfarction angina the in-hospital complication rate was significantly lower than in patients without angina preceding acute MI (p<0.001). Patients without preinfarction angina more frequently developed heart failure (p<0.001) or died (p<0.01) in hospital. Patients with preinfarction angina had significantly less extensive MI and had reperfusion symptoms more frequently. Multivariate analysis showed that there were three factors which independently favourably influenced survival: preinfarction angina (p=0.01), age < or =65 years (p=0.04) and duration of chest pain during acute MI < or =3h (p=0.03). Of the analysed group, 73 patients died in hospital. The independent variables predicting death included prior MI (p=0.04), history of diabetes (p=0.02), acute left bundle branch block (p=0.01) and age >65 years (p=0.03). Non-fatal re-infarction complicated the in-hospital course of MI in 27 patients. The independent variables which predicted this complication included age >65 years (p=0.03) and hypercholesterolemia (p=0.04).

CONCLUSIONS

Patients with preinfarction angina, occurring within 24 hours of acute MI, have better in-hospital outcome and less extensive myocardial injury than patients without antecedent angina. These results may be attributed to the protective effects of ischaemic preconditioning.

Antioxidant vitamins decrease exercise-induced QT dispersion after myocardial infarction

BACKGROUND

Antioxidant vitamins C and E inhibit neutrophil-mediated production of free radicals in acute myocardial infarction (MI) which may limit MI size and improve myocardial perfusion.

AIM

To examine whether treatment with vitamin C and E reduces inhomogeneity of repolarisation in patients with acute MI.

METHODS

In this double-blind, placebo-controlled randomised trial 37 patients with acute MI were enrolled and assigned to vitamin C and E (600 mg/day each) or placebo treatment, starting on the first day of acute MI and lasting for 14 days. Inhomogeneity of repolarisation was assessed by examining QT interval dispersion (QTd), measured both at rest and at the end of sub-maximal exercise test, performed before discharge.

RESULTS

Baseline QTd was similar in both groups, however, exercise-induced QTd was significantly lower in patients treated with antioxidant vitamins compared with the placebo group (59 +/- 20 msec vs 74 +/- 24 msec, p<0.05).

[Hypertension and metabolic syndrome in population of one company. Monotherapy with amlodipine and doxazosin]

In Poland diagnosing of hypertension (HA) and the efficacy of treatment of this condition is still insufficient. Consideration of the concomitant metabolic disorders may help to choose the best line of therapy.

AIM OF THE STUDY

To determine the incidence of HA and concomitant lipid and carbohydrate metabolism disturbances in population of one company. To assess the efficacy of monotherapy of HA and the influence of therapy on some metabolic parameters.

METHODS

The blood pressure was measured in 599 subjects. Patients with HA (> or = 140/90 mmHg) were treated according to metabolic parameters. Patients with fasting total cholesterol (TC) > or = 200 mg% and/or fasting glucose level > or = 110 mg% received doxazosin (D); initial dose 1 mg. The remaining patients received amlodipine (A); initial dose 5 mg.

RESULTS

HA was found in 154 patients (27.5%). In this group, 50 of subjects were unaware of the disease, the remaining 67 (44%) were not treated or treated insufficiently. Elevated glucose and/or TC levels were found in 51% of hypertensives. After one month of treatment with A or D, the mean systolic and diastolic blood pressure decreased significantly (p = 0.001). Monotherapy was effective in 88.9% of subjects in group D and in 92.1% in group A. In group D, TC concentration decreased by 9.5% comparing to baseline (p = 0.001). The tolerance of treatment was similar in both groups.

CONCLUSIONS

One fourth of the examined company population under medical attention of the local health service had HA. One third of HA patients were unaware of the disease. The half of patients with HA had metabolic disorders. Doxazosin and amlodipine were equally effective and well tolerated during one month of treatment. Treatment with doxazosin positively influenced the metabolic profile.

QT interval dispersion in ventricular beats: a noninvasive marker of susceptibility to sustained ventricular arrhythmias

Increased QT dispersion (QTd) calculated from sinus beats has been shown to identify patients prone to sustained VT. However, predictive accuracy of this parameter is limited. Electrophysiological properties of the myocardium may be altered by a premature ventricular beats, which is a well-established trigger for sustained VT. Therefore, the author hypothesised that QTd in spontaneous or paced ventricular beats may improve identification of patients with inducible sustained VT. In 28 consecutive patients (men, mean age 61 +/- 13 years) who underwent programmed ventricular stimulation, the values of QTd calculated in sinus and ventricular beats were compared between inducible and noninducible patients. The mean QTd values obtained using three different methods differed significantly, QTd in paced ventricular beats being the highest, QTd in spontaneous ventricular beats was intermediate, and QTd in sinus beats was the lowest (83.9 +/- 30 vs 63.0 +/- 29 ms vs 53.9 +/- 27 ms, P < 0.0001 and P < 0.004, respectively). In 13 (46%) patients sustained VT was induced. QTd values were significantly higher in inducible than noninducible patients (QTd sinus beats: 67.5 +/- 31 vs 42.1 +/- 11 ms, P = 0.02; QTd spontaneous ventricular beats: 79.3 +/- 35 vs 46.7 +/- 13 ms, P = 0.008, and QTd-paced ventricular beats: 104.8 +/- 32 vs 65.9 +/- 9 ms, P = 0.0009). The receiver operator characteristic curves showed that at a sensitivity level of 100%, the highest specificity for identification of inducible patients had QTd measured in paced ventricular beats (87%) followed by QTd in spontaneous ventricular beats (45%), and QTd in sinus beats (40%). In conclusion, (1) QTd in ventricular beats is greater than in sinus beats, and (2) QTd calculated from paced ventricular beats identifies patients with inducible sustained VT better than QTd measured during sinus rhythm.

Effects of intravenous amiodarone on ventricular refractoriness, intraventricular conduction, and ventricular tachycardia induction

AIMS

Intravenous amiodarone has recently emerged as an important drug for the acute treatment of ventricular tachyarrhythmias. However, electrophysiological actions and the efficacy of the drug in the suppression of ventricular tachycardia inducibility have not yet been fully established. The present study was designed to address these issues.

METHODS AND RESULTS

The study group consisted of 18 patients (all males, mean age 75 +/- 14 years), who underwent electrophysiological study due to a history of sustained ventricular tachyarrhythmia or syncope with non-sustained ventricular tachycardia detected on ambulatory ECG monitoring. The effects of 5 mg.kg(-1) or 10 mg.kg(-1) of intravenous amiodarone on (1) ventricular refractoriness (QTc interval, right ventricular effective refractory period and monophasic action potential duration), (2) intraventricular conduction (paced-QRS and signal-averaged QRS duration), and (3) ventricular tachycardia inducibility, were examined. The drug had no significant effect on ventricular refractoriness. However, a relatively small but significant slowing of intraventricular conduction was seen (paced-QRS duration: 182 +/- 27 ms vs 191 +/- 28 ms, P<0.0007; 183 +/- 32 ms vs 195 +/- 33 ms, P<0.0007; and 177 +/- 21 ms vs 192 +/- 24 ms, P<0.003, at the cycle lengths of 600, 500 and 400 ms, respectively). This effect was more evident during extrasystolic beats than during stable pacing (for example, at the cycle length of 600 ms, the magnitude of amiodarone-induced lengthening of QRS duration was 23.9 +/- 17.6 ms vs 9.7 +/- 7.2 ms, P<0.009, respectively). Intravenous amiodarone did not prevent induction of sustained ventricular tachycardia in any of five patients inducible at baseline. Of six patients with non-sustained ventricular tachycardia, five had sustained ventricular tachycardia or fibrillation induced after amiodarone infusion.

CONCLUSION

Intravenous amiodarone does not prolong ventricular refractoriness, slows intraventricular conduction and may facilitate inducibility of sustained ventricular arrhythmias.

[Micronized fenofibrate, decreased triglyceride levels, total cholesterol and LDL fractions in serum]

Elevated serum level of triglycerides is a classic indication for fibrates. Micronized fenofibrate is hypolipemic drug with proven safety and efficacy in a view of triglycerides reduction, but according to few papers published so far on the subject is also effective in decreasing elevated total and LDL cholesterol. The aim of study was to confirm results obtained from these few previous studies. Forty seven persons with lipid disturbances (25 males and 22 females, age range 34-71 yrs. mean 48.0) entered the study. Thirty two patients had a history myocardial infarction and fifteen persons without clinical symptoms of heart diseases. All of them were treated with micronized fenofibrate 200 mg daily. Micronized fenofibrate decreased serum concentration of total cholesterol by 13.4% (p < 0.01), LDL cholesterol by 21.2% (p < 0.001) and triglycerides by 39.5% (p < 0.001) in whole group of patients. Most beneficial effects were obtained in persons with mixed hyperlipidemia: reduction of total cholesterol, triglycerides and LDL cholesterol serum levels was 22.4% (p < 0.01), 52.5% (p < 0.0001), 25.4% (p < 0.01), respectively. In individuals with hypercholesterolemia a reduction of total cholesterol by 11% (p < 0.05) and LDL cholesterol by 15.4% (p < 0.05) was observed. In the group with hypertriglyceridemia or mixed hyperlipidemia reduction of serum triglycerides concentration by 33.5% (p < 0.05) was achieved. No significant change in serum HDL cholesterol level in any group was observed. The treatment with micronized fenofibrate was well tolerated. Our study shows that this drug is safe and seems to be effective in some cases with increased serum total and LDL cholesterol level as well.

Susceptibility to neuromediated syncope after acute myocardial infarction

BACKGROUND

Syncope after acute myocardial infarction (AMI) is a common clinical problem. It may be hypothesised that remodelling and neurohormonal changes following AMI may predispose to neuromediated syncope.

DESIGN

To address this issue we prospectively evaluated the incidence of positive results of head-up tilt-table testing in 40 patients following AMI and 40 age and sex matched controls without a history of syncope. The mechanisms of tilt-induced changes in autonomic tone were assessed using spectral analysis of heart rate variability. The patients were followed-up for one year.

RESULTS

Positive results of tilt-test occurred in 4 (10%) controls and 13 (33%) AMI patients (P = 0.01). No significant differences in sympathovagal interaction (assessed by a low frequency/high frequency ratio) were detected between the groups before tilting (2. 9 +/- 1.9 vs. 3.1 +/- 2.2; NS). However, dynamic changes of this parameter differed significantly during the first 5 symptomless minutes of the active phase of tilt-test. The ratio increased in the majority of controls (87%) and decreased in the majority of patients (62%) (P < 0.0001). During one year follow-up, syncope or presyncope occurred in 10 (25%) AMI patients but did not occur in any control subject (P < 0.001). The sensitivity, specificity and predictive accuracy of an early tilt-test after AMI for the prediction of syncope or presyncope was 70%, 80% and 78%, respectively.

CONCLUSION

Patients after AMI are prone to neuromediated reactions. Sympathetic withdrawal seems to be the most likely mechanism of syncope. The role of tilt testing for identification of patients susceptible to syncope or presyncope after AMI needs further investigation.

Hypomagnesemia in heart failure with ventricular arrhythmias. Beneficial effects of magnesium supplementation

OBJECTIVE

To assess the role of electrolyte imbalance in cardiac arrhythmias associated with congestive heart failure.

DESIGN

Serum magnesium and potassium levels, urine magnesium excretion and the incidence of ventricular arrhythmias were assessed throughout the study. The patients who displayed complex arrhythmias after the first week of hospital medication were randomized 2:1 to double-blind magnesium supplementation or placebo.

SETTING

The study was carried out in one municipal hospital, providing primary care.

SUBJECTS

A total of 588 consecutive patients were screened for eligibility (clinical heart failure >/=6 months; NYHA class II-IV; left ventricular ejection fraction </=40%; sinus rhythm; serum creatinine </=2 mg dL-1). A total of 78 patients entered and 68 patients completed the study.

INTERVENTIONS

Intravenous administration of magnesium (magnesium sulphate 8 g in 250 mL of 5% glucose) or placebo (250 mL of 5% glucose) over 12 h.

MAIN OUTCOME MEASURES

(i) Incidence of ventricular arrhythmias in patients with hypomagnesemia; (ii) effects of magnesium supplementation on ventricular arrhythmias.

RESULTS

On admission, hypomagnesemia was found in 38% and excessive magnesium loss in 72% of patients. Serum magnesium levels were lower and urine magnesium excretion was greater in patients with complex ventricular arrhythmias, both on admission and after treatment for heart failure. Intravenous administration of magnesium caused a significant decrease in the number of ventricular ectopic beats (P < 0.0001), couplets (P < 0.003) and episodes of nonsustained ventricular tachycardia (P < 0.01).

CONCLUSIONS

Hypomagnesemia, probably related to increased urine magnesium excretion, is an essential feature of heart failure associated with complex ventricular arrhythmias. These arrhythmias can be alleviated/abolished by magnesium supplementation.

Low-dose glucose-insulin-potassium is ineffective in acute myocardial infarction: results of a randomized multicenter Pol-GIK trial

We aimed to assess the clinical efficacy of glucose-insulin-potassium (GIK) in acute myocardial infarction. Experimental data provided evidence of the beneficial effects of GIK on ischemic myocardium. The clinical trials, mostly uncontrolled and conducted mainly before the thrombolytic era, were inconclusive due to the small number of patients and discrepancies in protocols. In order to evaluate the efficacy of this intervention, we have performed a prospective multicenter randomized study. The study consisted of 954 patients with acute myocardial infarction (MI) randomized within 24 hours from the onset of symptoms to low-dose GIK (n = 494), which consisted of 1000 mL 10% dextrose, 32-20 U insulin, and 80 mEq K-, or to the control group (n = 460), which was given 1000 mL 0.89% sodium chloride, by intravenous 24-hour infusion at a rate of 42 mL/h. Cardiac mortality and the occurrence of cardiac events at 35 days did not differ between GIK and control-allocated patients (32 (6.5%) vs. 21 (4.6%), respectively; OR 1.45, 95% CI 0.79-2.68, P = 0.20; and 214 (43.3%) vs. 192 (41.7%), OR 1.07, 95% CI 0.82-1.38, P = 0.62). Total mortality at 35 days was significantly higher in the GIK than in the control group (44 (8.9%) vs. 22 (4.8%), respectively, OR 1.95, 95% CI 1.12-3.47, P = 0.01). The excess of non-cardiac deaths in the GIK group may have occurred by chance. Low-dose GIK treatment does not improve the survival and clinical course in acute MI.

Effect of early captopril treatment on blood adrenaline levels in acute myocardial infarction (the substudy of ISIS-4). International Study of Infarct Survival-4

Of patients with acute myocardial infarction eligible for the International Study of Infarct Survival-4, randomized to captopril (n = 30) or placebo (n = 33), the captopril group had a significant decrease in blood adrenaline on day 3 compared with baseline values. Results suggest that suppression of sympathetic activity contributes to the beneficial effects of treatment with angiotensin-converting enzyme inhibitors in the early phase of acute myocardial infarction.

Effect of supplemental oral L-arginine on exercise capacity in patients with stable angina pectoris

A randomized, double-blind, placebo-controlled study in patients with clinical symptoms of stable angina pectoris and healed myocardial infarction (n = 22) has shown that oral supplementation with L-arginine (6 g/day for 3 days) increases exercise capacity (tested on a Marquette case 12 treadmill according to the modified Bruce protocol). Results suggest that the inefficient L-arginine/nitric oxide system contributes to limitation of myocardial perfusion and/or peripheral vasodilation during maximum exercise in patients with stable angina pectoris.

Clinical symptoms of mitral valve prolapse are related to hypomagnesemia and attenuated by magnesium supplementation

Mitral valve prolapse syndrome (MVP) is a frequent disorder characterized by a number of complaints which lessen the quality of life. The pathogenesis of MVP symptoms has not been fully elucidated. Hyperadrenergic activity and magnesium deficiency have been suggested. This study was designed to verify the concept that heavily symptomatic MVP is accompanied by hypomagnesemia and to elucidate whether magnesium supplementation alleviates the symptoms and influences adrenergic activity. We assessed serum magnesium in 141 subjects with heavily symptomatic primary MVP and in 40 healthy controls. Decreased serum magnesium was found in 60% of patients and in 5% of controls (p <0.0001). Patients with low serum magnesium were subjected to magnesium or placebo supplementation in a double-blind, crossover fashion. Typical symptoms of MVP (n = 13), intensity of anxiety, and daily excretion of catecholamines were determined. After 5 weeks, the mean number of symptoms per patient decreased from 10.4 +/- 2.1 to 5.6 +/- 2.5 (p <0.0001), and a significant reduction in weakness, chest pain, dyspnea, palpitations, and anxiety was observed. Increased noradrenaline excretion before and after magnesium was seen in 63% and 17% of patients, respectively (p <0.01). Mean daily excretion of noradrenaline and adrenaline was significantly diminished after magnesium. It is concluded that many patients with heavily symptomatic MVP have low serum magnesium, and supplementation of this ion leads to improvement in most symptoms along with a decrease in catecholamine excretion.

Effects of captopril on ventricular arrhythmias in the early and late phase of suspected acute myocardial infarction. Randomized, placebo-controlled substudy of ISIS-4

The antiarrhythmic effect of oral captopril was studied during the early (day 3) and late (day 14) phase of acute myocardial infarction among 304 patients in a randomized placebo-controlled substudy of ISIS-4. Ventricular arrhythmias (ventricular ectopic beats per hour) occurred significantly less frequently among captopril-allocated patients than among those allocated placebo at day 3 (logarithmic scale: 0.48 +/- 0.8 captopril vs 0.84 +/- 1.3 placebo; P < 0.003) and at day 14 (0.51 +/- 1.0 vs 0.77 +/- 1.3; P < 0.05). The number of patients with frequent ventricular arrhythmias (more than 10 ventricular ectopic beats per hour) was also significantly lower among those allocated captopril at day 3 (7.3% vs 14.4%; P < 0.05) and at day 14 (7.3% vs 14.8%; P < 0.05). These results support the hypothesis that the activation of the renin-angiotensin-aldosterone and sympathetic system may underlie heart rhythm disturbances in acute myocardial infarction, and that early use of converting enzyme inhibitor therapy may ameliorate these disturbances.

Intravenous amiodarone is safe and seems to be effective in termination of paroxysmal supraventricular tachyarrhythmias

BACKGROUND

Paroxysmal atrial fibrillation (PAF) and paroxysmal supraventricular tachycardia (PSVT) leading to hemodynamic compromise are among the most common reasons for admission to the coronary care unit (CCU) and need prompt and efficient therapy. Direct current cardioversion is the therapy of choice, but if found contraindicated or unavailable some antiarrhythmic agents are usually given to restore sinus rhythm. Many of these drugs have obvious limitations, especially in patients with acute myocardial infarction and/or heart failure.

HYPOTHESIS

The aim of the present study was to assess the safety and efficacy of intravenous amiodarone in the acute termination of PAF or PSVT refractory to other antiarrhythmic agents in a large group of patients consecutively admitted to our CCU.

METHODS

In the present study, we evaluated the safety and efficacy of amiodarone given intravenously in 142 consecutive patients with PAF or PSVT lasting < 24 h. In 37% of patients no evidence of underlying heart disease which may have caused arrhythmias were defined. A median of two other antiarrhythmic agents given prior to the first amiodarone injection had been ineffective.

RESULTS

Sinus rhythm was restored in 91 patients (64%) (65% in the PAF group and 61% in the PSVT group). The mean time to rhythm conversion was 5.5 +/- 6.1 h for patients with PAF and 1.2 +/- 1.2 h for patients with PSVT. The mean dose of amiodarone administered up to conversion was 340 +/- 220 mg for PAF and 220 +/- 105 mg for PSVT. Except for transient first-degree atrioventricular block in two patients, no adverse effects possibly related to amiodarone were observed (including proarrhythmia and incidence or aggravation of heart failure symptoms).

CONCLUSION

Amiodarone given intravenously for acute termination of supraventricular tachyarrhythmias is completely safe and seems effective. The results of this study, which is the largest ever made, indicate a need of randomized, controlled trials for the ultimate assessment of the efficacy of amiodarone in this clinical setting.

Lack of effect of amiodarone on survival after extensive infarction. Polish Amiodarone Trial

BACKGROUND

The purpose of this study was to elucidate whether the reduction of mortality with amiodarone after myocardial infarction depended on ejection fraction.

METHODS

The data from the Polish Amiodarone Trial were analysed retrospectively. Patients with acute myocardial infarction and contraindications to beta-blockers were randomized on days 5-7 after admission to receive amiodarone (n = 305) or placebo (n = 308). Short and long-term (46 months) mortality were analysed comparing the groups with impaired (ejection fraction < 40%) and preserved (ejection fraction > or = 40%) left ventricular function. A subset of patients (n = 523) with available echocardiograms were subjected to this analysis.

RESULTS

Long-term and sudden cardiac mortality were significantly reduced with amiodarone in the group of patients with ejection fraction > or = 40% (amiodarone versus placebo, respectively: 9.1 versus 16.5%, P < 0.05; 3.4 versus 8.2, P < 0.05). No beneficial effect of amiodarone was observed in the group with low ejection fraction (cardiac and sudden cardiac mortality: amiodarone versus placebo, 20.8 versus 19.3% and 7.8 versus 5.7% respectively). One-year mortality also revealed a favourable trend only in amiodarone-allocated patients with ejection fraction > or = 40%.

CONCLUSION

Amiodarone decreased long-term and sudden cardiac mortality after myocardial infarction only in patients with preserved left ventricular function. No benefit was observed in patients with decreased ejection fraction.

Effects of antioxidant vitamins C and E on signal-averaged electrocardiogram in acute myocardial infarction

Experimental studies indicate that oxygen-free radicals contribute to ischemic myocardial damage and affect electric properties of cellular membranes. We hypothesize that an association exists between an oxygen-free radical-induced component of myocardial ischemic injury and altered electric function that underlies the genesis of ventricular late potentials in the course of myocardial infarction. If so, antioxidant vitamins C and E may prevent alterations in the signal-averaged electrocardiogram (SAECG). To test this hypothesis, we investigated the effect of supplementation with vitamins C and E on the indices of the SAECG in patients with acute myocardial infarction (AMI). Sixty-one patients with AMI were randomized to receive conventional treatment and vitamins C and E, each 600 mg/day, orally for 14 days (supplemented group, n = 33) or conventional treatment only (control group, n = 28). SAECG was recorded on days 1 or 2 and between days 9 and 13 (mean 10). Serum ascorbic acid, tocopherol, plasma lipid peroxides, and oxygen-free radical production by isolated leukocytes were measured on days 1 or 2 and between days 12 and 14. In the control group, SAECG showed an increase in mean QRS and low-amplitude ( < 40 microV) signal durations, from 99 +/- 10 to 111 +/- 13 ms (p < 0.001) and from 31 +/- 8 to 38 +/- 10 ms (p < 0.001), respectively, and a decrease in the root-mean-square voltage of the last 40 ms of the QRS complex, from 36 +/- 25 to 21 +/- 11 microV (p < 0.002). In vitamin-supplemented patients, all these indices remained unchanged. Oxygen-free radical production by isolated leukocytes was decreased compared with that in controls (p < 0.02). Supplementation was confirmed by elevation of serum ascorbic acid and tocopherol. Results support the hypothesis that in patients with AMI, oxygen-free radical-induced cellular damage contributes to alterations in electric function of the heart as seen on the SAECG.

Exercise producing alterations in the signal-averaged electrocardiogram in patients after myocardial infarction

Late potentials are considered to be a marker for regional slow conduction which might predispose to reentrant ventricular arrhythmias. Since these arrhythmias may be induced by ischaemia it may be speculated that exercise-induced myocardial ischaemia may trigger late potentials. Exercise testing was performed in 53 patients early after myocardial infarction and in 20 healthy controls. Typical 12 lead ECG and signal averaged ECG (SA-ECG) from 12 leads were recorded before and after exercise testing. Changes in filtered QRS (QRS) and low amplitude signal durations, and in the root mean square voltage of the last 40 ms of the QRS complex (RMS40) were analysed. Thirty patients developed ST changes, consistent with transient ischaemia, that persisted during the SA-ECG recording after exercise. There were significant differences between baseline SA-ECG and SA-ECG after exercise in patients with positive exercise tests (QRS, 102 +/- 15 ms vs 114 +/- 15 ms (P < 0.01). LAS, 36 +/- 12 ms vs 42 +/- 11 ms (P < 0.05), and RMS40, 29 +/- 14 microV vs 20 +/- 13 microV (P < 0.01). No differences were observed in SA-ECG parameters in either patients with negative exercise tests or in controls. During follow-up, four patients died suddenly; all four had positive exercise tests and in three of them late potentials were induced by exercise. We conclude, that in post-infarction patients with positive exercise tests SA-ECG parameters deteriorate after exercise. This suggests that exercise-induced ischaemia triggers development of late potentials.

Increase of R-wave in pre-discharge ergometric test after myocardial infarction indicates advanced left ventricular injury, latent serious arrhythmias and worse prognosis

Changes in R-wave amplitude during exercise tests performed soon after myocardial infarction (15-31 days, mean 22) were analyzed in 78 men in relation to left ventricular injury (determined by 2-D echocardiography), ventricular arrhythmias (24-h Holter monitoring) and survival after myocardial infarction. It has been found that in patients with mild left ventricular injury (n = 51, Heger index < or = 3) the sum of the R-wave amplitude in 15 precordial leads recorded immediately after exercise decreased by 3.7 +/- 10% in comparison with resting values. In the patients with major left ventricular injury (n = 26, Heger Index > 3) the sum of R-wave amplitude after exercise increased by 12.9 +/- 17.5% (P < 0.001). Positive linear correlation (r = 0.35, P < 0.01) was observed between the level of left ventricular wall motion disturbances and R-wave amplitude changes. In patients with normal or slightly disturbed cardiac rhythm (n = 42, Lown scale 0-2) the sum of the R-wave amplitude after exercise decreased by 5 +/- 18% as compared to resting values, whereas in the patients with complex arrhythmias (n = 23, Lown scale 3-5) the sum of R-wave amplitude increased amounting to 9.9 +/- 17% (P < 0.001). Out of 17 patients who died during 5-year follow up, 16 displayed an increase or no change of the sum of R-wave amplitude. The same kind of relations between R-wave amplitude changes and left ventricular injury or cardiac arrhythmias were noted in patients with anterior and inferior myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Secondary prevention after myocardial infarction with class III antiarrhythmic drugs

First-year mortality after myocardial infarction (MI) is high, amounting to 15%. It has been well documented that ventricular arrhythmias late after MI constitute a risk factor for sudden cardiac death. Consequently, several authors undertook attempts to decrease post-MI mortality with antiarrhythmic drugs. Unfortunately, the class I drugs most widely used in clinical practice proved to be ineffective or they even increased the risk of death, as occurred in the Cardiac Arrhythmia Suppression Trial (CAST). So far, only beta blockers, although not particularly effective in controlling ventricular ectopic beats, have been found to decrease first-year mortality after MI by 26-36%. Class III drugs appear to be promising in this clinical setting. Early study with sotalol showed a positive, although statistically nonsignificant, trend toward decreasing mortality. In a more recent trial with amiodarone (Basel Antiarrhythmic Study of Infarct Survival [BASIS]) done in Switzerland, total mortality was reduced (p < 0.05). It should be stressed that the drug was administered at a low dosage level (200 mg/day) to 98 patients and did not cause serious side effects. Similarly encouraging results have been provided by the Polish Amiodarone Study. Amiodarone given to 305 patients at a low dose (200-400 mg/day) reduced first-year cardiac mortality by 42% (p < 0.05). No serious side effects were noticed. Several ongoing trials should further substantiate the impact of this regimen on mortality after MI.

Ventricular arrhythmias late after myocardial infarction are related to hypomagnesemia and magnesium loss: preliminary trial of corrective therapy

It has been well established that in acute myocardial infarction (MI) many patients display low serum magnesium (Mg). This is associated with complex ventricular arrhythmias. The question arises whether predischarge arrhythmias occurring late after MI might also be related to Mg imbalance. In 118 patients subjected to heart rhythm 24 h Holter monitoring in the second or third week after MI, we investigated (1) the relationship between serum Mg, urinary Mg loss, and ventricular arrhythmias, and (2) the effect of Mg supplementation on heart rhythm disturbances. In patients with undisturbed rhythm or monomorphic ventricular ectopic beats (VEB) (Lown 0-2; n = 84), mean serum Mg level (mg% +/- SD) was 1.83 +/- 0.21, whereas in patients with multifocal VEB, pairs, or nonsustained ventricular tachycardia (VT) (Lown 3-4; n = 34) serum Mg was decreased to 1.68 +/- 0.27 (p < 0.01). Serum Mg normal range in our laboratory is 1.7-2.6 mg%. The lowest serum Mg reaching 1.55 +/- 0.27 was found in nonsustained VT (Lown 4 b) subgroup (n = 14). Urinary Mg loss measured in 81 patients was more pronounced in those with Lown 3-4 arrhythmias (n = 26) than with Lown 0-2 (n = 55). The daily values were 73 +/- 22 and 54.4 +/- 26 mg, respectively (p < 0.001). Thirteen patients with complex arrhythmias and low serum Mg received Mg supplementation (MgSO4, 8 g in 500 ml 5% glucose intravenously during 24 h). This resulted in restoration of almost undisturbed rhythm in 10 subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Platelet adhesion is related to heart rhythm disturbances in the acute phase of myocardial infarction

This study examines the relationship between platelet adhesion, aggregation and the occurrence of heart rhythm disturbances in 43 consecutive patients (mean age 58) admitted to a coronary care unit with acute myocardial infarction. Blood for platelet studies was taken prior to institution of any medication and heart rhythm was monitored (Holter) for 24 h after admission. The control group consisted of 22 healthy subjects (mean age 55 yr). Platelet adhesion to collagen was measured in EDTA-platelet rich plasma by recording the changes in light transmission in an optical aggregometer. Platelet aggregation was measured by the Born method. Platelet adhesion was increased in the group of patients with acute myocardial infarction as compared to controls and was significantly higher in the patients with complex ventricular arrhythmias (Lown 3-4b, n = 18) than in the patients with stable rhythm. Platelet aggregation in the patients with acute myocardial infarction did not differ significantly from the controls and was not related to heart rhythm disturbances. The causal relationship of increased platelet adhesiveness to collagen and heart rhythm disturbances in acute myocardial infarction remains to be established.

Calcium channel blocker prevents stress-induced activation of renin and aldosterone in conscious pig

A considerable amount of data suggest the involvement of calcium-mediated processes in the activation of the renin-angiotensin-aldosterone (RAA) cascade. To investigate the effect of calcium-channel inhibition on the RAA system, we studied 21 conscious pigs. Blood renin and aldosterone levels increased by subjecting animals to 24 hours of immobilization stress. Renin and aldosterone levels were repeatedly measured by radio-immunoassay in blood samples taken periodically over 24 hours from a chronically implanted arterial cannula. Pretreatment of the animals (N = 11) with nisoldipine, 2 x 20 mg p.o. daily for 2 days before and on the day of immobilization, transiently attenuated the stress-induced increase of plasma renin activity and completely prevented the rise of aldosterone, as compared to nontreated controls (N = 10). The finding that nisoldipine suppresses RAA activation induced by a nonpharmacologic stimulus in the conscious intact animal may have clinical implications.

Stress-induced injury of pig myocardium is accompanied by increased lipid peroxidation and depletion of mitochondrial ATP

The aim of the study was to investigate the mechanisms of myocardial lesions induced by stress in conscious, intact pigs. The animals were subjected to 24 h immobilization, controls were kept in normal conditions. The pigs were killed by electric shock and exsanguination. Lipid peroxidation products: malondialdehyde (MDA), conjugated dienes (CDB), fluorescent end products (RF) and adenine nucleotides (ATP, ADP) were measured in the left ventricular myocardium which was also subjected to histoenzymatic and electron microscopic examination. In stressed animals as opposed to the control group, alterations in ultrastructure and diminution of mitochondrial ATP have been found, together with augmented formation of MDA and CDB reflecting increased free radical generation. These changes may be the component of stress-induced myocardial injury.

[Myocardial infarction pain duration in relation to alterations in homeostasis characteristics of cardiac injury]

Relationship between duration of myocardial infarction pain (MIP) and homeostatic disturbances as well as degree of myocardial injury was investigated. Thirty patients admitted to the Coronary Care Unit during the pain due to progressive myocardial infarction were studied. Patients were divided into two groups according to the duration of pain. First one consisted of subject with pain lasting up to four hours, second group included those whose pain exceeded 4 hours. Following parameters were measured: 24 hours urine catecholamines excretion, serum triiodothyronine and creatinine phosphokinase activity estimated every 6 hours during consecutive two days. We concluded that patients with longer MIP displayed lager thyro-adrenergic and myocardial injury.

Efficacy and tolerance of nisoldipine VS propranolol in patients with essential hypertension

Fifty patients with essential hypertension grade I/II. (WHO) were treated with Nisoldipine (BAY K 5552) or Propranolol for 12 weeks in a single blind, randomised trial. Both drugs similarly reduced mean systolic and diastolic blood pressure. Side effects were rare and usually mild. We conclude that Nisoldipine is safe and effective in the treatment of mild essential hypertension.

Increased activity of circulating polymorphonuclear leukocytes in acute myocardial infarction

Acute myocardial infarction results in an increased sensitivity of circulating polymorphonuclear leukocytes to ex vivo aggregation. This increase was prevented by pretreatment of leukocytes with BW755, but not with aspirin, suggesting that the activation of blood leukocytes in infarction is due to a stimulation of cellular lipoxygenase.

[Cigarette smoking: a main preventable cause of death. The main public health problem of our times]

Cigarette smoking is one of the most important factors endangering the health and life of modern man. Unfortunately the statistics in recent years showed that Poland is now among the countries with the highest consumption of cigarettes in the world. According to the data reported in 1982 by the Polish Anti-tobacco Association our population consists in a great part of habitual smokers, since about 12 million people are smoking cigarettes (over 60% of men and 30% of women). Another diquieting fact is the continuous rise of the proportion of heavy smokers, who smoke over 20 cigarettes daily, which increases many times the health risk.

Effect of nisoldipine on stress-induced myocardial damage in the conscious pig

1. The effect of the calcium channel blocker nisoldipine on the myocardial content of lipid peroxidation products (malondialdehyde (MDA), conjugated double bonds (CDB), fluorescent end-products (RF) and mitochondrial adenine nucleotides) was investigated in conscious pigs (n = 14) subjected to 24 h of immobilization stress. Histoenzymatic and electron microscopic studies of the myocardium were also performed. Nisoldipine was given orally in a twice daily dose of 20 mg for 2 days before and on the day of the experiment. Results were compared with those obtained in immobilized untreated pigs (n = 10) and in non-stressed treated controls (n = 8). 2. Pretreatment with nisoldipine significantly attenuated stress-induced increase in myocardial contents of CDB and RF and prevented decline of mitochondrial adenine nucleotides. Stress-induced myocardial histoenzymatic changes (decrease of succinic dehydrogenase, ATPase, acid phosphatase activity) and ultrastructural alterations (mitochondrial damage, lysis of myofibrils, dilatation of sarcoplasmic reticulum and endothelial swelling) were also diminished. 3. It is concluded that treatment with a Ca2(+)-antagonist is beneficial to the heart exposed to environmental stress.

Platelet aggregation and arrhythmias after myocardial infarction

We investigated the relationship between platelet aggregability and occurrence of complex arrhythmias in 72 males in the third or fourth week after the onset of myocardial infarction. The patients who displayed complex arrhythmias (n = 31), as opposed to those with stable rhythm (n = 41) showed higher platelet aggregability (48 +/- 27% vs 37 +/- 22%, mean +/- standard deviation, respectively, P less than 0.01). No differences were found with respect to plasma free fatty acids and excretion of catecholamines. It is suggested that, after myocardial infarction, increased platelet aggregability may contribute to the development of complex arrhythmias.

Efficacy and tolerance of nifedipine retard vs acebutolol in patients with essential hypertension treated for 26 weeks

Patients with essential hypertension were given calcium channel antagonist, Nifedipine Retard or Acebutolol for 26 weeks in a single blind, randomised trial. Both drugs reduced mean systolic and diastolic blood pressure, but side effects were less frequent and caused less drop-outs in Nifedipine than in Acebutolol group of patients. We conclude that both Nifedipine Retard and Acebutolol were equally effective in essential hypertension but side effects were considerably milder in patients treated with Nifedipine Retard.

Late potentials in the acute phase of myocardial infarction indicate the risk of early ventricular fibrillation

Late potentials occurring at the end of or after the QRS complex were recorded from the body surface by means of a high-gain ECG and the signal-averaging technique in 75 patients, within 24 h from the onset of symptoms of acute myocardial infarction. Late potentials were found in 20 patients (26.7%). Out of this group, eight (40%) developed ventricular fibrillation. There was only one incident of ventricular fibrillation among 55 patients without late potentials (1.8%, P less than 0.001). The three-month mortality after myocardial infarction was slightly higher in individuals with late potentials: 15% vs. 11.5%, but this difference was not statistically significant. We conclude that the presence of late potentials recorded in the acute phase of myocardial infarction indicates a risk of ventricular fibrillation, but this was not associated with an increased mortality rate during the three-month follow-up.

Single-dose i.v. Aldactone for congestive heart failure: a preliminary observation

Aldactone (200 mg potassium canrenoate i.v.) was given in a single dose as the sole drug to 30 patients with congestive heart failure (CHF). Of these patients 21 were unresponsive to routine treatment. Clinical improvement was observed in 18 of 30 patients (60%) within 6 h after Aldactone injection. Good diuretic effect (urine volume over 500 ml/6 h) was achieved in 14 patients, including 7 cases who responded dramatically (diuresis 700-1500 ml in 6 h). Plasma aldosterone concentrations before the injection of Aldactone were variable in individual patients. An analysis of their diuretic response to the Aldactone injection within 6 h showed that responders had significantly higher initial plasma aldosterone level (312 +/- 108 pg/ml) than non-responders (152 +/- 31 pg/ml) (p less than 0.02). The same tendency was observed if good or poor clinical effects were considered. Aldactone caused a slight increase in plasma potassium level (0.20 mEq/1) (p less than 0.025). Aldactone given in a single dose i.v. to patients with CHF is a potent drug and can produce a dramatic response in some individuals who are refractory to routine therapy. The beneficial effects of Aldactone could be seen within the first 6 h especially in patients with secondary aldosteronism.

The renin-angiotensin--aldosterone system and the clinical course of acute myocardial infarction

To determine whether the renin--angiotensin--aldosterone system is stimulated in myocardial infarction, plasma renin activity and serum aldosterone were measured by radioimmunoassay in 95 patients with acute infarction. Urinary catecholamines, and sodium and potassium levels in blood and urine were also determined. Plasma renin activity and aldosterone were insignificantly increased in mild myocardial infarction as compared to a reference group comprising patients with angina pectoris. In patients with a complicated course, however, they were greatly augmented. A close correlation was found between urine catecholamines and plasma renin activity and between urine noradrenaline and aldosterone. Aldosterone values were highly correlated with the urine potassium/sodium ratio.