Audit of ambulatory blood pressure monitoring in the diagnosis and management of hypertension in practice

This study was carried out to ascertain the value of ambulatory blood pressure monitoring (ABPM) in the diagnosis and treatment of hypertension in routine clinical practice. ABPM was performed during the daytime hours in 410 patients believed to be hypertensive after at least three measurements by their physician and one measurement by a nurse in a hypertension clinic. The diagnosis was confirmed in 70% of patients when 90 mm Hg diastolic blood pressure (BP) was used as the upper limit of normal, and 86.3% when 85 mm Hg was used. In 204 patients who were reviewed 5 years later there were 108 on medical treatment. This reduced diastolic pressure from a mean of 100.6 +/- 8.8 to 85.7 +/- 8.8 mm Hg. However, in 30% of patients the diastolic pressure was still above 90 mm Hg. In the 49 patients with isolated clinic hypertension (ICH), who had remained untreated, diastolic pressure increased from 84.0 +/- 4.8 to 88.1 +/- 8.4 mm Hg over the 5 years. In 19 of these the level exceeded 90 mm Hg. ABPM therefore improves diagnostic accuracy and prevents treatment of patients with ICH. This condition, however, requires follow-up since BP tends to rise with time in some patients. The audit also identified patients who had had a suboptimal response to medical treatment.

Lipophilic versus hydrophilic beta(1) blockers and the cardiac sympatho-vagal balance during stress and daily activity in patients after acute myocardial infarction

OBJECTIVE

To compare the effects of a lipophilic and a hydrophilic beta(1) blocker on cardiac sympatho-vagal balance during daytime activity and stress in patients four to six weeks after myocardial infarction.

DESIGN

Randomised, double blind, crossover study comparing the effect of atenolol (50 mg once daily) with metoprolol CR (100 mg once daily) with treatment periods of four weeks.

SETTING

Large teaching hospital.

PATIENTS

50 patients (45 male, 5 female, age range 40 to 75 years), four to six weeks after an acute myocardial infarction.

METHODS

At the end of each treatment period the 24 hour heart rate variability, heart rate variability power spectra during head up tilt and mental stress, baroreflex sensitivity, and exercise performance were evaluated.

RESULTS

During daytime activity and during orthostatic and mental stress, both heart rate and the ratio between the low and high frequency spectral components of the heart rate variability were significantly lower with atenolol. Conversely, there was no difference between treatments in baroreflex sensitivity and resting plasma catecholamines. Exercise duration and peak oxygen consumption did not differ between treatments, but the heart rate during submaximal and peak exercise was significantly lower with atenolol.

CONCLUSIONS

At the doses used in this study, atenolol achieved greater beta(1) adrenergic blockade than metoprolol CR and this was associated with significant inhibition of vagal withdrawal during stress. This suggests that peripheral blockade of beta(1) adrenergic receptors may be more important than central blockade in preventing stress induced vagal withdrawal in patients after myocardial infarction.

Which indexes of filling behavior should be used to characterize left ventricular diastolic function when changes in heart rate and atrioventricular delay occur?

The routine use of the peak early-to-peak atrial velocity, early velocity integral-to-atrial velocity integral, and early velocity integral-to-the total filling velocity integral ratios are limited because they are influenced by heart rate and atrioventricular delay. Hence, we sought to establish whether these ratios could be normalized to account for the differences in cycle length (RR interval) and diastolic filling period when heart rate and atrioventricular delay were altered in 18 patients with programmable dual-chamber pacemakers. We further explored whether these and other parameters of the mitral velocity profile could be used to characterize the mitral filling pattern during isoproterenol and methoxamine infusions-interventions that are likely to change both heart rate and left ventricular filling. The early velocity integral-to-atrial velocity integral and early velocity integral-to-the total filling velocity integral ratios were more sensitive to minor variations in heart rate and atrioventricular delay than the peak early-to-peak atrial velocity ratio. The early velocity integral-to-atrial velocity integral and early velocity integral-to-total filling velocity integral ratios could not be normalized to account for differences in RR interval or diastolic filling period, whereas the peak early-to-peak atrial velocity ratio became less sensitive to changes in heart rate when it was divided by the RR interval, or diastolic filling period, or square root of diastolic filling period. Because the diastolic filling period is affected by atrioventricular delay independent of changes in the RR interval, these ratios were also corrected for the functional cycle length, defined as the interval from R-wave of the electrocardiogram to the end of the diastolic filling period. When corrected for either the functional cycle length or diastolic filling period or square root of diastolic filling period, only the peak early-to-peak atrial velocity ratio became less sensitive to variations in the atrioventricular delay. The ratio of diastolic filling period expressed as a proportion of RR interval or functional cycle length changed significantly when heart rate and atrioventricular delay were altered and did not improve when diastolic filling period was divided by the square root of RR or square root of functional cycle length. However, when the square root of diastolic filling period was divided by the RR interval or functional cycle length, the effects of heart rate and atrioventricular delay were not apparent. Of all the ratios, the ratio of square root of diastolic filling period expressed as a proportion of RR interval or functional cycle length was the most useful to differentiate the confounding effects of heart rate (+/-atrioventricular delay) from the effects of isoproterenol and methoxamine on left ventricular filling. Hence, this ratio appeared to be a heart rate- and atrioventricular delay-independent index of left ventricular diastolic function.

Nitric oxide can increase heart rate by stimulating the hyperpolarization-activated inward current, I(f)

We investigated the chronotropic effect of increasing concentrations of sodium nitroprusside (SNP, n = 8) or 3-morpholinosydnonimine (SIN-1, n = 6) in isolated guinea pig spontaneously beating sinoatrial node/atrial preparations. Low concentrations of NO donors (nanomolar to micromolar) gradually increased the beating rate, whereas high (millimolar) concentrations decreased it. The increase in rate was (1) enhanced by superoxide dismutase (50 to 100 U/mL, n = 6), (2) prevented by the guanylyl cyclase inhibitors 6-anilino-5,8-quinolinedione (5 mumol/L, n = 6) or 1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one (10 mumol/L, n = 6), and (3) mimicked by 8-bromo-cGMP (n = 6) with no additional positive chronotropic effect of SIN-1 (n = 5). The response to 10 mumol/L SNP (n = 28) or 50 mumol/L SIN-1 (n = 16) was unaffected by IcaL antagonism with nifedipine (0.2 mumol/L) but was abolished after blockade of the hyperpolarization-activated inward current (I(f)) by Cs+ (2 mmol/L) or 4-(N-ethyl-N-phenylamino)-1,2-dimethyl-6-(methylamino)pyrimidinium chloride (1 mumol/L). The effect on I(f) was further evaluated in rabbit isolated patch-clamped sinoatrial node cells (n = 21), where we found that 5 mumol/L SNP or SIN-1 caused a reversible Cs(+)-sensitive increase in this current (+130% at -70 mV and +250% at -100 mV). In conclusion, NO donors can affect pacemaker activity in a concentration-dependent biphasic fashion. Our results indicate that the increase in beating rate is due to stimulation of I(f) via the NO-cGMP pathway. This may contribute to the sinus tachycardia in pathological conditions associated with an increase in myocardial production of NO.

Is respiratory sinus arrhythmia a good index of cardiac vagal tone in exercise?

To assess the relative roles of neural and nonneural mechanisms in respiratory sinus arrhythmia (RSA) at rest and during exercise (steady-state supine cycle ergometry at 25% of peak oxygen uptake), we studied 10 healthy men (mean age 21 +/- 1 yr) before (control) and during ganglion blockade (GB) with trimetaphan camsylate (3-5 mg/min i.v.). GB was confirmed by the abolition of the reflex bradycardia in response to intravenous phenylephrine and of the blood pressure rise with the cold pressor test. RSA was calculated from the power of the spectral component of the R-R interval variability centered at the breathing frequency. GB decreased but did not abolish RSA. At rest, this nonneural component of RSA was negligible, accounting for < 1% of the control RSA. During GB, exercise did not affect RSA significantly. However, because control RSA was decreased by exercise, the proportion of nonneural RSA increased by 32% (range from 17 to 75%). These results indicate that as the vagal tone decreases with exercise, an increasing proportion of RSA is due to nonneural mechanisms.

Effect of low doses of scopolamine on RR interval variability, baroreflex sensitivity, and exercise performance in patients with chronic heart failure

OBJECTIVE

To study the effect of transdermal scopolamine on heart rate variability, baroreflex sensitivity, and exercise performance in patients with heart failure and age matched healthy volunteers.

DESIGN

Double blind, randomised, placebo controlled, crossover study.

PATIENTS

16 patients with chronic, stable heart failure due to ischaemic cardiomyopathy (mean (SEM) age 58 (2) years; mean (SEM) radionuclide left ventricular ejection fraction 28 (2)%; New York Heart Association class II-III) and eight age matched healthy controls.

INTERVENTION

Transdermal scopolamine (500 micrograms delivered over 72 h) or a placebo patch was administered for 48 h.

MAIN OUTCOME MEASURES

Indices of tonic and reflex cardiac vagal activity and exercise performance.

RESULTS

In both groups scopolamine produced a reduction in the 24 h average heart rate and an increase in the time domain measures of heart rate variability. Both the incidence and severity of ventricular arrhythmias remained unchanged. Baroreflex sensitivity, evaluated by the phenylephrine technique, increased significantly (P < 0.001) with scopolamine in patients with heart failure (6.22 (2.81) ms/mm Hg) and in healthy volunteers (5.97 (2.20) ms/mm Hg) as did the amplitude of respiratory sinus arrhythmia, computed by autoregressive spectral analysis of 10 min electrocardiographic recordings (319.9 (123.5) and 657.3 (126.6) ms2 respectively, P < 0.001). While exercise performance did not change, heart rate at submaximal exercise was significantly reduced by scopolamine in each group.

CONCLUSIONS

In patients with mild to moderate heart failure low doses of scopolamine increased tonic and reflex cardiac vagal activity. This was achieved without affecting exercise tolerance or the incidence and severity of ventricular arrhythmias.

Prediction of patient responses to antihypertensive drugs using genetic polymorphisms: investigation of renin-angiotensin system genes

OBJECTIVE

To investigate whether the M235T polymorphism of the angiotensinogen (AGT) gene and the insertion/deletion (I/D) polymorphism of the angiotensin-1 converting enzyme (ACE) gene predict blood pressure response to different antihypertensive agents.

DESIGN

Sixty-three patients with untreated essential hypertension were randomly assigned in a placebo-controlled crossover comparison to atenolol 50 mg once daily, lisinopril 10 mg once daily and nifedipine SR 20 mg twice daily, and the effect on blood pressure was assessed by ambulatory blood pressure monitoring (ABPM). In a further 44 patients, placebo-controlled ABPM data were available after treatment with a single agent (atenolol 50 mg once daily in 16 cases and lisinopril 10mg once daily in 28 cases). The change in systolic and diastolic blood pressure achieved by each agent was analysed for association with genotypes at the AGT and ACE gene loci.

METHODS

Polymerase chain reaction (PCR) amplification of genomic DNA from each individual was used to identify the I/D polymorphism of the ACE gene. The M235T polymorphism of the AGT gene was detected by Tth111I digestion of PCR product.

RESULTS

There was no significant association between response to any drug and either the AGT M235T or ACE I/D polymorphisms.

CONCLUSIONS

The large variability between individuals in the observed blood pressure response to these agents cannot be attributed to the polymorphisms analysed at the ACE and AGT loci.

Pitfalls in the interpretation of spectral analysis of the heart rate variability during exercise in humans

The recent use of spectral analysis of the R-R interval variability to assess the autonomic drive during exercise has produced inconsistent results. The purpose of this study was to assess whether the spectral components of the R-R interval variability reflect different mechanisms at rest and during exercise. Autoregressive spectral analysis of the electrocardiographic and breathing signals was performed in 11 healthy young men at rest and during incremental cycle ergometry. The amplitude of respiratory sinus arrhythmia, i.e. the absolute power of the high frequency spectral component, fell at the onset of exercise, consistent with a reduction in cardiac vagal activity. Conversely, the normalized power of the high frequency component, (i.e. the percentage of R-R interval variance due to the respiratory sinus arrhythmia) increased with increasing work rates. The low frequency spectral component of the R-R interval variability, which when expressed in normalized units is believed to reflect cardiac sympathetic activity, was no longer detectable in severe exercise when the adrenergic drive is known to be elevated. In conclusion, autoregressive spectral analysis of the R-R interval variability does not adequately reflect the autonomic changes that occur during incremental exercise. In particular, the evidence indicates that as the cardiac vagal tone falls with increasing levels of exercise, a greater percentage of the residual power of the high frequency component may be due to non-neural mechanisms.

Within-patient correlation between the antihypertensive effects of atenolol, lisinopril and nifedipine

OBJECTIVE

To investigate whether there are definable subgroups of patients with essential hypertension who respond specifically to particular antihypertensive drugs.

DESIGN

Randomized cross-over comparison of the antihypertensive effect of 50 mg atenolol per day, 10 mg lisinopril per day and 20 mg nifedipine retard twice a day. Ambulatory blood pressure monitoring was used to assess the blood pressure level both for recruitment and at the end of each treatment period. The treatment periods lasted 4 weeks and were preceded by 4 weeks of placebo.

PATIENTS

Seventy-two untreated hypertensive patients with a mean age of 52 (SD 8.4) years were recruited from six general practices and from the hospital outpatient clinic. Sixty-eight patients completed the trial.

MAIN OUTCOME MEASURES

To assess the within-patient correlations among the blood pressure responses to each drug and explore the possible role of simple characteristics, such as the initial blood pressure, plasma renin concentration and age, in identifying the responders to a particular drug.

RESULTS

Systolic/diastolic blood pressure fell significantly with each agent (P < 0.001): atenolol reduced it by 16.3 +/- 13.3/9.9 +/- 8.8, lisinopril by 14.8 +/- 15.0/9.4 +/- 9.1 and nifedipine by 11.6 +/- 12.3/6.7 +/- 8.3 mmHg. There was a low degree of correlation between the changes in blood pressure with the three drugs in individual patients. With each drug there was a small percentage (8.9-14.7%) of non-responders. The initial level of systolic blood pressure was weakly correlated with the antihypertensive effect of nifedipine (r = 0.47, P < 0.001) and plasma renin concentration was related to the effect of atenolol (r = 0.32, P < 0.01). Age did not predict the blood pressure response to any agent.

CONCLUSIONS

The low level of the correlation between the blood pressure changes with the three drugs suggests that different mechanisms may be involved in the aetiology of essential hypertension. Plasma renin concentration and the initial level of systolic blood pressure contribute only weakly to the identification of responders to the three drugs.

Low doses of scopolamine increase cardiac vagal tone in the acute phase of myocardial infarction

BACKGROUND

Reduced cardiac vagal tone in patients with myocardial infarction (MI) is associated with a high risk of sudden death. Muscarinic blocking agents in small doses induce a paradoxical increase in cardiac vagal activity in normal subjects. We tested whether low doses of scopolamine delivered transdermally enhance tonic and reflex cardiac vagal activity in patients in the acute phase of MI.

METHODS AND RESULTS

Patients were randomized to a scopolamine (n = 17) or a placebo patch (n = 19) in a double-blind fashion 4.20 +/- 0.18 days after acute MI. Cardiac vagal activity was assessed by testing the arterial baroreflex sensitivity (BRS) using the phenylephrine method and by power spectral analysis of the RR interval variability. Twenty-four hours after scopolamine, we found a significant increase in BRS (from 7.05 +/- 1.21 to 13.99 +/- 2.33 ms/mm Hg, P < .05) and in RR variability, expressed as the mean standard deviation of 512 normal consecutive RR intervals (from 18.09 +/- 2.64 to 31.16 +/- 4.16 milliseconds, P < .05). The amplitude of respiratory sinus arrhythmia, measured by the absolute power of the high-frequency spectral component, was also enhanced (from 62.55 +/- 21.49 to 305.33 +/- 95.68 milliseconds squared, P < .05), whereas the power in the low-frequency spectral component of the RR variability, which results from the interaction between cardiac sympathetic and vagal activity, did not change significantly (from 73.12 +/- 24.44 to 126.46 +/- 44.29 milliseconds squared, P = .93).

CONCLUSIONS

In patients in the acute phase of MI, low doses of scopolamine cause a sustained increase in cardiac vagal tone and improve the autonomic indices associated with mortality.

Ventilation in chronic heart failure: effects of physical training

OBJECTIVE

To assess the effects of exercise training on ventilatory function in chronic heart failure.

DESIGN

Observer blinded random allocation crossover training and detraining trial.

SETTING

Assessment in hospital based clinical laboratory; training home based.

PATIENTS

22 patients with chronic heart failure (New York Heart Association (NYHA) class II or III) recruited from a tertiary referral centre. All finished the study.

INTERVENTION

Bicycle ergometer exercise for 20 minutes a day, five days a week for eight weeks at 70%-80% of maximum heart rate.

MAIN OUTCOME MEASURES

Exercise capacity on graded incremental exercise test, minute ventilation, oxygen consumption and carbon dioxide output.

RESULTS

Peak work load increased from 96 W to 112 W and peak oxygen consumption from 14.1 ml/kg/min to 15.4 ml/kg/min (p < 0.01). At submaximal workloads carbon dioxide excretion (VCO2) and minute ventilation (Vi) decreased significantly (p < 0.05) though oxygen consumption was unchanged. The relation between Vi and carbon dioxide excretion changed: the slope of the Vi to VCO2 plot decreased from 38.6 to 35.3, indicating an improvement in overall ventilary efficiency. The instantaneous carbon dioxide ventilatory equivalent (Vi/VCO2) decreased at submaximal workloads, and reached a lower minimum value after training, indicating that optimum ventilatory performance improved. The exercise capacity of patients was related to the optimum ventilatory performance. It is suggested that this may in part be mediated through changes in skeletal muscles.

CONCLUSION

Exercise training reduces the ventilatory abnormalities in chronic heart failure; thus some of these changes may be due to physical deconditioning.

Effects of mild physical activity, atenolol and the combination on ambulatory blood pressure in hypertensive subjects

OBJECTIVE

To evaluate whether beta-blocker treatment could enhance the effect of a mild physical training programme upon blood pressure.

DESIGN AND METHODS

In 12 hypertensive subjects (mean age: 40.3 years) a prospective randomized Latin square-design trial was performed with three treatments: physical training and placebo tablets; atenolol 50 mg once a day and inactivity; and physical training and atenolol 50 mg once a day.

RESULTS

Training significantly increased maximal ventilatory oxygen consumption (VO2MAX), and there was a decrease in ambulatory diastolic blood pressure (DBP) which did not reach statistical significance. Atenolol alone significantly reduced ambulatory systolic blood pressure (SBP) and DBP. Atenolol alone did not reduce VO2MAX. The combination of training and atenolol resulted in an increase in VO2MAX compared with atenolol alone, but no additional significant fall in blood pressure.

CONCLUSIONS

Atenolol did not enhance the effect of physical training upon blood pressure and had little if any effect upon the training-induced increase in exercise tolerance.

Baroreflex control of stroke volume in man: an effect mediated by the vagus

1. Beat-by-beat changes in cardiac performance in response to arterial baroreceptor stimulation induced by phenylephrine were evaluated by pulsed-wave aortic Doppler ultrasound in eighteen subjects. Stroke distance was used as an index of stroke volume and minute distance as an index of cardiac output; peak velocity was also measured. 2. The sensitivity of the baroreceptor-cardiac reflex was assessed by calculating the slope of the regression lines relating the changes in heart period (R-R interval), peak velocity and stroke distance in response to the rise in systolic blood pressure (SBP) induced by phenylephrine. In ten subjects the experiment was repeated after vagal blockade by atropine. Since the tachycardia induced by vagal blockade could alter the sensitivity of the baroreflex, we compared the results obtained after atropine with those obtained during pacing at similar rates in six subjects with cardiac pacemakers. 3. As R-R interval lengthened in response to the rise in SBP, stroke distance and peak velocity fell sharply. The subjects with a highly sensitive baroreceptor-heart rate reflex showed the greatest fall in peak velocity and stroke distance. The slope of the relationship between R-R interval and SBP for each subject correlated closely with that of peak velocity/SBP (correlation coefficient, r = 0.88) and stroke distance/SBP (r = 0.93) relationships. 4. Atropine virtually abolished all the cardiac reflex changes, despite a considerable increase in SBP induced by phenylephrine. At comparable heart rates achieved by pacing the sensitivity of the baroreceptor-cardiac reflex (calculated from the slopes of the regression lines relating changes in stroke distance and in peak velocity to the rise in SBP) was maintained and was significantly greater when compared to that obtained after vagal blockade. 5. These results show that the stimulation of arterial baroreceptors is accompanied by a fall in the Doppler-derived indices of stroke volume and cardiac output. This response is neural and is abolished by atropine, which indicates that it is mediated through the efferent vagus.

Antihypertensive effect of carvedilol: a preliminary dose-response study

The blood pressure (BP) lowering effect of low doses of antihypertensive agents is not usually explored because of the difficulty in detecting small changes in BP. Since ambulatory blood pressure monitoring in a cross-over trial design can reliably detect differences of 5 mmHg with less than 20 subjects, we have used this technique to assess the dose-response curve of a new beta-blocker, carvedilol. Twenty subjects were enrolled after diagnostic ambulatory BP monitoring had shown a day-time average diastolic BP of over 90 mmHg. Three doses of carvedilol (6.25, 12.5 and 25 mg daily) and placebo were then given double-blind in random order for periods of 4 weeks each. No period effects were detected. The antihypertensive effect was statistically significant at doses of 12.5 mg and 25 mg daily. There was, however, no evidence that 25 mg/day produced the peak effect. The lowest dose (6.25 mg/day) produced a small fall in both systolic and diastolic BP but neither of these were significant. We conclude that doses of 12.5 and 25 mg carvedilol once a day are adequate for the treatment of hypertension.

Use of ambulatory blood pressure monitoring in pharmacological trials

Four factors govern precision in clinical trials with antihypertensive drugs: the magnitude of the differences in BP to be detected; uniformity in the responses to the antihypertensive agents; the accuracy of the diagnosis of hypertension; and the reproducibility of BP measurements. Ambulatory monitoring has an obvious bearing on all these points. Accuracy is needed for the diagnosis of hypertension. In a group of 255 subjects, 34% had 'false hypertension' on the basis of clinic BP measurements. Unless reproducibility of BP estimates is high, clinical trials must include large numbers of subjects if they are to detect modest differences in BP. With ambulatory monitoring the standard deviation of the difference between two BP readings is reduced by 50%. Changes in DBP of less than 5 mm Hg are not clinically relevant. A trial must be able to detect at least this order of difference. With ambulatory BP monitoring, this is achievable using a small number of subjects, whereas with clinic readings large-scale trials are required. Precision in clinical trials must be improved if antihypertensive drugs are to be introduced on the correct dose regimen. Uniformity in the response to antihypertensive agents has been little studied. Yet none of the agents in common use reduces DBP by more than 10 mm Hg in 50% of hypertensive subjects. Non-uniformity of response necessitates the use of crossover design and an accurate estimate of BP.

Angiotensin-converting enzyme inhibition and physical training in heart failure

A total of 12 patients (mean age +/- SEM 63 +/- 2.6 years) with moderate to severe heart failure (ejection fraction = 23 +/- 3.2%) were included in a placebo-controlled crossover trial. Patients were randomly allocated to 4 periods of 6 weeks each: placebo, placebo and physical training, lisinopril 10 mg daily, and lisinopril and physical training. The exercise time increased from 13.6 +/- 0.9 min with placebo to 15 +/- 1 min with training alone, and to 16.1 +/- 0.7 min with lisinopril and training. With lisinopril alone there was a non-significant increase in exercise time, to 14.5 +/- 0.6 min. Improvements in exercise time were accompanied by a similar increase in peak oxygen consumption. Overall, the most significant improvements in symptoms and indices of cardiorespiratory fitness were achieved with a combination of lisinopril and training. Thus physical training is not only a useful adjunct to the existing medical therapy for heart failure, but it may also provide symptomatic benefits in its own right.

Effect of enalapril on left ventricular mass and performance in essential hypertension

The effect of enalapril on left ventricular (LV) morphology and function was studied in 12 hypertensive patients. The subjects were evaluated after 2 weeks of placebo and after 4 months of treatment with enalapril (20 or 40 mg once daily), using M-mode digitized echocardiograms. The drug reduced arterial blood pressure in all patients. Systemic vascular resistance decreased significantly without changes in cardiac output and heart rate. No patient had significant side effects. After treatment LV mass decreased significantly (233 +/- 46 to 204 +/- 37 g, p less than 0.01); the reduction was due to a decrease in septal and posterior wall thickness, without changes in LV diameter. LV systolic function remained unchanged, whereas peak lengthening rate of LV dimension, an index of LV diastolic function, increased significantly (4.05 +/- 1.8 to 5.11 +/- 1.8 s-1, p less than 0.01). After treatment the basal inverse correlation between peak shortening rate and wall stress did not change, the inverse correlation between peak lengthening rate and wall stress became closer and the basal inverse correlation between peak lengthening rate and LV mass disappeared. In conclusion, antihypertensive treatment with enalapril led to a significant regression of LV hypertrophy associated with improvement in LV diastolic performance and no deterioration of LV systolic function.

[Clinical assessment of syncopes]

Syncope is a relatively common clinical problem and causes 1% of hospitalizations. The clinical syndrome is characterized by a sudden reduction of the cerebral flow secondary to a number of conditions that includes benign, self-limited causes and life-threatening arrhythmias. A high percentage of these patients is discharged from hospital without an etiological diagnosis. The purpose of this short review is to present the classification of syncope and suggest the methodological approach to detect the underlying cause. The importance of patient's age and of a cardiovascular etiology as a negative prognostic index is stressed. The most valuable diagnostic tool remains a thoroughly taken clinical history.

The transient global amnesia-migraine connection. Case report

Transient global amnesia is described in two patients suffering from classical and common migraine, respectively. These cases are peculiar in that the amnesic attack was part of the aura in one patient, while it behaved like an accompanying symptom in the other. The close temporal relation between the attacks of transient global amnesia and migraine strengthens the hypothesis of an etiologic role of migraine. The nature of this mechanism could be the cerebral blood flow changes or the neural perturbation which characterize migraine attacks.