Role of ambulatory blood pressure monitoring in the assessment and prognosis of patients with borderline hypertension

The role of ambulatory blood pressure (ABP) monitoring in the assessment of mild/borderline hypertension (BHT) is unclear. The aim of this study was to test the hypothesis that measurement of ABP in borderline hypertensives differentiates patients with true mild hypertension from those with isolated clinic hypertension (raised office BP but normal ABP) and that a raised ABP identifies a subgroup who are more likely to progress to and require treatment over 1 year. Consecutive untreated patients with BHT (n = 127, 44 +/- 13 years, 45% male) were divided into two groups according to awake ABP: Group 1 (normal ABP < or = 136/86, n = 48), and Group 2 (abnormal ABP > 136/86, n = 79). Left ventricular mass index (LVMI) was greater (116 +/- 30 vs 101 +/- 25 g/m2, p < 0.01) and the proportion of patients with an increased LVMI was significantly higher (34% vs 17%, p = 0.05) in Group 2. During 1 year of follow-up, significantly more patients in Group 2 (34%) required antihypertensive treatment compared with Group 1 (8%, p = 0.01). ABP monitoring usefully discriminates between patients with true BHT and those with isolated clinic hypertension. An elevated awake ABP on initial assessment is associated with a higher LVMI and a greater likelihood of progression to moderate hypertension requiring pharmacological treatment.

Variability of diurnal changes in ambulatory blood pressure and nocturnal dipping status in untreated hypertensive and normotensive subjects

An absent or diminished blood pressure (BP) fall during sleep (so-called "nondipping") has been associated with a higher risk of cardiovascular complications, but the long-term reproducibility of dipper status and the relationship between diurnal changes in BP and perceived sleep quality have not been previously documented in untreated hypertensive patients. Ambulatory BP (ABP) and dipping status were examined in 79 subjects (69 hypertensives and 10 normotensives) at 0, 6, and 12 months. Fifty-six percent of subjects had no change in their dipping status, the majority (53%) dipping normally on all three occasions. However, 44% of patients had variable dipping status, and normal nighttime dipping in BP was observed more often when patients perceived their sleep quality to be good during the period of ABP recording. These results highlight significant intrasubject variability in the diurnal fluctuations in ABP and dipper status, which may in part reflect day-to-day variations in sleep disturbance during ABP monitoring. Classifying hypertensive patients into dippers or nondippers on the basis of a single ABP recording is unreliable and potentially misleading.

Clinical implications of white coat hypertension: an ambulatory blood pressure monitoring study

Within routine clinical practice, white coat hypertension (where blood pressure is persistently higher in the presence of the doctor or nurse but normal outside the medical setting) makes the diagnosis and management of hypertension difficult. There are conflicting data regarding the prevalence and significance of white coat hypertension. This study has used ambulatory blood pressure monitoring to detect the presence of white coat hypertension in 186 patients referred to an out-patient hypertension unit. The presence of white coat hypertension was defined as an average office blood pressure (measured on three occasions over a 2-month period) of >140/90 mm Hg and an ambulatory awake blood pressure < or = 136/86 mm Hg. The prevalence of white coat hypertension in those patients with borderline hypertension (diastolic blood pressure 90-99 mm Hg) and those with mild-to-moderate hypertension (diastolic blood pressure > or = 100 mm Hg) was determined. Echocardiography was used to assess left ventricular mass index in patients with and without white coat hypertension. The prevalence of white coat hypertension in the total group was 23%. However, the prevalence was higher (33%) in those patients with borderline hypertension compared to 9% of those patients with mild-to-moderate hypertension. There was a statistically significant increase in left ventricular mass index in patients with no evidence of white coat hypertension (125 gm/m2) compared to those with white coat hypertension (102 gm/m2). We conclude that, if office blood pressure is used to identify patients with hypertension who may require treatment, some patients will be incorrectly diagnosed and may be treated inappropriately. We recommend that ambulatory blood pressure monitoring is used in the routine assessment of all newly diagnosed hypertensive patients. Furthermore, we recommend echocardiography in patients with borderline hypertension as some will already have an increased left ventricular mass index.

Twenty-four hour ambulatory blood pressure: a sample from a normal British population

The aims of this study were to determine 24 h blood pressure (BP) levels in a sample taken from a normal British population, and to investigate factors contributing to variation within the sample. Two hundred and eighty-two Caucasian subjects, with no known hypertension or cardiovascular disease were recruited from local light industry and a general practice population. Office and 24 h BPs were measured. The mean office BP was 120/75, ambulatory mean awake 115/72 and mean asleep 97/58 mm Hg. Males had a small but significantly higher mean office and awake BP but there were no differences in asleep BP. Multiple step-wise regression with age, gender, weight and height showed age to be the best predictor of variation in office BP and awake and asleep diastolic BP. However, age accounted for only a small amount of the variation and did not contribute towards the variation in systolic BP. The two standard deviation upper limits for this population for awake, asleep and overall BP were 136/86, 121/73 and 131/82 mm Hg, respectively. In conclusion, these data providing information on 24 h BP in a healthy British population may be of value in the clinical interpretation of 24 h ambulatory BP recordings in patients with suspected hypertension.

Reduction in treatment delay by paramedic ECG diagnosis of myocardial infarction with direct CCU admission

OBJECTIVES

To establish the feasibility of training paramedics of diagnose acute myocardial infarction by ECG before hospital admission and whether direct paramedic coronary care admission, arranged by very high frequency (VHF) radio communication with the coronary care unit (CCU), would reduce delay of thrombolysis treatment.

DESIGN

Prospective controlled study.

SETTING

District general hospital CCU and a local district ambulance paramedic service.

PATIENTS

124 patients with ECG evidence of myocardial infarction or ischaemia admitted directly to the CCU by the paramedic service were compared with 123 patients admitted by the emergency department and subsequently transferred to the CCU.

MAIN OUTCOME MEASURES

ECG diagnostic accuracy by paramedics, and interval durations for CCU admission and thrombolysis.

RESULTS

ECG diagnostic accuracy by the paramedics was 87.5% in the training phase and 92% in admission. The total call to thrombolysis interval was reduced from 154 to 93 minutes and the "door to needle" interval was reduced from 97 to 37 minutes.

CONCLUSIONS

Trained paramedics can reliably diagnose myocardial infarction by ECG. The use of a direct admission procedure, by a VHF radio link to the CCU, substantially reduces the time interval for thrombolytic treatment after acute myocardial infarction.

Review: calcium antagonists and diuretics; a useful combination in the management of hypertension?

The use of the combination of a calcium antagonist with a thiazide diuretic for the treatment of hypertension has been the subject of much debate over a number of years. Early studies, with few subjects, demonstrated little benefit, but more recent research using larger numbers of subjects has shown quite clear additional antihypertensive effects of this combination. Combination therapy has an important role in the treatment of patients who do not respond to monotherapy, and the combination of a calcium antagonist and thiazide diuretic may be useful in the successful treatment of these patients.

Double-blind, parallel, comparative multicentre study of a new combination of diltiazem and hydrochlorothiazide with individual components in patients with mild or moderate hypertension

OBJECTIVE

To compare the antihypertensive efficacy and tolerability of a new combination preparation of diltiazem (150 mg) and hydrochlorothiazide (12.5 mg) with the individual constituents in patients with mild/moderate hypertension.

DESIGN

Multi-centre, double-blind, randomised parallel group study.

PATIENTS

Seventy-one patients with essential hypertension were recruited to the study.

TREATMENT

Following completion of the placebo run-in period 63 patients fulfilled the prerandomisation criteria and entered the 10 week treatment period. Patients were randomised to receive either the combination preparation (D 150 mg/H 12.5 mg), diltiazem (150 mg) or hydrochlorthiazide (12.5 mg). The dosage was increased in three patients who had not attained target blood pressure (BP) control after 6 weeks.

OUTCOME MEASURES

Response to treatment assessed by change from baseline in clinic and 24 h ambulatory BP.

RESULTS

The proportion of patients achieving target BP (a reduction in resting supine diastolic blood pressure (DBP) to below 90 mm Hg or a reduction of 10 mm Hg from baseline) was 80% in the combination group, 55% in the diltiazem group, and 38% in the hydrochlorothiazide group. The respective figures for reduction in supine DBP from baseline were 13.5 mm Hg, 11.2 mm Hg and 5.9 mm Hg. A similar treatment order appeared throughout each of the efficacy variables. BP control throughout the 24 h dosing interval was demonstrated by ambulatory BP monitoring. Each treatment was well tolerated.

CONCLUSION

This study provides clear evidence of the efficacy of combination therapy with diltiazem and hydrochlorothiazide in the management of patients with hypertension.

Raised ambulatory blood pressure in type 1 diabetes with incipient microalbuminuria

Whether raised blood pressure precedes, follows or develops in parallel with the onset of microalbuminuria, remains unclear. Previous studies, using conventional blood pressure recordings, have yielded discrepant results. Ambulatory blood pressure (ABP) monitoring detects borderline hypertension more reliably, and correlates more closely with end-organ damage. We have therefore compared ABP and left ventricular dimensions in normotensive insulin-dependent diabetic patients with or without microalbuminuria, and matched nondiabetic control subjects. Those diabetic patients with microalbuminuria, and to a lesser extent those without, had higher 24 h mean arterial blood pressure than matched non-diabetic control subjects, with corresponding increases of left ventricular mass, interventricular septal width and posterior wall thickness. These observations suggest that raised arterial blood pressure is present at an early stage of 'incipient' microalbuminuria.

How reliable is the electrocardiogram in detecting left ventricular hypertrophy in hypertension?

This paper assesses the sensitivity and specificity of the electrocardiogram in detecting left ventricular hypertrophy in 75 hypertensive patients. Each patient underwent a 12 lead electrocardiogram and echocardiogram. Left ventricular mass index, using echocardiogram, was calculated according to the Penn convention and left ventricular hypertrophy was assessed by standard electrocardiographic criteria. The electrocardiogram was found to be very specific but insensitive in the detection of left ventricular hypertrophy as compared with the echocardiogram. Other non-voltage dependent markers appeared to have similar reliability. We conclude that the electrocardiogram may be unreliable in the detection of left ventricular hypertrophy in hypertensive patients. Accurate assessment of left ventricular hypertrophy, in these patients should be by echocardiography.

Type III collagen mutations cause fragile cerebral arteries

Premature vascular aneurysms and fragility of cerebral arteries are commonly associated with type III collagen mutations and physical signs suggesting a generalized abnormality of connective tissue. Sometimes these traits are clearly genetically transmitted. Here we present seven examples of early cerebrovascular aneurysms or fragility including five examples of carotid cavernous sinus aneurysms. With one exception in which we suspect the mutation is too small to be detected, all of them had easily visible abnormalities of their type III collagen proteins. Further work in progress will eventually allow the characterization of their mutations at gene sequence level and will be followed by the ability to prevent transmission of the mutant genes in these families.

Prediction of "critical" coronary disease: are the "Consensus Conference" guidelines adequate?

Presenting features of 100 patients with significant left main coronary stenosis (LMCS) were reviewed. All presented with angina--on minimal exertion in 45, moderate exertion in 38, and severe exertion in 6--and 11 had unstable angina. Although the resting ECG was normal in 44, exercise testing was positive in 92% of patients tested. The authors conclude that symptoms and the resting ECG alone are unhelpful in predicting "critical" coronary disease. However, application of a management plan similar to that suggested by the Consensus Conference on coronary artery surgery would have selected the vast majority of such patients for angiography.

The safety of ambulatory intra-arterial pressure monitoring: a clinical audit of 1000 studies

Between 1973 and 1981 1000 successful studies involving ambulatory monitoring of intra-arterial blood pressure were performed using percutaneous cannulation of the brachial artery. We have reviewed the clinical effects of these studies and 35 other cases where attempted cannulation was unsuccessful. One major complication occurred, when an infected haematoma arising at the cannulation site led to the formation of a false aneurysm. In only one other case was distal pulsation diminished following the study. There were 157 reported "minor" complications in 122 studies, including haematoma, haemorrhage, transient paraesthesiae in median nerve territory, and evidence of micro-emboli. A limited study using pulsed wave Doppler ultrasound revealed no significant alteration in arterial lumen size or flow in 20 subjects. The procedure was therefore associated with a much smaller incidence of clinical problems than has been reported with other investigations involving cannulation of the brachial artery.

The effects of oxprenolol on ambulatory intra-arterial blood pressure in essential hypertension

Continuous intra-arterial blood pressure recording using the "Oxford" technique has been used to study the antihypertensive effects of oxprenolol taken three times daily in fully ambulatory patients with essential hypertension, outside hospital. During the first 24 h of treatment there was a reduction in daytime heart rate and a small reduction in daytime blood pressure. After 10 weeks treatment there was a more substantial fall in daytime blood pressure from the hour of waking, but no effect on sleeping nighttime blood pressure or heart rate. Twenty-four hour variation, as assessed by the amplitude of a fitted regression curve, showed a reduction in heart rate but not blood pressure variation. In 4 patients restudied after 11 weeks treatment with oxprenolol (tid) and cyclopenthiazide at 9 a.m. there was some evidence of an antihypertensive effect occurring during both the daytime and nighttime.

Circadian rhythms in hypertension

Continuous intra-arterial blood pressure recordings have been performed in 37 untreated ambulatory hypertensive subjects, who were investigated on an outpatient basis. Hourly data analysis demonstrated a circadian variation of both blood pressure and heart rate which were highest during the morning and fell during the late afternoon to reach a nadir during sleep. Prior to waking there was an increase in blood pressure, but not heart rate; however both blood pressure and heart rate increased briskly shortly after waking. Chronic therapy with oxprenolol (in 10 patients) reduced daytime blood pressure, but had little effect during the night-time or early morning.

Effects of chronic beta-blockade on intra-arterial blood pressure during motor car driving

Continuous intra-arterial blood pressure recordings during motor car driving were performed in 15 patients with untreated essential hypertension, using the "Oxford" recording technique. Each subject was an experienced driver who used his car every day, and for the study drove from his work place to the hospital during the later afternoon. This drive took place in urban traffic and the average duration was 20.9 minutes. Blood pressure during car driving was remarkably stable, and the average systolic and diastolic pressures were similar to the mean daytime pressure. After 16 weeks of treatment with oxprenolol each patient was restudied. Blood pressure during driving had dropped from 176/107 to 160/93 mmHg, but the blood pressure response to driving and blood pressure variation during driving (expressed as the coefficient of variation) were unchanged. After treatment, the mean daytime systolic pressure was lower than the mean pressure during driving, but the relative antihypertensive effect during driving was similar to that observed in the same patients during dynamic exercise on a bicycle ergometer. No drug-induced side effects occurred and there were no apparent effects on driving ability. Chronic treatment with oxprenolol reduced blood pressure during car driving without affecting the normal blood pressure response to driving.

Aortic regurgitation in seropositive juvenile arthritis

Seropositive juvenile chronic arthritis is a relatively uncommon form of childhood arthritis, but it often causes severe destruction of joints associated with considerable functional disability. During the last 7 years lone aortic regurgitation has been seen to develop in 4 such patients and pursue a particularly aggressive course. Sudden deterioration occurred in 2, 1 of whom required urgent aortic valve replacement and 1 died while awaiting assessment. Because of this it is important to include regular cardiac appraisal as part of the routine assessment in seropositive juvenile arthritis.

Effects of oxprenolol on the intra-arterial blood pressure response to dynamic exercise in hypertensive men

The intra-arterial blood pressure of 20 male patients with essential hypertension was continuously recorded during dynamic exercise. Graded exercise testing on a bicycle ergometer and a stair-climbing test were performed prior to and during treatment with oxprenolol. Acute oxprenolol therapy was associated with a reduction in heart rate but little reduction in blood pressure. Chronic treatment for 14.3 weeks with oxprenolol (mean daily dose, 344 mg) was associated with a substantial reduction of blood pressure at rest and at each level of bicycle exercise. A similar antihypertensive effect was demonstrated during stair climbing. The normal blood pressure response to exercise as assessed by the relative (percentage) increase in pressure above the pre-exercise level and the rate of increase in blood pressure (per unit of work), as well as exercise tolerance, were unchanged by chronic beta-blockade with oxprenolol.

Electrocardiographic changes following a cardiac stab wound. Case report and review of the literature

A patient is described who sustained a cardiac stab wound which was associated with ECG evidence of a full thickness myocardial infarction. Subsequent investigation showed a localized area of dyskinesia on left ventricular angiography, but normal thallium myocardial perfusion and normal anatomy on coronary angiography. The patient was managed conservatively and made a complete and uneventful recovery. It is concluded that extensive ECG changes following a cardiac stab wound need not be associated with major coronary artery damage.

Use of graded exercise testing in assessing the hypertensive patient

Twenty-five patients with suspected hypertension were studied using the "Oxford" continuous intra-arterial blood pressure recording technique. Each patient carried out graded exercise on a bicycle ergometer, using a standard protocol, and then underwent a fully ambulatory 24-h outpatient blood pressure recording. Using computer analysis, ambulatory blood pressure in each patient was characterised by measuring the mean daytime systolic and diastolic pressures. Exercise was found to be associated with a characteristic increase in systolic and diastolic blood pressure. Submaximal and maximal exercise blood pressures were shown to correlate strongly with ambulatory blood pressure. A much weaker correlation was found between clinic and ambulatory blood pressure. These findings suggest that the blood pressure response to exercise may be a better indicator of elevated blood pressure than a causal clinic blood pressure in individual borderline subjects.

A double-blind trial of disopyramide, procaineamide and digoxin in paroxysmal suptraventricular tachycardia

A double-blind cross-over study has been performed in 10 patients with an established diagnosis of paroxysmal suptraventricular tachycardia to compare the effectiveness of three active agents with placebo. The drugs were administered in random sequence for two-week periods with three-day washout intervals and in standard dose regimes as recommended for prophylaxis by authoritative works on the subject. The results suggest that digoxin is ineffective at the recommended dosage. Procaineamide was effective in controlling some arrhythmias, but disopyramide was the most effective agent studied. All these patients showed a mixture of arrhythmias, and also had a lot of ectopic activity. Arrhythmic activity is erratic and unpredictable, and a larger number of patients would need to be studied for long periods of time to obtain enough data for valid statistical assessment.

Effect of labetalol in hypertension during exercise and postural changes

1 Fourteen hypertensive patients were studied by intra-arterial BP monitoring to quantify the effects of standardized physiological stresses: Valsalva manoeuvre, isometric, treadmill and bicycle exercise, and 60 degree tilting before and after labetalol treatment. 2 The dose of labetalol ranged from 100--600 mg three times daily and the response was judged on outpatient clinic recordings. 3 The drug produced a sustained reduction of BP and heart rate responses during dynamic exercise and the Valsalva manoeuvre, but the degree of change from the lowered baseline were not changed by labetalol. The fall in BP on cessation of exercise was decreased rather than increased. 4 The response to controlled isometric muscle contraction was affected in a similar fashion. 5 Tilting produced a fall in BP after treatment, and this was most marked in those patients on the highest doses. However, compensatory increases in diastolic BP were observed.

Effect of labetalol on continuous ambulatory blood pressure

1 The hypotensive action of labetalol was evaluated during 24 h by continuous intra-arterial ambulatory monitoring in 14 patients. The dose used ranged from 300--1800 mg daily. 2 The drug caused a significant reduction of systolic BP in 19 and diastolic BP in 20 of the 24 h of monitoring. Heart rate was also reduced but less markedly than BP. 3 The rapid early morning increase in BP was also effectively controlled. 4 The mild pre-waking increase in BP was not significantly reduced. 5 Labetalol treatment reduced the variation in systolic BP from the lowest observed quarter-hourly mean as compared with pre-treatment values. 6 The quarter hourly mean values were consistently smooth and revealed no sudden variations which might have resulted from postural hypotension.

Circadian variation of blood-pressure

Continuous intra-arterial blood-pressure and electrocardiogram recordings were obtained in twenty hypertensive and five normotensive ambulant patients. Blood-pressure was highest mid-morning and then fell progressively throughout the remainder of the day. Blood-pressure was lowest at 3 A.M. and began to rise again during the early hours of the morning before waking. These findings may have important consequences with regard to the therapeutic management of hypertension.