Maximum Systolic Blood Pressure Research Articles

Exaggerated blood pressure response to maximal exercise in endurance-trained individuals.

Recent studies have suggested that an exaggerated blood pressure response to maximal exercise may be useful in detecting individuals who are prone to developing hypertension in later years. To examine the hypothesis that regular aerobic exercise results in a smaller blood pressure response to maximal exercise, 26 endurance-trained and 31 untrained individuals (matched on age and physical characteristics) performed graded maximal exercise tests on a cycle ergometer. Trained subjects achieved a significantly (P < .05) higher level of maximal oxygen uptake (mean +/- SE: 59.4 +/- 1.4 v 44.7 +/- 1.0 mL/kg/min), as well as a greater maximal work rate. Although there was no significant difference in resting blood pressure between the groups, endurance-trained individuals demonstrated significantly higher maximal systolic blood pressure levels compared to untrained subjects during maximal exercise (225 +/- 3 v 204 +/- 4 mm Hg). The group differences in systolic blood pressure were also significant (P < .05) at work rates of 180 W and higher. It is concluded that physically active individuals show higher blood pressure responses to maximal exercise, despite their reduced risk of future hypertension. This finding indicates that an exaggerated blood pressure response is not a valid prognostic test to indicate the likelihood of future hypertension in this population.

Predictors of outcome in Cryptococcus neoformans var. gattii meningitis.

In Papua New Guinea, Cryptococcus neoformans var. gattii meningitis has a high fatality rate even in immunocompetent patients. Our retrospective study attempted to identify marker of poor prognosis. Of 88 immunocompetent patients, 30 (34.1%) died, usually soon after admission, and mortality was higher in men (p = 0.025) and older patients (p = 0.039). Death was associated with altered consciousness (p < 0.001), a history of convulsions prior to treatment (p = 0.002) and a maximum systolic blood pressure of > 150 mmHg (p = 0.017). These data suggest that death results from raised intracranial pressure and subsequent tentorial herniation. However, CSF opening pressure measured on admission was raised in 29/36 (81%) patients and did not predict outcome. In survivors, relapse was uncommon and was not predicted by discharge serum cryptococcal antigen titres, which were frequently raised on completion of therapy in asymptomatic patients. Mortality may be reduced if efforts are made to lower intracranial pressure in those patients who present with markers of poor prognosis.

Maximal exercise hemodynamics and risk of mortality in apparently healthy men and women.

The purpose of this investigation was to determine the association of maximal exercise hemodynamic responses with risk of mortality due to all-causes, cardiovascular disease (CVD), and coronary heart disease (CHD) in a population of apparently healthy individuals. Study participants were 20,387 men (mean age = 42.2 yr) and 6,234 women (mean age = 41.9 yr), patients of a preventive medicine center in Dallas, TX, examined between 1971 and 1989. Maximal heart rate and maximal systolic blood pressure (SBP) measured during the maximal exercise test were related to risk of all-cause, CVD, and CHD mortality. During an average of 8.1 yr of follow-up, there were 348 deaths in men and 66 deaths in women. Among men, after adjustment for confounding variables, risks (and 95 percent confidence interval (CI)) of all-cause mortality for quartiles of maximal SBP, relative to the lowest quartile, were: 0.96 (0.70-1.33), 1.36 (1.01-1.85), and 1.37 (0.98-1.92) for quartiles 2-4, respectively. Similarly adjusted risks for maximal heart rate were: 0.61(0.44-0.85), 0.69 (0.51-0.93), and 0.60 (0.41-0.87). Similar results were seen for risk of CVD and CHD death. In women, similar trends in adjusted risks of all-cause and CVD mortality across maximal SBP and heart rate categories were observed. For maximal heart rate, a 35 bpm higher value was associated with a 36 percent decreased risk of CVD mortality in men (RR = 0.63,95 percent CI = 0.34-0.71) and an 8 percent lower risk in women (RR = 0.92,95 percent CI = 0.18-4.63). These results suggest that an exaggerated SBP or an attenuated heart rate response to maximal exercise may indicate an elevated risk for mortality in this apparently healthy population.

Blood Pressure Ranges in Premature Infants: II. The First Week of Life

To examine the arterial blood pressure in the first week of life in a healthy premature population. Population-based cohort study. Three intensive care nurseries in central New Jersey. Premature infants with birth weights less than 2000 g. We documented daily maximum and minimum systolic and maximum and minimun diastolic blood pressures during the first 7 days of life. To examine the effects on the ranges of blood pressure, we identified four groups of infants: (1) healthy infants without any of the major risk factors (n = 193); (2) infants who were mechanically ventilated but free of any of the other conditions (n = 225); (3) infants with histories of maternal hypertension or preeclampsia (n = 38) and (4) infants with low Apgar scores (less than 3 at 1 minute and less than 6 at 5 minutes) regardless of the presence of other conditions (n = 86). Blood pressure increased steadily in the first week of life in all four groups. There was no relationship between any of the four blood pressure variables, or trends in blood pressure over time, with birth weight, gender, or race. Regression equations (based on all infants with available data) for blood pressure ranges by day of life revealed that the maximum systolic blood pressure increased by 2.6 mm Hg/d, the minimum systolic blood pressure increased by 1.8 mm Hg/d,the maximum diastolic blood pressure increased by 2.0 mm HHg/d, and the minimum diastolic blood pressure increased by 1.3 Hg/d. Infants with birth asphyxia and ventilated infants had significantly lower systolic and diastolic blood pressures than healthy infants.

Immunohistochemical localization of extracellular matrix proteins in cerebral vessels in chronic hypertension.

Vascular hypertrophy or vascular remodeling are both associated with an increase in the extracellular matrix of cerebral arteries and arterioles in chronic hypertension. Rats with chronic renal hypertension were studied to determine whether the extracellular matrix proteins--collagen IV, laminin, and fibronectin--are increased in the thick-walled cerebral vessels in brain and those associated with areas of blood-brain barrier (BBB) breakdown to protein. The latter was detected by extravasation of endogenous serum proteins in brain. Serum proteins and the extracellular matrix proteins--fibronectin, laminin, and collagen IV--were detected by immunohistochemistry. Hypertensive rats having blood pressures over 150 mm Hg showed mild to moderate degrees of mural thickening of pial and intracerebral arterioles. In addition, these vessels demonstrated increased immunoreactivity with collagen IV, fibronectin, and laminin antisera. This occurred concomitant with the development of hypertension and prior to the observation of BBB breakdown to protein. Four rats having mean maximum systolic blood pressures in excess of 220 mm Hg developed multifocal areas of increased vascular permeability to endogenous serum proteins in the boundary zones of the territories supplied by the major cerebral arteries. The arterioles in these areas showed a severe degree of vascular thickening, which was due to medial hyperplasia/hypertrophy and increased mural deposition of serum proteins and the extracellular matrix proteins--laminin, fibronectin, and collagen IV. This study demonstrates that extracellular matrix proteins play an important role in the vascular response to increased intraluminal pressure. However, since this change occurs in diseases in the absence of hypertension it should be regarded as a nonspecific response of cellular components of vessel walls to injury.

Clinical Implications of White Coat Hypertension

To determine the clinical implications of mild white coat hypertension (WCH). We studied 102 subjects (54 men, 48 women), 51 of whom were normotensive and 51 slightly hypertensive. None had ever received antihypertensive therapy. An ambulatory blood pressure (ABP) record (Accutracker II), a 24-h electrocardiogram and an echocardiogram were obtained from each, and each was examined by funduscopy. WCH subjects were compared with sustained hypertension (SH) subjects and with normotensives. Fifty-three percent of the hypertensives qualified as WCH. The ultrasonographic characteristics and the ABP variables of the WCH group differed significantly from those of normotensives, but not from those of the SH group. The prevalence of left ventricilar hypertrophy (LVH) in the SH group (62.5%) did not differ significantly from its prevalence in the WCH group (40.7%), but the prevalence among normotensives (17.6%) was significantly lower than in either of the other two groups. The WCH and SH groups did not differ significantly as regards the prevalence of hypertensive retinopathy (33.3% in the former, 58.3% in the latter). For no non-LVH, non-retinopathic subject, whether normotensive or hypertensive, were more than 18% of daytime diastolic ABP measurements > or = 90 mmHg. Ultrasonographic findings were no better correlated with ABP than with in-clinic BP measurements. Fundus findings correlated well with in-clinic BP and with numerous ABP parameters. Retinopathy, with or without LVH, was efficiently predictable among hypertensives on the basis of body mass index and the 24-h maximum of systolic BP. Myocardiac remodelling and vascular retinopathy develop early and in parallel in hypertensives, and both developments appear to involve determinants including body mass index and 24-h maximum systolic BP. WCH subjects, as defined by current ABP-based criteria, have cardiac and retinovascular characteristics different to normotensive subjects. Stricter criteria are needed to discriminate between hypertensives with and without the systemic developments that constitute the immediate source of risk to the hypertensives individual.

Safety and efficacy of computerized closed-loop delivery of arbutamine: A new pharmacologic myocardial stress modality for the assessment of coronary artery disease

This study evaluated the efficacy of computer-controlled closed-loop delivery of a new synthetic catecholamine, arbutamine, when given to induce myocardial ischemia detected by electrocardiography and echocardiography with a high (10 beats/min/min) and low (6 beats/min/min) rate of increase in heart rate (heart rate slope) in 70 patients with coronary artery disease. The electrocardiographic sensitivity for the detection of myocardial ischemia was 52% for the low slope and 51% for the high slope. The corresponding figures for echocardiographic sensitivity were 83% and 79% for the low and high slopes, respectively. There were no significant differences in changes from baseline to maximum in pharmacodynamic variables, although the mean times to reach maximum heart rate and systolic blood pressure were 1.4 minutes shorter (p = 0.001) and 3.7 minutes shorter (p < 0.05), respectively, for the high-slope regimen. The duration of the infusion was shorter (p < 0.001) for the high slope. In this study, closed-loop arbutamine administration was effective and safe in the detection of coronary artery disease for both heart rate slope regimens.

Metoprolol treatment for two years after coronary bypass grafting: effects on exercise capacity and signs of myocardial ischaemia.

To evaluate whether prophylactic treatment with metoprolol for two years after coronary artery bypass grafting improves working capacity and reduces the occurrence of myocardial ischaemia in patients with coronary artery disease. After coronary artery bypass grafting, patients were randomised to treatment with metoprolol or placebo for two years. Two years after randomisation, a computerised 12-lead electrocardiogram was obtained during a standardised bicycle exercise test in 618 patients (64% of all those randomised). The median exercise capacity was 140 W in the metoprolol group (n = 307) and 130 W in the placebo group (n = 311) (P > 0.20). An ST depression of > or = 1 mm at maximum exercise was present in 34% of the patients in the metoprolol group and 38% in the placebo group (P > 0.20) and an ST depression of > or = 2 mm at maximum exercise was present in 11% in the metoprolol group and 16% in the placebo group (P = 0.09). The median values for maximum systolic blood pressure were 200 mm Hg in the metoprolol group and 210 mm Hg in the placebo group (P < 0.0001), while the median values for maximum heart rate were 126 beats/min in the metoprolol group and 143 beats/min in the placebo group (P < 0.0001). The occurrence of cardiac and neurological clinical events two years postoperatively among exercised patients was comparable in the treatment groups. Treatment with metoprolol for two years after coronary artery bypass grafting did not significantly change exercise capacity or electrocardiographic signs of myocardial ischaemia.

Characteristics of patients surviving more than ten years after cardiac transplantation

The clinical status and quality of life of 40 patients who lived or are still alive more than 10 years after transplantation at our institution were reviewed with the use of our transplant database, prospective patient examinations, cardiac catheterization, and exercise testing. Patient-perceived health status was determined with use of the Nottingham Health Profile and General Well Being examinations. Factors associated with longevity were determined by a Cox proportional hazards model. Twenty-six patients are alive and 14 have died. The mean age at transplant was 32.4 ± 12 years and the current age (or age at death) is 46.1 ± 12.8 years. Actuarial freedom from rejection was similar to that of patients surviving less than 10 years ( p = 0.8), but freedom from all types of infection was less ( p = 0.005). I mmunosuppressive drugs include cyclosporine (11/26 patients), azathioprine (24/26), and prednisone (26/26, mean dose 12.7 mg/day). Catheterization hemodynamic data show well-preserved graft function at a mean follow-up of 11.7 ± 3.3 years. Graft coronary artery disease prevalence is 51.0% ± 8%. Exercise test results are as follows: duration 8.7 ± 3.5 minutes (range 2 to 16 minutes), maximum heart rate/expected rate 77.3% ± 11% (50% to 92%), maximum systolic blood pressure 171 ± 23 mm Hg (140 to 208 mm Hg), and metabolic equivalents 9.2 ± 2.3 units (5.5 to 12.9 units), or about 84% of predicted. Mean score on the General Well Being examination was 75.3 ± 21.6 (normal). Nottingham Health Profile scores were nearly normal, except for in the 50- to 64-year-old age group in categories of mobility, pain, sleep quality, and energy level. Causes of death were coronary artery disease in 7 of 14, infection in 4 of 14, lymphoma in 1 of 14, and nonlymphoid cancer in 2 of 14. In the Cox regression, variables most associated with survival t > 2.0, multivariate p = 0.0005) were age at transplantation ( t = 3.26), preoperative duration of illness ( t = 3.57), postoperative cytomegalovirus infection ( t = 2.16), and ejection fraction at 12 months after operation ( t = -2.62). We conclude that cardiac transplantation can provide patients with end-stage cardiac failure an acceptable general medical condition, functional status, and perceived quality of life well into the second decade after operation. (J T HORAC C ARDIOVASC S URG 1995;109:1103-15)

958-96 Enalapril Does not Affect Ischemia During Short-term Treatment in Stable Angina Pectoris Irrespective of Its Effect on Blood Pressure

Whereas ACE inhibition acutely reduces myocardial ischemia (MI) through neuroendocrine modulation and, after long-term treatment (1 year), affects ischemic events in LV dysfunction. the short-term antiischemic properties in chronic, stable anginal patients and normal LV function are debated. As a pro-ischemic effect may be explained by lowering coronary artery perfusion pressure, the effects of enalapril (E) 10 mg b.i.d. on ischemia in relation to blood pressure (BP), and placebo b.i.d. were compared in 27 patients with chronic exercise-induced angina pectoris in a double-blind cross-over trial with 2 treatment periods of 2 weeks each. Exercise performance was assessed using treadmill exercise tests. No period or treatment sequence effects were observed for BP, heart rate and exercise performance. After treatment with E, resting systolic and diastolic BP were 7% and 6%, respectively, lower compared to placebo. During maximal exercise, systolic BP and ratepressure product (RPP) were similar during both treatments, whereas diastolic BP was 6% less with E. Maximal workload was comparable after both treatment periods. No differences between treatment were seen with regard to exercise duration, time to angina, maximal ST-depression (0.2 mV in both groups) and time to 0.1 mV ST-depression. When patients were divided into 2 groups according to BP response on an initial dose of 10 mg E, 11 pts ≥ 20 mmHg and 16 pts &lt; 16 mmHg, still no differences during exercise were found. Thus, in stable chronic exercise-induced angina, short-term E does not decrease myocardial ischemia, irrespective of first-dose BP response. Also, no pro-ischemic effects as a result of lowering coronary artery perfusion pressure were observed.

1010-120 Comparison of Arbutamine Stress and Treadmill Exercise Thallium-201 SPECT: Hemodynamics and Diagnostic Accuracy

Arbutamine (ARB). a new β -agonist developed as a pharmacologic stress agent, was compared with treadmill exercise testing (Ex) in a multicenter study using thallium-201 (TI) SPECT A total of 75 patients (pts) performed both forms of stress. Of the 73 pts having quantitative angiography, 68 (93%) had coronary artery disease ( ≥ 50% stenosis). TI scans were obtained in 68 pts and were scored by a central laboratory using a twenty segment (seg)/scan visual analysis (5 point system: 0 = normal, 4 = absent uptake; segmental score ≥2 = defect). Stress TI segs with defects were further classified as reversible (rev) or nonreversible (nonrev). Hemodynamic response was summarized for 75 pts. Maximum heart rate (HR) by ARB and Ex was 122 vs 141 bpm, respectively (p &lt; 0.05); mean %HR change from baseline was similar (79% vs 82%, respectively). Maximum systolic BP for ARB and Ex was 173 vs 176 mmHg, respectively and mean %change from baseline was 31% vs 26%, respectively (p = NS for both). In the 68 pts with angiographic CAD, sensitivity for detecting CAD by ARB TI was 94% and 97% by Ex TI-SPECT (p = NS). Stress TI-SPECT segmental agreement for presence or absence of defect between ARB and Ex in 1360 segs (68 pts) was 94% (k = 0.7). Of 76 discordant segs, 38 (50%) were normal by ARB and abnormal by Ex. Exact segmental stress TI score (0–4) agreement was 85% (k = 0.7). Of the 199 segs with discordant scores, the ARB-TI score was higher in 98 (49%), Among 346 segs with stress defects by both ARB and Ex, defect rev agreement was 86% (k = 0.7). Of the 50 discordant segs, 25 (50%) were rev by ARB and nonrev by Ex. Adverse events were mostly mild. Sustained arrhythmias were not observed; 3 pts had nonsustained ventricular tachycardia with ARB and 1 with Ex. In this patient population, arbutamine and treadmill exercise produced a similar degree of hemodynamic response compared to baseline. The two forms of stress yielded similar diagnostic accuracy and high agreement for the presence, extent, severity and reversibility of stress myocardial perfusion abnormalities.

Effects of bisoprolol on left ventricular hypertrophy in essential hypertension

Previous studies have shown that beta-adrenergic blocking drugs can reverse ventricular hypertrophy in patients with systemic hypertension. Thirty patients with essential hypertension and left ventricular hypertrophy were studied at baseline after withdrawing all previous treatments and after 6 months of treatment with 5-20 mg of bisoprolol, a new beta-selective agent, to assess its possible action on left ventricular mass. Three patients did not finish the study. Blood pressure was reduced to below 160/90 mmHg in 22 of the remaining 27 patients. At the end of follow-up, the left ventricular mass (echocardiography) was reduced from 308.1 +/- 89 g to 262.3 +/- 51 g (p < 0.001) and left ventricular mass index from 165 +/- 47.4 g/m2 to 141.03 +/- 26.7 g/m2 (p < 0.001). The ratio of E wave/A wave velocity of transmitral blood flow measured by Doppler increased from 0.86 +/- 0.44 to 1.07 +/- 0.45 (p = 0.005). Peak filling rate, derived from nuclear ventriculography, changed from 2.05 +/- 0.4 EDV/sec before the treatment to 2.23 +/- 0.47 EDV/sec after it (p = 0.0046). Serum lipids as well as other biochemical tests were unchanged. Left ventricular volumes and ejection fraction did not change, and treadmill exercise time increased from 343 +/- 125 seconds to 420 +/- 135 seconds (p = 0.002). Maximal systolic blood pressure during exercise decreased from 197.2 +/- 19.7 mmHg to 182.9 +/- 25.8 mmHg (p = 0.011). There were few side effects. We conclude that bisoprolol reduces left ventricular mass, preserves systolic function, and improves diastolic function of the left ventricle in hypertensive subjects with left ventricular hypertrophy.

Hyperglycemia as a major determinant of distal polyneuropathy independent of age and diabetes duration in patients with recently diagnosed diabetes

In an attempt to identify the potential risk factors for diabetic neuropathy in patients recently diagnosed as diabetics, 742 non-insulin-dependent diabetics under 70 years of age who had been diagnosed as diabetics less than 5 years before the initial visit were examined in a cross-sectional study conducted at a university hospital. Neuropathy was defined as the presence of symptoms consistent with distal polyneuropathy, or the absence of tendon reflexes. Of the patients, 21% displayed neuropathy in this study, with no differences between the genders. Age was higher, duration of diabetes was longer, body mass index was lower, and fasting plasma glucose level was higher in patients with neuropathy than in those without neuropathy, for both genders. Body height, maximal body mass index, ethanol use, smoking status, systolic and diastolic blood pressure and serum cholesterol level did not differ between the two groups. Logistic regression analysis showed that fasting plasma glucose level ( χ 2 = 28.2) was a major determinant for neuropathy independent of diabetes duration (9.5), age (6.2) and maximal body mass index (3.9). Tight glycemic control from the onset of diabetes was concluded to be essential for the prevention of diabetic distal polyneuropathy.

Red cell sodium-lithium countertransport and blood pressure in children with insulin-dependent diabetes mellitus

Sodium-lithium countertransport and blood pressure responses, maximal elevated plasma norepinephrine concentrations induced by acute physical work load and the carbohydrate metabolic state were analyzed in 40 children suffering from insulin-dependent diabetes mellitus (IDDM). Patients were selected according to the duration of the disease to get a horizontal insight into the progression of the diabetes. Sixteen healthy children served as controls. Sodium-lithium countertransport (NaLi CT) was 281 ± 64 μmol/l red blood cells (RBC) per hour in the control group. NaLi CT was elevated in all diabetic groups (newly diagnosed: 455 ± 48; diabetics for 5–7 years: 495 ± 48; diabetics for 10–13 years: 470 ± 36). Plasma norepinephrine concentration increased during physical exercise, the elevation was more pronounced in diabetic children being 13.5 ± 10.4, 10.1 ± 5.0 and 12.3 ± 5.4 nmol/l in the three diabetic groups, respectively, which differed significantly from that of controls (7.94 ± 2.9; P < 0.01). Systolic blood pressure increased significantly during physical exercise in each group. However, maximal elevated systolic blood pressure was higher in children who had diabetes for more than 10 years than in controls (158 ± 11 vs. 137 ± 9.7 mmHg; P < 0.001). NaLi CT correlated positively with the maximal systolic blood pressure measured during physical exercise in those diabetic children who suffered from diabetes for more than 5 years. High activity of NaLi CT in combination with elevated blood pressure and high plasma concentration of norepinephrine induced by acute physical exercise may represent a risk of renal/vascular complications in patients suffering from IDDM.

Exercise blood pressure predicts cardiovascular mortality in middle-aged men.

The outcome of 1999 apparently healthy men aged 40 to 59 years investigated from 1972 through 1975 was ascertained after 16 years to determine whether systolic blood pressure measured with subjects in the sitting position during a bicycle ergometer exercise test adds prognostic information on cardiovascular mortality beyond that of casual blood pressure measured after 5 minutes of supine rest. During a total follow-up of 31,984 patient years, 278 patients died, 150 from cardiovascular causes. Casual blood pressure and pulse pressure as well as peak exercise systolic blood pressure during 6 minutes on the starting workload of 600 kpm/min (approximately 100 W, 5880 J/min) were all related to cardiovascular mortality. The relative risk (RR) of dying from cardiovascular causes associated with an increment of 48.5 mmHg (= 2 SD) in systolic blood pressure at 600 kilopondmeter (kpm)/min was significant (RR = 1.5, 95% confidence interval [CI] = 1.1-2.3, P = .040) even when adjusting for a large number of variables measured in the present study, including age, exercise capacity, smoking habits, and casual blood pressures. The influence of blood pressure at 600 kpm/min was so strong that the predictive value of resting casual blood pressures became nonsignificant when these were analyzed as continuous variables also including exercise blood pressure as a covariate. However, the maximal systolic blood pressure during the exercise test was unrelated to cardiovascular mortality.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of nifedipine on cystometry-induced elevation of blood pressure in patients with a reflex urinary bladder after a high level spinal cord injury

In 10 patients with a reflex urinary bladder after a cervical or high thoracic spinal cord injury, the effect of nifedipine on the cystometry-induced elevation of blood pressure was studied. The blood pressure was measured every 30 s in four consecutive cystometries before and after administration of 10 mg nifedipine sublingually. In each patient there was a decrease in the maximum systolic and diastolic blood pressure after the administration of nifedipine. In the whole group the mean maximum systolic pressure decreased significantly from 147 mmHg (range 119-165, SD 14) to 118 mmHg (range 99-145, SD 14). The mean maximum diastolic pressure decreased from 110 mmHg (range 96-124, SD 10) to 83 mmHg (range 71-99, SD 10). The effect of nifedipine was significant in each of the four cystometries that were performed. The decrease in blood pressure was due to both a significant decrease of the baseline pressure and a significant decrease of the blood pressure reaction during cystometry. Nifedipine may be useful in order to prevent dangerous blood pressure reactions, e.g. during cystoscopy and other diagnostic or therapeutic procedures in spinal cord injured patients with autonomic dysreflexia.

Efficacy and safety of ventricular rate responsive pacing in children with complete atrioventricular block.

Single chamber rate responsive pacing offers many potential advantages over the more complex dual chamber atrial tracking pacing mode in children, and the preservation of atrioventricular synchrony could be unnecessary in selected groups of pediatric patients. Twenty-two pediatric patients (age range 9 months to 12 years; mean 6.5 years) had implantation of ventricular rate responsive (VVIR) pacemakers over a 2-year period. All patients had chronic third-degree atrioventricular block, and a normal ventricular function at rest. During the follow-up each patient underwent a 24-hour Holter monitoring, and ten performed a graded treadmill test in both ventricular fixed rate (VVI) and rate responsive (VVIR) pacing mode. Paced ventricular rates were found to be normal for age in all 22 patients; maximum rate did not reach the higher programmed rate during daily activities in any patient. Comparing the mean paced ventricular rate to the mean rates of blocked P waves, six patients showed a difference of more than 20 beats/min, which induced the pacemaker parameters to be reprogrammed. In all patients a significant correlation was found between variations of paced ventricular rate and variations of spontaneous blocked atrial rhythm (P < 0.05); this correlation persisted in the subsequent Holter controls in the ten patients with longer follow-up. Exercise tolerance resulted normal in the ten patients who performed a treadmill test either in VVIR or VVI mode, with increased maximal heart rates and maximal systolic blood pressure in VVIR mode (P < 0.0013). Rate responsive ventricular pacemakers seem to adequately respond to the physiological needs of daily life of this selected group of children requiring permanent pacing.

Psychophysiological effects of cardiac rehabilitation in post-myocardial infarction patients

Psychophysiological reactivity and cardiovascular functioning were assessed in 40 patients with coronary heart disease before and after taking part in either a Type A modification training program or a control condition. Treated patients showed an overall attenuated heart rate (HR) response and prolonged diastolic time to mental stress performance, during recovery and rest periods, as compared lo control patients. No other measure, including impedance-cardiography-derived measures, differentiated the two groups. The treatment group showed reduction from before lo after treatment in 24-hr minimum IIR level and decreased frequencies of premature ventricular contractions, whereas the control group showed an opposite trend. Results from an exercise test suggested the same direction for resting IIR and double-product levels. The two groups did not differ in maximal systolic and diastolic blood pressure or in maximal double-product levels, despite a differential development, in favor of the treatment group, in maximal work capacity.

Does diurnal variation in blood pressure exist in CAPD patients?

The existence of diurnal variation in CAPD remains controversial. We therefore attempted to delineate the blood-pressure (BP) pattern in CAPD patients by ambulatory blood-pressure monitoring (ABPM). Initially ABPM was performed in 31 patients (21 M, 10 F), mean age 65.4 years (26-87) using the Spacelabs model 90207. The maximal normal BP preset on the recorder was 140/90 mmHg. Daytime and night-time readings, recorded every 30 min, were defined as those from 0600 to 2100 and 2100 to 0600 hours respectively. Mean duration of dialysis was 15.2 months (3-76). There were 14 hypertensive patients, defined as a basal BP > 140/90 mmHg, or those on antihypertensive medications. Taking the group as a whole a significant difference between day and night-time readings was found as regards minimal systolic BP (118 versus 107.6 mmHg), maximal systolic BP (181.6 versus 171.2 mmHg), mean diastolic BP (83.9 versus 79.6 mmHg), and maximal diastolic BP (121.7 versus 104.5 mmHg), P < 0.05. Diurnal variation, defined in the initial study as a 10% decrease of MAP occurring during any consecutive 4-h period, was present in 21 patients. In three the diurnal variation manifested as a paradoxical reduction of BP during the day. The only significant difference between those with diurnal variation and those without was the duration of dialysis, being 19.2 +/- 19.9 versus 13.3 +/- 17.3 months respectively, (P < 0.05). In a second study 18 hypertensive CAPD patients were subjected to ABPM. Nine of them had participated in the first study. These patients were specifically asked to detail their periods of sleep and arousal.(ABSTRACT TRUNCATED AT 250 WORDS)

The diagnosis and treatment of baroreflex failure.

Baroreflexes originate in the great vessels of the neck and thorax and prevent arterial pressure from rising or falling excessively. This study was undertaken to clarify the cause, clinical spectrum, and therapy of this disorder. We studied 11 patients with baroreflex failure presenting as severe, labile hypertension and hypotension, often with headache, diaphoresis, and emotional instability, and characterized by the failure of exogenous vasoactive substances to alter heart rate. Each underwent hemodynamic monitoring and biochemical, physiologic, and pharmacologic testing. The patients' maximal systolic blood pressures ranged from 164 to 280 mm Hg, and their minimal systolic pressures ranged from 58 to 96 mm Hg. Plasma norepinephrine and epinephrine concentrations were sometimes many times normal during blood-pressure surges. All the patients had excessive pressor and tachycardia responses to the mental-arithmetic and cold pressor tests and marked hypersensitivity to clonidine. The underlying causes of baroreflex failure included the familial paraganglioma syndrome, neck surgery or radiation therapy for pharyngeal carcinoma, bilateral lesions of the nucleus tractus solitarii, and surgical section of the glossopharyngeal nerves; in two patients the cause was unknown. Therapy with clonidine reduced the frequency of attacks by 81 percent and attenuated the elevated blood pressure and heart rate in the attacks that occurred. The syndrome of baroreflex failure should be considered in patients with otherwise unexplained labile hypertension. Clonidine attenuates the pressor and tachycardic surges in baroreflex failure.