The prognostic value of haemodynamic parameters in the recovery phase of an exercise test. The Finnish Cardiovascular Study

We tested the hypothesis that the change from the peak to recovery values of systolic arterial pressure (SAP recovery) and rate-pressure product (RPP recovery) can be used to predict all-cause and cardiovascular mortality, as well as sudden cardiac death (SCD) in patients referred to a clinical exercise stress test. As a part of the Finnish Cardiovascular Study (FINCAVAS), consecutive patients (n=2029; mean age+/-SD=57+/-13 years; 1290 men and 739 women) with a clinically indicated exercise test using a bicycle ergometer were included in the present study. Capacities of attenuated SAP recovery, RPP recovery and heart rate recovery (HRR) to stratify the risk of death were estimated. During a follow-up (mean+/-s.d.) of 47+/-13 months, 122 patients died; 58 of the deaths were cardiovascular and 33 were SCD. In Cox regression analysis after adjustment for the peak level of the variable under assessment, age, sex, use of beta-blockers, previous myocardial infarction and other common coronary risk factors, the hazard ratio of the continuous variable RPP recovery (in units 1000 mm Hg x b.p.m.) was 0.85 (95% CI: 0.73-0.98) for SCD, 0.87 (0.78-0.97) for cardiovascular mortality, and 0.87 (0.81 to 0.94) for all-cause mortality. SAP recovery was not a predictor of mortality. The relative risks of having HRR below 18 b.p.m., a widely used cutoff point, were as follows: for SCD 1.28 (0.59-2.81, ns), for cardiovascular mortality 2.39 (1.34-4.26) and for all-cause mortality 2.40 (1.61-3.58). In conclusion, as a readily available parameter, RPP recovery is a promising candidate for a prognostic marker.

Potassium channel KCNH2 K897T polymorphism and cardiac repolarization during exercise test: The Finnish Cardiovascular Study

OBJECTIVE

Cardiac repolarization is regulated, in part, by the KCNH2 gene, which encodes a rapidly activating component of the delayed rectifier potassium channel. The gene expresses a functional single nucleotide polymorphism, K897T, which changes the biophysical properties of the channel. The objective of this study was to evaluate whether this polymorphism influences two indices of repolarization--the QT interval and T-wave alternans (TWA)--during different phases of a physical exercise test.

MATERIAL AND METHODS

The cohort consisted of 1,975 patients undergoing an exercise test during which on-line electrocardiographic data were registered. Information on coronary risk factors and medication was recorded. The 2690A>C nucleotide variation in the KCNH2 gene corresponding to the K897T amino acid change was analysed after polymerase chain reaction with allele-specific TaqMan probes.

RESULTS

Among all subjects, the QTc intervals did not differ between the three genotype groups (p> or =0.31, RANOVA). Women with the CC genotype tended to have longer QT intervals during the exercise test, but the difference was statistically significant only at rest (p = 0.011, ANOVA). This difference was also detected when the analysis was adjusted for several factors influencing the QT interval. No statistically significant effects of the K897T polymorphism on TWA were observed among all subjects (p = 0.16, RANOVA), nor in men and women separately.

CONCLUSIONS

The K897T polymorphism of the KCNH2 gene may not be a major genetic determinant for the TWA, but the influence of the CC genotype on QT interval deserves further research among women.

Pulse wave velocity reference values in healthy adults aged 26?75�years

The stiffening of arteries is associated with various cardiovascular diseases. Arterial stiffening can be studied utilizing arterial pulse wave velocity (PWV), but the absence of reliable reference values for PWV has limited its use in clinical practice. The aim of this study was to establish a range of reference values for PWV. PWV was examined by measuring the time difference of systolic pulse waves in arteries from the aortic arch to the popliteal artery using whole-body impedance cardiography (ICG). The study population consisted of 799 individuals (age range 25-76 years), 283 of whom had no evidence of cardiovascular disease, and a low burden of risk factors was selected to represent an apparently healthy population. In healthy study population, PWV was higher in males (8 x 9 +/- 1 x 8 m s(-1)) than females (8 x 1 +/- 2 x 0 m s(-1), P<0 x 001). Young males had lower PWV values than old males. Correspondingly, young females also had lower PWV values than old females. PWV was clearly associated with age, and PWV was higher in young and middle-aged males than in females. There was no statistically significant difference between old males and females in PWV. In conclusion, whole-body ICG provides a practical method for PWV measurement. Reference values can be useful in the clinical management of patients, especially in detecting early vascular disease or an increased risk of cardiovascular complications.

Diurnal and weekly rhythms of health-related variables in home recordings for two months

Several telecare systems for long-term monitoring of the well-being of patients at home have been developed as an aid in healthcare and to reduce hospitalization costs. Most of the systems have been designed to measure only one or two variables. Because well-being is a combination of both psychological and physiological wellness, there is a need to monitor several psychophysiological variables simultaneously in out-of-hospital conditions for a long period. To understand better the variability of patients' wellness-related variables in long-term recordings, the knowledge of the normal variation in health-related variables in healthy people is necessary. In our study, 14 healthy working middle-aged men were studied daily for 24 h and periods of 50 to 79 days. The variables measured were beat-to-beat heart rate, motor activity, blood pressure, body weight, and temperature. At night respiratory frequency, time of movements, amount of quiet sleep, and ballistocardiographic respiratory variation were also measured. Heart rate variability in the waking period was calculated later (standard deviation of the 5 min average of the successive normal to normal beat to beat intervals). Daily self-reported well-being, activities, and consumption of alcohol were monitored by keeping a behavioral diary. After normalizing the physiological data, the diurnal and weekly variability was calculated for each variable. In several variables the most notable diurnal and weekly variability was found between working time and free time. In conclusion, diurnal and weekly rhythms in several wellness-related physiological and psychological variables were identified, depending on working and free-time in healthy middle-aged men.

Increased alveolar nitric oxide concentration in asthmatic patients with nocturnal symptoms

Nocturnal asthma symptoms and impaired lung function at night are related to inflammatory activity in the peripheral lung compartment. Exhaled nitric oxide (NO) measurement at multiple exhalation flow rates can be used to separately assess alveolar and bronchial NO production and inflammation. The authors hypothesised that asthmatic patients with nocturnal symptoms have a higher alveolar NO concentration than those with only daytime symptoms. The authors asked 40 patients with newly-diagnosed steroid-naïve asthma about their nocturnal asthma symptoms through the use of a written questionnaire. Alveolar NO concentration and bronchial NO flux were assessed in the 40 asthmatics and 40 healthy controls. Nineteen of the 40 patients reported nocturnal symptoms. Patients with nocturnal symptoms had a higher alveolar NO concentration (1.7+/-0.3 (mean+/-SEM) parts per billion (ppb)) than patients without nocturnal symptoms (0.8+/-0.3 ppb, p=0.012) or healthy controls (1.0+/-0.1 ppb, p=0.032). Bronchial NO flux was higher both in patients with (2.4+/-0.4 nL x s(-1), p<0.001) and without (2.6+/-0.4 nL x s(-1), p<0.001) nocturnal symptoms, compared to controls (0.7+/-0.1 nL x s(-1)). Nocturnal symptoms in asthmatic patients are related to a higher alveolar nitric oxide concentration. The results suggest that assessment of alveolar nitric oxide concentration can be used to detect the parenchymal inflammation in asthmatic patients with nocturnal symptoms.

Cardiovascular effects of ophthalmic 0.5% timolol aqueous solution and 0.1% timolol hydrogel

The objective of this randomized, double-masked, cross-over study was to compare the cardiovascular effects of two glaucoma formulations, ophthalmic 0.5% timolol aqueous solution and 0.1% timolol hydrogel. Twenty-four young healthy subjects received for 2 weeks either twice daily 0.5% timolol solution or once daily 0.1% timolol hydrogel. Heart rate (HR), blood pressure, atrio-ventricular conduction (PR interval), corrected QT time (QTc) and heart rate variability (HRV) were measured in supine position and during head-up tilted position. The mean peak concentrations of timolol in plasma were significantly higher after administration of 0.5% aqueous solution than after 0.1% hydrogel. A 0.5% timolol aqueous solution decreased HR on average by 3 bpm in supine position and by 7 bpm in head-up tilted position while no significant effects were observed with 0.1% timolol hydrogel. During tilt test HR was significantly lower after administration of timolol aqueous solution than after timolol hydrogel (mean +/- SD, 77 +/- 11 bpm versus 86 +/- 13 bpm, P < 0.05). Timolol aqueous solution slightly decreased QTc during tilt (5.9 +/- 5.6 ms, P < 0.01). During tilt tests, timolol aqueous solution slightly increased atrio-ventricular conduction (7.2 ms, P = 0.02). No significant differences were found in HRV. These results indicate that in healthy volunteers, ophthalmic 0.5% timolol aqueous solution produces more pronounced cardiac beta-blocking effects than 0.1% timolol hydrogel.

Pulse pressure in tests improves the prediction of left ventricular mass: 10 years of follow-up

Literature does not agree with the usefulness of exercise blood pressure (BP) in predicting hypertension or target organ damage. In this prospective 10 years of follow-up, we evaluated if exaggerated BP responses to tests may improve the prediction of left ventricular mass index (LVMI). At baseline, BP was recorded by casual measurements, and during tests using intra-arterial monitoring. The subjects were 97 healthy, untreated 35- to 45-year-old-men (34 normotensive, 29 borderline hypertensive, and 34 mild hypertensive). At 10-year follow-up, echocardiography was performed to 86 (89%) of them. Subjects not taking antihypertensive medication (n = 66) were included in the prediction of LVMI(g m-2). Echocardiography data at baseline was available from 70 (72%) of the subjects, of whom 52 did not use antihypertensive medication at follow-up. Pulse pressure (PP) at supine test (r = 0.337, P = 0.006), PP at dynamic exercise last work load (r = 0.332, P = 0.006), and PP after dynamic exercise (r = 0.316, P = 0.010) were the best BP variables achieved in tests in predicting future LVMI of the 66 subjects. Casual BP did not significantly correlate with future LVMI. The best model in predicting LVMI included PP achieved after dynamic exercise, family history of hypertension, and body mass index (BMI) (adj.R2 = 0.207). Baseline LVMI correlated significantly with future LVMI only among the 52 unmedicated subjects (r = 0.508, P<0.0001). The predictive value of baseline LVMI on future LVMI among them (adj.R2 = 0.243) was best improved by PP achieved in supine test and age (adj.R2 = 0.350). In conclusion, BP measurements during tests improved the prediction of LVMI compared with casual BP. For the first time, the pulsatile component of BP in tests was found to be the most significant BP parameter in predicting future LVMI.

Bile flow to the duodenum is reduced in hypothyreosis and enhanced in hyperthyreosis

Disturbances in sphincter of Oddi (SO) function may prevent normal bile flow and thus enhance probability of common bile duct stone (CBDS) formation. We have previously shown increased prevalence of diagnosed hypothyroidism in CBDS patients, which may be explained by thyroxine-induced inhibition of SO contractility, in addition to previously suggested changes in bile composition and hepatocytic excretion. The aim of this study was to investigate biliary dynamics in relation to altered thyroid gland function in rat, a rodent without a gallbladder. Euthyroid, hypothyroid or hyperthyroid Spraque-Dawley rats were anaesthetized with i.p. urethane, and exsanguinated at 15, 45, or 60 min after intravenous 99mTc HIDA injection. At these timepoints, the bile flow to intestine was determined by measuring the relative intestine vs. liver radioactivity. At 45 min this was 44% lower in hypothyroid rats and at 60 min 73% higher in hyperthyroid rats compared to euthyroid rats, while hepatic radioactivity at 15 min and blood pressure at injection were similar in the groups. We conclude that the bile flow to duodenum is reduced in hypothyreosis and enhanced in hyperthyreosis.

Can blood pressure responses to tests unmask future blood pressure trends and the need for antihypertensive medication? Ten years of follow-up

An exaggerated blood pressure (BP) response to test may unmask the subjects who have a high risk of developing hypertension. In this prospective 10 years of follow-up, we examined whether the predictive value of casual BP measurements on future BP level and need for antihypertensive medication could be improved by using BP responses to different physical tests. At baseline, BP was recorded by casual measurements and intra-arterial monitoring. During the intra-arterial BP recording, standardized postural and exercise tests were performed on 97 healthy, untreated men (34 normotensive, 29 borderline hypertensive, and 34 mild hypertensive). After 10 years of follow-up, 87 of them (90%) returned for casual and non-invasive 24-h BP measurements. At follow-up, 20 (23%) of the men had antihypertensive medication. The prediction of casual systolic blood pressure (SBP) was best improved by SBP at 10 min after the dynamic exercise test (adj. R2 = 0.448; adj. R2 = 0.356 for casual SBP alone). The prediction of casual diastolic blood pressure (DBP) was most improved by DBP at 10 min after the dynamic exercise test (adj. R2 = 0.282; adj. R = 0.259 for casual BP alone). SBP in the supine test best improved the prediction of 24-h SBP (adj. R2 = 0 448; adj. R2 = 0.275 for casual SBP alone). DBP in the standing test best improved the prediction of 24-h DBP (adj. R2 = 0.252; adj. R2 = 0.214 for casual DBP alone). Pre-exercise DBP and casual SBP were the best predictors of the need for antihypertensive medication (Cox-Snell R2 = 0.256; Cox-Snell R2 = 0.164 for casual SBP alone). In conclusion the prediction of future BP and need for antihypertensive medication can be improved by using BP measurements during postural and exercise tests. Future SBP is more predictable than DBP.

Effect of peritoneal dialysis on gastric myoelectrical activity in patients with chronic renal failure

Impaired gastric myoelectrical activity has been reported in patients with chronic renal failure (CRF). The effect of peritoneal dialysis on this function has not previously been described. The aim here was to investigate the effect of peritoneal dialysis on gastric myoelectrical activity. Gastric myoelectrical activity was recorded by electrogastrography (EGG) in 23 patients with CRF (18 with dyspepsia) during peritoneal dialysis and with the peritoneal cavity empty of dialysis fluid (14 patients), and in 20 healthy controls. Two 30-min EGG recordings before and after a solid test meal were analyzed using spectral analysis methods. No significant difference in the percentage of normal 2- to 4-cpm slow waves was found in patients on peritoneal dialysis compared to those with the peritoneal cavity empty of dialysis fluid or to controls (in fasting state 83 +/- 3%, 80 +/- 5% and 89 +/- 4%, in fed state 91 +/- 3%, 86 +/- 4% and 83 +/- 4%, respectively). It was found that the power ratio (change in power of normal slow waves in fed state) was significantly higher in the 14 patients on peritoneal dialysis compared to the same patients with the peritoneal cavity empty of dialysis fluid (27.2 +/- 10.7 vs 8.6 +/- 4.8, P < 0.05). There was no significant difference in the power ratio between patients with the peritoneal cavity empty of dialysis fluid and controls (8.6 +/- 4.8 vs 7.5 +/- 2.2). The subgroup of patients with no dyspepsia had a significantly higher power ratio compared to those with dyspepsia both on dialysis and with the peritoneal cavity empty of dialysis fluid (39.4 +/- 13.7 vs 12.4 +/- 5.2 and 29.2 +/- 21.5 vs 2.8 +/- 0.4 respectively, P < 0.05). In conclusion, there was no significant difference in gastric myoelectrical activity between patients with the peritoneal cavity empty of dialysis fluid and controls. Dialysis fluid in the peritoneal cavity seems to enforce the gastric myoelectrical signal.

Inhaled fluticasone decreases bronchial but not alveolar nitric oxide output in asthma

Exhaled nitric oxide (NO) concentration is a noninvasive measure of airway inflammation and is increased in asthma. Inhaled glucocorticoids decrease exhaled NO concentration, but the relative contributions of alveolar and bronchial levels to the decrease in exhaled NO concentration are unknown. Alveolar NO concentration and bronchial NO flux can be separately approximated by measuring exhaled NO at several exhalation flow rates. The effect of steroid treatment on alveolar and bronchial NO output in asthma was studied. Alveolar NO concentration and bronchial NO flux were assessed in 16 patients with asthma before and during treatment with inhaled fluticasone for 8 weeks and in 16 healthy controls. Before the treatment, asthmatics had increased bronchial NO flux (mean+/-SEM: 3.6+/-0.4 versus 0.7+/-0.1 nL x s(-1), p<0.001) but normal alveolar NO concentration (1.2+/-0.5 versus 1.0+/-0.2 parts per billion (ppb), p>0.05) compared with controls. Inhaled fluticasone decreased bronchial NO flux from 3.6+/-0.4 to 0.7+/-0.1 nL x s(-1) (p<0.01) but had no effect on alveolar NO concentration (before: 1.2+/-0.5; after: 1.2+/-0.1 ppb, p>0.05). The forced expiratory volume in one second improved, whereas asthma symptom score and serum levels of eosinophil cationic protein and eosinophil protein X decreased during the treatment. In conclusion, inhaled fluticasone decreases bronchial but not alveolar nitric oxide output simultaneously with clinical improvement in patients with asthma.

Estimation of frequency shift in cardiovascular variability signals

Spectral analysis of heart rate (HR) and blood pressure (BP) oscillations has traditionally concentrated on spectral power, although a shift in spectral frequency characterises the variability better than power in some cases. Experimental data were obtained from 14 healthy males in control and pharmacological blockade conditions. When parasympathetic control was reduced, LF oscillations of HR and BP tend to shift towards lower frequencies. Three parameters were compared to estimate the spectral shift within the low frequency (LF, 0.04-0.15 Hz) band in HR and BP variability: mean (fmean), median (fmed), and central frequency (fc). Parameter variance (pSTD) and sensitivity to noise were also estimated using realistic HR, systolic BP (SBP) and diastolic BP (DBP) data. fmean showed the lowest parameter variance both for an autoregressive (AR) method (SBP pSTD 3.1 vs 4.8 vs 4.7 mHz for fmean, fmed and fc, respectively; p<0.001) and an FFT method (SBP pSTD 4.7 vs 7.7 mHz for fmean and fmed, respectively; p<0.001). Furthermore, fmean was least sensitive to noise. fc showed the poorest performance being especially sensitive to noise. To analyse the spectral shift, fmean is preferred, since it performs better than fc, which has been used in most previous studies. To quantify the frequency of oscillations in cardiovascular signals, the mean frequency is recommended, with analyses across different spectral bands.

TERVA: system for long-term monitoring of wellness at home

Long-term monitoring of physiological and psychosocial variables in out-hospital conditions would be beneficial for investigating changes in wellness status of an individual or to understand interaction between physiological and behavioral processes. We aimed to design a personal wellness monitoring system (TERVA), which would allow monitoring of wellness-related variables at home for several weeks or even months. The designed TERVA system runs on a laptop computer and interfaces with different measurement devices through a serial interface. Measured variables include beat-to-beat heart rate, motor activity, blood pressure, weight, body temperature, respiration, ballistocardiography, movements, and sleep stages. In addition, self-assessments of daily well-being and activities are stored by keeping a behavioral diary. To test the system, one healthy man used the system for 10 weeks. The system was successfully applied in out-hospital conditions. The success rate of the measurements was 70-91%, depending on the variable under consideration. The pilot study indicated that the recorded data accurately reflected the health status of the subject. The TERVA system provides a method to record and investigate wellness-related data over several weeks, or even months, outside the hospital among subjects capable of using a personal computer. Several applications of the system are discussed.

Extended exhaled NO measurement differentiates between alveolar and bronchial inflammation

Lower respiratory tract inflammation can be detected by measuring exhaled nitric oxide (NO) concentration at a single exhalation flow rate, but this does not differentiate between alveolar and bronchial NO production. We assessed alveolar NO concentration and bronchial NO flux with an extended method of measuring exhaled NO at several exhalation flow rates in 40 patients with asthma, 17 patients with alveolitis, and 57 healthy control subjects. Bronchial NO flux was higher in asthma (2.5 +/- 0.3 nl/s, p < 0.001) than in alveolitis (0.7 +/- 0.1 nl/s) and healthy control subjects (0.7 +/- 0.1 nl/s). Alveolar NO concentration was higher in alveolitis (4.1 +/- 0.3 ppb, p < 0.001) than in asthma (1.1 +/- 0.2 ppb) and healthy control subjects (1.1 +/- 0.1 ppb). In asthma, bronchial NO flux correlated with serum level of eosinophil protein X (EPX) (r = 0.60, p < 0.001) and bronchial hyperresponsiveness (r = 0.55, p < 0.001). In alveolitis, alveolar NO concentration correlated inversely with pulmonary diffusing capacity (r = -0.55, p = 0.022) and pulmonary restriction. Glucocorticoid treatment or allergen avoidance normalized bronchial NO flux in asthma and decreased alveolar NO concentration toward normal in alveolitis. In conclusion, extended exhaled NO measurement can be used to separately assess alveolar and bronchial inflammation and to assess disease activity/severity in asthma and alveolitis.

Renal follow up of premature infants with and without perinatal indomethacin exposure

AIMS

To evaluate early childhood renal growth, structure, and function in children born at less than 33 weeks gestation and to investigate possible independent effects of perinatal indomethacin exposure.

METHODS

A total of 66 children born at less than 33 weeks gestation, 31 of them with perinatal indomethacin exposure (study group) and 35 without (control group), were examined at 2-4 years of age. Serum cystatin C and protein; plasma creatinine, sodium, and potassium; urine protein, calcium:creatinine ratios, and alpha(1) microglobulin; and glomerular filtration rate (GFR) were determined. Renal sonography examinations were performed.

RESULTS

The mean serum cystatin C concentrations were slightly higher in the control group than in the study group. Mean values of serum protein, and plasma creatinine and sodium did not differ between the groups, neither did median plasma potassium concentrations and urine protein:creatinine and calcium:creatinine ratios. None had tubular proteinuria. Abnormal GFR (<89 ml/min/1.73 m(2)) was found in one case in each group and renal structural abnormalities in five in each group. In logistic regression analysis the duration of umbilical artery catheter (UAC) use and furosemide treatment emerged as the significant independent risk factors for renal structural abnormalities. Furosemide treatment and assisted ventilation remained the risk factors associated with renal abnormalities in general-that is, functional and/or structural abnormal findings.

CONCLUSION

Perinatal indomethacin does not seem to affect long term renal growth, structure, or function in children born at less than 33 weeks gestation. Duration of UAC use, furosemide treatment, and assisted ventilation may be correlated with later renal structural and functional abnormalities.

Can stroke volume and cardiac output be determined reliably in a tilt-table test using the pulse contour method?

The applicability of the finger pressure-derived pulse contour (PC) technique was evaluated in the measurement of stroke volume (SV), cardiac output (CO) and their changes in different phases of the tilt-table test. The reference method was whole-body impedance cardiography (ICG). A total number of 40 physically active patients, aged 41 +/- 19 years, were randomly chosen from a pool of 230. Specifically speaking, 20 of the patients experienced (pre)syncope (tilt+ patients) during the head-up tilt (HUT), and 20 did not (tilt-). A total number of three measurement periods, 30-60 s each, were analysed: supine position, 5 min after the commencement of HUT, and 1 min before set down. SV and CO values measured by PC underestimated significantly those measured by ICG (biases +/- SD 19 +/- 14 ml and 1.55 +/- 1.14 l min-1, respectively) in agreement with earlier reports. The bias between the methods was almost the same in the different phases of the test. However, the SD of the bias was bigger for tilt+ (P < 0.05). When the bias between the methods was eliminated by scaling the first measurement to 100%, the agreement between the methods in the second and third measurements was clearly better than without scaling. Both methods showed a physiological drop in SV after the commencement of HUT. These results indicate that PC suffices in tracking the changes in CO and SV, but for absolute values it is not reliable.

Nephrotic syndrome, hyperreninemia and multiple transplant renal arterial stenoses in a patient with diabetes

Nine months after cadaveric renal transplantation the nephrotic syndrome developed in a patient with insulin-dependent diabetes. Renal biopsy ruled out tissue lesions induced by cyclosporine, chronic rejection, recurrence of diabetic kidney disease and de novo glomerulopathies. Captopril-enhanced nephrography and a high plasma renin response suggested renal artery disease. Angiography revealed five intrarenal arterial stenoses. Four were successfully dilated with a prompt diuretic response and diminished proteinuria. Late angiography showed a moderate restenosis in two of the dilated arteries. Due to persistent proteinuria, elevated blood pressure and higher serum creatinine levels than at nadir after transplantation low-dose ACE inhibitor therapy was started. This normalized proteinuria, blood pressure and serum creatinine levels. This beneficial response to combined renal artery balloon angioplasty and medical treatment has been sustained for 2.5 years.

Influences of nonselective, beta(1)-selective and vasodilatory beta(1)-selective beta-blockers on arterial pulse wave velocity in normotensive subjects

beta-Adrenoceptor blockers with disparate properties may have differential influences on arterial pulse wave velocity (PWV). Therefore, influences of single medium doses of bisoprolol, propranolol and celiprolol on PWV were compared in healthy subjects. Arterial PWV was obtained from the time delay between flow pulses measured from the root of the aorta and the popliteal artery. Bisoprolol and propranolol decreased arterial PWV more than placebo (P less-than-or-equal to .002) and celiprolol (P<.0001). In conclusion, the acute effects of bisoprolol and propranolol on arterial PWV in normotensive subjects seem to differ from that of celiprolol.

Renal function and blood pressure five years after puumala virus-induced nephropathy

BACKGROUND

Nephropathia epidemica (NE) is a mild form of hemorrhagic fever with renal syndrome caused by Puumala hantavirus. Its long-term prognosis is considered favorable. Some reports suggest, however, that a previous hantavirus infection increases the risk of hypertension.

METHODS

We studied 46 previously healthy subjects (26 males and 20 females, mean age of 44 years) who had serologically confirmed NE three to seven years previously, and 38 healthy, seronegative controls (22 males and 16 females, mean age of 44 years). Ambulatory blood pressure (ABP) was monitored. Glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were determined by 51CrEDTA and 131I-hippurate clearances, respectively. The filtration fraction (FF) was calculated. Quantitative 24-hour urinary protein excretion (UprotE) and timed overnight urinary excretion of alpha1-microglobulin were measured.

RESULTS

The NE patients had a higher mean ambulatory systolic BP than the controls (123 +/- 13 vs. 117 +/- 9 mm Hg, P = 0. 008). GFR and FF were increased in patients compared with controls (GFR, 120 +/- 20 vs. 109 +/- 14 mL/min/1.73 m2, P = 0.006; FF, 19 +/- 3 vs. 18 +/- 3%, P = 0.030), but ERPF did not differ between the groups. The patients also had higher UPE than the controls (median 0. 18 g/day, range 0.12 to 0.38 vs. median 0.14 g/day, range 0.09 to 0. 24, P < 0.001, respectively). The overnight urinary excretion rate of alpha1-microglobulin exceeded 7 microg/min in nine patients.

CONCLUSION

Three to seven years after NE, the patients had higher GFR and FF, more proteinuria, and higher ambulatory systolic BP compared with the healthy controls. NE may thus cause mild renal lesions and alterations in BP in some patients.

Increased bronchial nitric oxide production in patients with asthma measured with a novel method of different exhalation flow rates

The concentration of nitric oxide (NO) in exhaled air is increased in patients with asthma, suggesting that measuring fractional exhaled NO concentration (FE(NO)) may be used to monitor asthmatic airway inflammation. However, increased FE(NO) is not specific for asthma, as other inflammatory lung diseases may also increase FE(NO). To augment the specificity of FE(NO) measurement, we tested a novel theoretical modelling of pulmonary NO dynamics that allows the approximation of alveolar NO concentration and bronchial NO flux separately by measuring FE(NO) at several exhalation flow rates. We measured FE(NO) at four exhalation flow rates in 10 steroid-naive asthmatics, 5 patients with extrinsic allergic alveolitis, and in 10 healthy controls. Both the asthmatics and the patients with alveolitis had significantly higher FE(NO) than the healthy controls. The increased NO concentration originated from the bronchial level in the asthmatics and from the alveolar level in the patients with alveolitis. In the second part of the study we assessed the repeatability of FE(NO) test, within-day and day-to-day (during two weeks) variation in FE(NO), and the effects of mouth pressure and cigarette smoking on FE(NO) in healthy volunteers. Repeatability of 10 subsequent measurements was high (coefficient of variation (CV) 4.6% +/- 0.4%), and no diurnal variation was found. The day-to-day variation during a 2-week period gave a CV of 10.6% +/- 1.0%. The magnitude of mouth pressure (5-20 cmH2O in adults, 5-40 cmH2O in children) during measurement had no effect on FE(NO). Smoking a cigarette caused a small and transient but statistically significant increase in FE(NO) at 1 and 5 min after smoking. In conclusion, FE(NO) measurement is highly repeatable with low day-to-day variation among healthy subjects. Our results also suggest that the present novel method of measuring FE(NO) at several exhalation flow rates can be used to approximate alveolar and bronchial contributions to FE(NO) separately and thus increase the clinical value of this test.

Wide-band spectral analysis of blood pressure and RR interval variability in borderline and mild hypertension

The aim of this study was firstly to investigate whether indices of wide-band spectral analysis in borderline hypertensive (BHT) or mildly hypertensive (HT) subjects differ from those in normotensive (NT) subjects, and secondly to assess the predictive value of these indices for future hypertension. Electrocardiogram and intra-arterial 24 h ambulatory blood pressure (BP) were recorded in 32 NT, 29 BHT and 30 HT middle-aged men. From the recordings, a 16 h period was extracted for wide-band spectral analysis. A single spectrum of BP and RR interval (RRI) variability was computed for each period by the fast Fourier transform method. The slopes of the spectra were assessed on a log-log scale by linear fitting of the spectral values. Power spectral densities were calculated over regions of 0-0.003, 0.003-0.04, 0.04-0.15, 0.15-0.40 and 0-0.4 Hz. No between-group differences were found in the slopes of BP and RRI spectra. The between-group differences in spectral powers for BP variability were almost invariably significant. The spectral powers for RRI variability did not show between-group differences. Five years later, 22 NT, 22 BHT and 18 HT subjects were re-assessed using casual BP measurements. In a logistic regression model for the combined group of NT and BHT subjects who became HT (22 of 44) during the five-year period, none of the parameters of wide-band spectrum predicted the development of hypertension. In conclusion, parameters of wide-band spectral analysis may not be useful in predicting future hypertension in NT and BHT subjects. Because the BP level is a major factor influencing BP variability, the between-group differences in wide-band spectral powers in BP may be due to differences in BP level rather than differences in cardiovascular regulatory mechanisms.

Circadian profile of low-frequency oscillations in blood pressure and heart rate in hypertension

Electrocardiogram and intraarterial blood pressure (BP) were recorded in 35 normotensive (NT), 29 borderline hypertensive (BHT), and 30 mildly hypertensive (HT) men (aged 35 to 45 years) by the Oxford method over a 24-h period. Consecutive data segments of 5 min were extracted from the recordings for frequency domain analysis. Heart rate (HR) and BP variability was calculated for oscillations between 0.05 and 0.12 Hz, usually referred to as Mayer waves. Power and median frequency of the oscillations were determined. Some 10% of the segments were excluded from the analysis because of artifacts and transients. The results were averaged for 5-h periods in the evening, at night, and during the day. In the BHT subjects, the median frequency of the Mayer waves was shifted to lower frequencies as compared with the NT subjects. This was seen at night and during the day. The phenomenon presumably reflects an increased latency in the sympathetic vasomotor control of the baroreceptor reflex. No between-group differences were found in the normalized spectral power values. Five years later, 24 NT, 22 BHT, and 19 HT subjects were reassessed using casual BP and noninvasive ambulatory 24-h monitoring. In the initial phase, the median frequencies for the 5-h periods showed no evident linear relationship with the corresponding BP levels. However, the median frequencies showed high inverse correlations with the follow-up ambulatory BP levels. In the evening and during the day, the median frequency showed a significant inverse correlation also with the increment in BP. No clear relationship was found between power estimates and BP levels or future increments in BP. In conclusion, the frequency shift of Mayer waves to lower frequencies is associated with an increased risk of developing established hypertension.

Psychological and physiological characteristics of sweet food "addiction"

OBJECTIVE

Drug addicts in general can be distinguished from nonaddicts by their affective and physiological and craving responses to drug-related cues. The purpose of this study was to examine similar affective, physiological, and behavioral variables in chocolate "addicts" and control subjects.

METHODS

Sixteen addicts and 15 control subjects took part in two laboratory experiments in which their heart rate, salivation, and self-reported responses were measured.

RESULTS

In the presence of external chocolate cues, chocolate addicts were more aroused, reported greater cravings, experienced more negative affect, and also ate more chocolate than control subjects. Self-report measures on eating attitudes and behavior, body image, and depression confirmed that a relationship exists between "chocolate addiction" and problem eating. Chocolate addicts showed more aberrant eating behaviors and attitudes than controls, and were also significantly more depressed.

DISCUSSION

Chocolate addicts may be considered to be a parallel with addicts generally, because they differ from controls in craving for chocolate, eating behavior, and psychopathology (in respect of eating and affect).

Long-term effects of transduodenal sphincterotomy: symptoms and hepatobiliary function

BACKGROUND/AIMS

Endoscopic sphincterotomy is widely used in treating common bile duct stones, but the long-term effects of destroying the sphincter of Oddi are not known. This study investigated the long-term (15-20 years) effects of transduodenal sphincterotomy on gastrointestinal symptoms and hepatobiliary function in a retrospective controlled study.

METHODOLOGY

Between 1974 and 1977, choledocholithotomy was performed in 131 patients either transduodenally (60 patients) or via choledochotomy (71 patients). For the retrospective part of the study, all hospital records, death certificates and autopsy reports were reviewed. Twenty-seven patients who could be reached and volunteered to participate (12 and 15, respectively) were re-examined. In the re-examination part of the study, a standard questionnaire interview, laboratory tests, quantitative cholescintigraphy and ultrasonography were performed.

RESULTS

The hospital mortality for the primary operations was 0.8%, 0% for the transduodenal sphinterotomies and 2% for the choledochotomies; the difference was not significant. During the follow-up period, no significant differences could be seen in the death rate or in the causes of death between the study groups. During re-examination, flatulence was found to be more common in the choledochotomy subgroup (7/15 vs 2/12, p<0.05). In the laboratory tests, conjugated bilirubin and serum aspartate amino transferase levels were higher in the transduodenal subgroup than in the choledochotomy subgroup (3.3 umol/L, SD 0.4 vs 2.2 umol/L, SD 0.2, p<0.02; and 25 U/L, SD 12.6 vs 18.6 U/L, SD 5.0, p<0.05, respectively). Furthermore, 6/12 (50%) of the transduodenal subgroup had elevated serum alanine aminotransferase, aspartate aminotransferase or amylase levels, as compared to 1/15 (7%) in the choledochotomy subgroup (p<0.02). In terms of ultrasonography, in the choledochotomy subgroup, the common bile duct diameter was larger than 8 mm in 8/15 (53%) patients, as compared to 1/12 (8%) in the transduodenal subgroup (p<0.02). In terms of quantitative cholescintigraphy, in 9/12 (75%) patients of the transduodenal subgroup, the hilum-duodenum transit time was less than 10 minutes, as compared to 4/12 (47%) of the choledochotomy subgroup.

CONCLUSIONS

Transduodenal sphincterotomy results in decreased flatulence and enhanced common bile duct drainage, even in the long-term period, but slightly higher serum liver funtion tests, when compared to supraduodenal choledochotomy.

Outcome of patients operated on for esophageal atresia: 30 years' experience

PURPOSE

The aim of this study was to evaluate the outcome and late sequelae of patients with esophageal atresia or tracheoesophageal fistula.

METHODS

Sixty patients with esophageal atresia or tracheoesophageal fistula (EA-TEF) were treated in Tampere University Hospital in the years 1963 through 1993. Long-term outcome was evaluated with a questionnaire, pulmonary and esophageal function test results, 24-hour pH level monitoring, tracheobronchoscopy findings, and esophagogastroscopy with biopsy sections and samples for bacterial cultures.

RESULTS

One third of the respondents reported having impaired quality of life because of respiratory infections, dyspnea, and difficulties in swallowing and coughing at night. Eighteen percent had gastroesophageal reflux (GER) symptoms. The rate of symptoms decreased with age. Impaired pulmonary function, GER, abnormal esophageal peristalsis, and transit time were registered. Tracheobronchoscopy showed tracheal narrowing and inflammation in one third; in histopathologic analysis, however, the rate of inflammation was more than doubled. Histologically, esophageal inflammation was found in 51%, Barrett's esophagus in 6%, and a Helicobacter pylori infection in 21% of cases. The severity of GER, esophageal peristaltic abnormality, tracheal inflammation, and impairment of pulmonary function seems to be alleviated with age.

CONCLUSIONS

Although the long-term outcome of EA-TEF patients seems to be favorable, respiratory and gastrointestinal symptoms as well as functional abnormalities remain frequent. Gastric metaplasia in the esophagus and the high rate of tracheal, esophageal, and gastric inflammation indicate a need for long-term follow-up.

Influence of captopril, propranolol, and verapamil on arterial pulse wave velocity and other cardiovascular parameters in healthy volunteers

OBJECTIVE

The effects of antihypertensive agents on cardiovascular parameters, especially on arterial pulse wave velocity, remain largely unknown in normotensive subjects. Therefore, the present investigation was designed to evaluate acute effects of ACE inhibitor captopril,beta-adrenoceptor blocker propranolol and calcium entry blocker verapamil on cardiovascular and ventilatory function in healthy volunteers.

MATERIAL

The influence of single doses of captopril (25 mg), propranolol (40 mg), and verapamil (80 mg) on cardiovascular function and exercise capacity were compared in healthy volunteers in a randomized, double-blind, placebo-controlled fashion.

METHODS

Cardiac output and beat-by-beat blood pressure were estimated non-invasively before and after the drug administrations by whole-body impedance cardiography and Finapres finger blood pressure monitoring, respectively. Arterial pulse wave velocity was obtained from the time delay between flow pulses measured from the root of the aorta and the popliteal artery, and systemic vascular resistance was calculated from cardiac output and mean arterial pressure. In addition, a progressive maximal exercise test was performed after the treatments.

RESULTS

Propranolol reduced heart rate, cardiac output and arterial pulse wave velocity, and increased systemic vascular resistance clearly more effectively than placebo. In addition, captopril effectively decreased arterial resistance and pulse wave velocity. However, the influence of verapamil on cardiovascular parameters did not significantly differ from those observed in placebo-treated subjects. Exercise peak heart rate, peak blood pressure, and minute ventilation were reduced in subjects treated with propranolol, but not in those treated with captopril and verapamil, when compared to placebo.

CONCLUSIONS

Acute administration of captopril and propranolol but not verapamil clearly modulated cardiovascular parameters in rest, suggesting differential effects of these compounds on cardiovascular function in healthy volunteers. These drugs seem to have disparate effects on arterial pulse wave propagation as an indicator of arterial compliance after short-term administration in healthy subjects. Captopril and verapamil had no effect on cardiovascular and ventilatory function during maximal exercise, while propranolol markedly altered also these variables in the present study.

Office and laboratory blood pressures as predictors of daily blood pressure level in normotensive subjects and borderline and mild hypertensive subjects

A series of standardized laboratory tests [10 min sitting and supine, 9 min standing, dynamic; cycle ergometer (ERG) and isometric exercise; handgrip (HG)] were performed during intra-arterial blood pressure (BP) recording in 97 healthy unmedicated men, initially classified as normotensive (NT, n = 34), borderline hypertensive (BHT, n = 29) or mildly hypertensive (HT, n = 34) by repeated office blood pressure (OBP) measurements. After testing, a 24-h intra-arterial ambulatory BP (IABP) recording was obtained while subjects performed their normal activities. Day and night periods were analysed as well as 24-h averages for systolic BP (SBP) and diastolic BP (DBP) using Pearson correlations and multiple linear regressions. In normotensive subjects, the supine SBP predicted IABP measurements best (r range 0.39-0.69, P < 0.05-0.001). In multiple regression, supine SBP explained 49% of 24-h SBP variance (F = 12.4, P = 0.001). For BHT, supine SBP was also the best predictor (r range 0.09-0.64, P NS to P < 0.001), and it explained 37% of 24-h SBP variance (F = 15.6, P = 0.0005). In HT, ERG DBP correlated best with IABP (r range 0.52-0.75, P < 0.01-0.001). ERG SBP explained 49% of 24-h SBP (F = 31.0, P = 0.0000) and ERG DBP explained 56% of 24-h DBP (F = 35.4, P = 0.0000) variance. Laboratory BP correlations were generally better with day than with night measurements. OSBP correlated moderately well with IABP in NT, and weakly in BHT and HT; ODBP instead correlated with IABP in NT and HT but not significantly in BHT. In conclusion, OBP is less closely related to IABP than laboratory BP, but even laboratory BP generally explains less than 50% of IABP variance. Stressors such as exercise are useful only in HT. For BHT, the prediction of IABP with laboratory measures was even weaker than in other groups, and thus ambulatory measurements cannot be replaced by short-duration laboratory measurements and stress tests.

Correct utilization of exercise electrocardiographic leads in differentiation of men with coronary artery disease from patients with a low likelihood of coronary artery disease using peak exercise ST-segment depression

In this study we compared the diagnostic characteristics of the individual exercise electrocardiographic leads, 3 different lead sets comprising standard leads and the effect of the partition value in the detection of coronary artery disease (CAD). The diagnostic variable used was ST-segment depression at peak exercise, and the study population consisted of 101 patients with CAD and 100 patients with a low likelihood of the disease. The lead system used was the Mason-Likar modification of the standard 12-lead system and exercise tests were performed on a bicycle ergometer. The comparisons were performed by means of receiver-operating characteristic analysis and by determining sensitivities at a fixed 95% specificity. These properties, defined here as diagnostic capacity, were the most efficacious in leads I, -aVR, V4, V5, and V6. Diagnostic capacities in leads aVL, aVF, III, V1, and V2 were quite poor; statistical comparisons indicated significant differences between these leads and lead V5 (p < or = 0.0001 in each case). Use of the maximum value of ST-segment depression at peak exercise derived from all 12 leads produced a considerable decrease in the diagnostic capacity of the exercise electrocardiogram compared with lead V5. The exclusion of leads aVL, V1, and III improved the diagnostic capacity compared with the 12-lead set, but it was still smaller than that of lead V5. With use of a lead set with the 5 best leads increased the diagnostic capacity over other lead sets and over any individual lead. Further improvement was noted when a 50% smaller partition value was applied to leads I and -aVR than for the other leads (p = 0.041). In conclusion, this study suggests that use of leads I, -aVR, V4, V5, and V6 is the most influential when differentiating between patients with CAD and patients with a low likelihood of disease using peak exercise ST-segment depression. The effective use of leads I and -aVR requires the partition value applied for these leads to be 50% smaller than that used for the lateral precordial leads.

Effect of ST segment measurement point on performance of exercise ECG analysis

To evaluate the effect of ST-segment measurement point on diagnostic performance of the ST-segment/heart rate (ST/HR) hysteresis, the ST/HR index, and the end-exercise ST-segment depression in the detection of coronary artery disease, we analysed the exercise electrocardiograms of 347 patients using ST-segment depression measured at 0, 20, 40, 60 and 80 ms after the J-point. Of these patients, 127 had and 13 had no significant coronary artery disease according to angiography, 18 had no myocardial perfusion defect according to technetium-99m sestamibi single-photon emission computed tomography, and 189 were clinically 'normal' having low likelihood of coronary artery disease. Comparison of areas under the receiver operating characteristic curves showed that the discriminative capacity of the above diagnostic variables improved systematically up to the ST-segment measurement point of 60 ms after the J-point. As compared to analysis at the J-point (0 ms), the areas based on the 60-ms point were 89 vs. 84% (p=0.0001) for the ST/HR hysteresis, 83 vs. 76% (p<0.0001) for the ST/HR index, and 76 vs. 61% (p<0.0001) for the end-exercise ST depression. These findings suggest that the ST-segment measurement at 60 ms after the J-point is the most reasonable point of choice in terms of discriminative capacity of both the simple and the heart rate-adjusted indices of ST depression. Moreover, the ST/HR hysteresis had the best discriminative capacity independently of the ST-segment measurement point, the observation thus giving further support to clinical utility of this new method in the detection of coronary artery disease.

The effect of lead selection on traditional and heart rate-adjusted ST segment analysis in the detection of coronary artery disease during exercise testing

Several methods of heart rate-adjusted ST segment (ST/HR) analysis have been suggested to improve the diagnostic accuracy of exercise electrocardiography in the identification of coronary artery disease compared with traditional ST segment analysis. However, no comprehensive comparison of these methods on a lead-by-lead basis in all 12 electrocardiographic leads has been reported. This article compares the diagnostic performances of ST/HR hysteresis, ST/HR index, ST segment depression 3 minutes after recovery from exercise, and ST segment depression at peak exercise in a study population of 128 patients with angiographically proved coronary artery disease and 189 patients with a low likelihood of the disease. The methods were determined in each lead of the Mason-Likar modification of the standard 12-lead exercise electrocardiogram for each patient. The ST/HR hysteresis, ST/HR index, ST segment depression 3 minutes after recovery from exercise, and ST segment depression at peak exercise achieved more than 85% area under the receiver-operating characteristic curve in nine, none, three, and one of the 12 standard leads, respectively. The diagnostic performance of ST/HR hysteresis was significantly superior in each lead, with the exception of leads a VL and V1. Examination of individual leads in each study method revealed the high diagnostic performance of leads I and -aVR, indicating that the importance of these leads has been undervalued. In conclusion, the results indicate that when traditional ST segment analysis is used for the detection of coronary artery disease, more attention should be paid to the leads chosen for analysis, and lead-specific cut points should be applied. On the other hand, ST/HR hysteresis, which integrates the ST/HR depression of the exercise and recovery phases, seems to be relatively insensitive to the lead selection and significantly increases the diagnostic performance of exercise electrocardiography in the detection of coronary artery disease.

Frequency shift in baroregulatory oscillation in borderline hypertensive subjects

The aim of this study was to quantify the frequency shift in vasomotor oscillations in blood pressure we observed in borderline hypertensive individuals in our previous study. Electrocardiogram and intraarterial blood pressure were recorded in 33 normotensive, 29 borderline hypertensive, and 33 mildly hypertensive men (aged 35 to 45 years). Five-minute stationary periods in supine, sitting, and standing positions, and during sleep were extracted from the recordings for autoregressive frequency domain analysis. In borderline hypertensive subjects vasomotor oscillations in the range of 0.05 to 0.12 Hz in blood pressure and heart rate, assumed to be associated with baroreceptor activity, were shifted to lower values as compared with the other two groups. The frequency shift was assessed by median frequency of the oscillations. Significant between-group differences were observed in the supine and sitting positions. No significant between-group differences were seen in normalized spectral power estimates. Further studies are required to determine whether the frequency shift provides prognostic information on cardiovascular morbidity.

Variation of ambulatory blood pressure in healthy middle-aged men

The majority of the reference data on ambulatory blood pressure (ABP) monitoring is based on fixed, predefined times for waking hours and sleep. Our aim was to determine the level of ABP according to diary entries when awake, at work, at home and during sleep in a sample of normotensive, middle-aged men. The dipping-status was also determined. All measurements were taken with a non-invasive auscultatory device on a normal working day. A total of 62 clinically healthy, normotensive men without a history of elevated BP were included. The mean resting BP of the group was 122/73 mm Hg. The 24-h systolic BP (SBP) was 114.4 +/- 8.6 mm Hg (95% CI 112.3, 116.6), while the diastolic BP (DBP) was 80.4 +/- 7.2 mm Hg (95% CI 78.5, 82.2). SBP when awake was 120.5 +/- 9.4 mm Hg (95% CI 118.1, 122.9) and diastolic pressure 84.4 +/- 7.7 mm Hg (95% CI 82.5, 86.4). The corresponding values for systolic and diastolic pressures during sleep were 101.2 +/- 8.5 mm Hg (95% CI 99.1, 103.4) and 71.7 +/- 7.7 mm Hg (95% CI 69.7, 73.6). The difference between day and night was 19.2 +/- 7.0 mm Hg for systolic and 12.7 +/- 6.0 mm Hg for diastolic pressure. The number of men whose systolic and diastolic pressure dropped less than 10% while asleep (non-dippers) was eight (13%) and 15 (24%), respectively. If the mean +/- 2 standard deviation interval is considered, the range of normality averaged 102-139/69-100 mm Hg when awake, 84-118/56-87 mm Hg when asleep and 97-132/66-95 over 24 h. The awake-sleep pressure difference did not correlate with the 24-h average.

Blood pressure responses to exercise as predictors of blood pressure level after 5 years

There is considerable disagreement in the literature on the clinical usefulness of exercise testing as a tool for prediction of future hypertension. Much of the discrepancy between various reports is attributable to the difficulties of blood pressure (BP) measurement during exercise. Therefore, we investigated whether accurate intraarterial BP measurement will increase the predictive power of exercise testing. The BP responses to dynamic and isometric exercise were evaluated in 97 healthy, unmedicated men, of whom 34 were normotensive (NT), 29 borderline (BHT), and 34 mildly hypertensive (HT) using three criteria: 1) achieved BP during the test, 2) the change of the BP from baseline to exercise, and 3) the group was divided into high responders (HIGH, n = 19, systolic BP > or = 220 and diastolic BP > or = 105 mm Hg) and normal responders (n = 60). Five years later the BP was reassessed by casual measurements and noninvasive ambulatory 24-h monitoring (NAMB) in 79 (81%; 27 NT, 24 BHT, and 28 HT) subjects. The achieved isometric BP correlated well with the follow-up BP (casual systolic BP r = 0.43, diastolic BP r = 0.45, and NAMB systolic BP r = 0.44, diastolic BP r = 0.58, P < .001). However, achieved dynamic BP showed a poorer relationship to future BP (r range, 0.09 to 31, P = NS to P < .01). Because the intraarterial preexercise sitting BP also correlated well with follow-up BP (r range, 0.33 to 0.48, P < .01 to P < .001), and the r values were close to those of achieved isometric BP we used multiple regressions (including all resting and exercise BP values as independent variables) to evaluate the contributions of the baseline and exercise values for prediction of the follow-up BP. The baseline value explained 12% to 23% (from casual diastolic BP to NAMB diastolic BP, systolic BP values) of future BP variance, whereas achieved isometric BP ranged an additional 1% to 11% (from casual systolic BP to NAMB diastolic BP) of variance. In general, BP change from baseline with stressors did not correlate with follow-up measurements. In the high responder group the achieved dynamic BP did not correlate significantly with the follow-up BP, whereas the achieved isometric diastolic BP did correlate (casual diastolic BP r = 0.56, P < .05, NAMB systolic BP and diastolic BP r = 0.52, P < .05). Both groups had similar future BP levels. In conclusion, even with very accurate BP readings the reactivity to dynamic exercise is a weak predictor of future BP, and does not improve the prediction compared to resting BP values. Intraarterial BP response to isometric exercise marginally improves the prediction of future BP levels.

Intra-arterial blood pressure during exercise and left ventricular indices in normotension and borderline and mild hypertension

Our objective was to study the usefulness of BP responses to exercise compared to postural BP values for prediction of left ventricular (LV) indices in 28 normotensive (NT), 14 borderline hypertensive (BHT), and 24 mildly hypertensive (HT) men (aged 35-45 years) using intra-arterial BP, the "gold standard" measurement during a series of postures (10 min supine, 10 min sitting, 9 min standing), and exercise (isometric; hand grip, and dynamic; cycle ergometer). LV indices were studied by echocardiography. The highest postural BP correlation was obtained between LV mass index (LVMI) and standing systolic BP (SBP, r = .39, p < .01). Achieved exercise BP did not improve the result compared to standing BP (isometric SBP r = .41, p < .01, dynamic SBP r = .39, p < .01). When exercise responses were expressed as BP change (exercise BP-supine BP) they showed lower correlations with LVMI than achieved exercise BP readings. Using linear multiple regression including all the BP variables, the achieved SBP with isometric exercise explained 17% of LVMI variance (F = 12.9, p = .0006) without any additive value of other variable. In a forced linear regression using BP with various postures as the first variable, the achieved BP with dynamic exercise did not add to the explanation of LVMI variance. However the SBP during isometric exercise added 6% (F = 4.9, p < .05) for the explanation of LVMI variance with sitting SBP as baseline, and also 7% (F = 5.0, p < .05) with supine SBP and diastolic BP as baselines, but no additive value was seen with standing BP. We conclude, that BP levels during various postures were well related to LVMI. Achieved BP or BP change with dynamic exercise did not improve the prediction of the LVMI, and even the best single predictor, BP with isometric exercise, added only little to the power of prediction obtainable from postural values. With mild elevation of BP the clinical utility of dynamic exercise in evaluation of left ventricle is questionable whereas the utility of isometric exercise is marginal. Relatively low correlation values in this study suggest that BP is only one of many factors affecting the cardiac anatomy in the early phases of hypertension.

Blood pressure level and variability in the prediction of blood pressure after 5-year follow-up

We compared mean intra-arterial ambulatory blood pressure (IAMB), blood pressure (BP) diurnal profiles are variability, and postural measurements with casual sphygmomanometric measurements for the prediction of future BP. We studied 97 healthy, ummedicated men classified as normotensive (NT, n = 34), borderline hypertensive (BHT, n = 29), or mildly hypertensive (HT, n = 34) by repeated casual measurements during the 2 months before IAMB. Five years later, we reassessed 79 subjects (81%) using casual BP measurements and noninvasive ambulatory 24-hour BP monitoring (NAMB). IAMB level generally correlated well with follow-up BP and slightly better with NAMB level than with casual measurements (24-hour IAMB versus follow-up NAMB systolic BP [SBP], r = .64, P < .001; versus diastolic' BP [DBP], r = .52, P < .001). NT and BHT subgroup correlations were of similar strength, but the relationship in the HT subgroup was not significant. Similarly, when we examined daytime and nighttime BP levels, nighttime BP correlated better with follow-up BP in NT and BHT but not in HT. The only measures that were significantly related to follow-up BP in HT were two BP variability measures, SD and the range of variability (RV80: 90th minus 10th percentile), (initial 24-hour IAMB SD and follow-up BP, r = .42 to r = .52, P < .05 to P < .01; RV80 versus follow-up BP, r = .43 to r = .52, P < .05 to P < .01). Correlations of follow-up BP with postural BP were generally weaker than with casual BP or IAMB level. Linear stepwise regressions for SBP and DBP separately (including all IAMB variables) demonstrated that the best single predictor for follow-up BP was 24-hour IAMB SBP level, which explained 41% of follow-up NAMB SBP level variance (F = 52.6, P < .001). However, in a second analysis including casual values, casual SBP alone explained 44% of follow-up NAMB SBP variance (F = 62.5, P < .001), whereas IAMB SBP added only 4% (F = 5.5, P < .05). Predictions of follow-up DBP were always poorer. After 5 years, 70% of NT and 86% of HT were still in their initial classification group, but 67% of BHT had become hypertensive. In these new HT (n = 16), initial IAMB level correlated most strongly with follow-up NAMB level (24-hour SBP, r = .70, P < .01; 24-hour DBP, r = .55, P < .05). The only other significant demographic variable predicting future BP was change in weight over 5 years, which added 10% to the explanation of future casual SBP variance (F = 12.5, P = .0007) and 15% to casual DBP variance (F = 18.0, P = .0001); for NAMB, the percentages were lower. In logistic regression, those NT and BHT who became hypertensive (n = 22) had a 75% probability of becoming hypertensive if they gained 11.7 kg or more during 5 years (X2 = 4.5, P = .03). To conclude, BP tended to increase in all groups, especially in BHT, during follow-up. Nominal differences were observed between casual measurements and BP level measures in the prediction of future BP, and their explanatory value for future BP was generally less than 50%. However, for BHT who became hypertensive, BP level and variability measurements somewhat improved the prediction of follow-up BP. Weight gain was an important additional predictor for future hypertension in both NT and BHT.

Accurate detection of coronary artery disease by integrated analysis of the ST-segment depression/heart rate patterns during the exercise and recovery phases of the exercise electrocardiography test

In this comparative cross-sectional study, we evaluated whether a novel computerized diagnostic variable, ST-segment depression/heart rate ST/HR analysis during both the exercise and postexercise recovery phases of the exercise electrocardiography (ECG) test, can detect coronary artery disease more accurately than methods using either exercise or recovery phase alone. The study population comprised 347 clinical patients referred for a routine bicycle exercise ECG test at Tampere University Hospital, Finland. Of these, 127 had angiographically proven coronary artery disease, whereas 13 had no coronary artery disease according to angiography, 18 had no perfusion defect according to technetium-99m sestamibi single-photon emission computed tomography, and 189 were clinically normal with respect to cardiac diseases. For each patient, the maximum values of the ST/HR hysteresis, ST/HR index, end-exercise ST depression, and recovery ST depression were determined from the Mason-Likar modification of the standard 12-lead exercise electrocardiogram [aVL, aVR, and V1 excluded]. The diagnostic performance of these continuous diagnostic variables was compared by means of receiver-operating characteristic analysis. The area under the receiver-operating characteristic curve of the ST/HR hysteresis was 89%, which was significantly larger than that of the end-exercise ST depression (76%, p < or = 0.0001), recovery ST depression (84%, p = 0.0063), or ST/HR index (83%, p = 0.0023), indicating superior diagnostic performance of the ST/HR hysteresis independent of the partition value selection. In conclusion, computerized analysis of the HR-adjusted ST depression pattern during the exercise phase, integrated with the HR-adjusted ST depression pattern during the recovery phase after exercise, can significantly improve the diagnostic performance and clinical utility of the exercise ECG test for the detection of coronary artery disease.

Blood pressure levels and variability, smoking, and left ventricular structure in normotension and in borderline and mild hypertension

The aims of this study were to determine the importance of ambulatory blood pressure measurement, diurnal blood pressure (BP) profile, and variability in the evaluation of left ventricular (LV) parameters, and the impact of smoking on these factors. We performed intraarterial ambulatory BP (IAMB) recording and echocardiography in 80 healthy, unmedicated men aged 35 to 45 years. Based on repeated casual (CAS) readings before the study, the subjects were classified as normotensive (NT, n = 32), borderline hypertensive (BHT, n = 21), or mildly hypertensive (HT, n = 27) according to WHO criteria. There were 19 (8 NT/5 BHT/6 HT) smokers and 48 (18 NT/13 BHT/17 HT) nonsmokers. Both BHT and HT had significantly greater LV mass index (LVMI) than NT, but LVMI did not differ between nonsmokers and smokers. For the whole group, 24-h BP correlated somewhat better with LVMI than CAS BP (24-h IAMB SBP r = 0.44, P < .001, DBP r = 0.36, P < .001, and CAS SBP r = 0.35, P < .01, DBP r = 0.37, P < .001). Casual SBP alone explained 12% of LVMI variance (F = 10.7, P < .01), whereas 24-h IAMB SBP alone explained 19% of LVMI variance (F = 18.4, P < .001). When comparing day and night SBP and DBP levels, night SBP showed the closest correlation with LVMI (r = 0.43, P < .001), and this alone explained 18% of LVMI variance (F = 18.1, P < .001). Smokers had higher correlations between night BP and LVMI (SBP and DBP r = 0.56, P < .05) than nonsmokers (SBP r = 0.37, P < .01 and DBP r = 0.30, P < .05). In a multiple linear regression including all BP variables, for smokers, night DBP (although only marginally better than night SBP) was the best predictor, explaining 32% of LVMI variance (F = 10.6, P < .01) and additionally night DBP standard deviation (SD) added 18% to the prediction of LVMI (F = 5.8, P < .05). For nonsmokers, day SBP had closest correlation with LVMI (r = .43, P < .01), but explained only 19% of LVMI variance (F = 10.5, P < .01), and other measures did not increase the explanation. We conclude that ambulatory BP was slightly better than CAS BP in predicting LVMI, but BP level, also when measured with the best method available, explained only a moderate fraction of LVMI variance in mild hypertension. However, among smokers, BP, especially nighttime and BP variability, explained LV changes better than among nonsmokers. Thus smoking may have an impact on the interaction of ambulatory BP and LVMI, and in future studies more attention should be paid to this toxic factor.

Multivariate autoregressive model with immediate transfer paths for assessment of interactions between cardiopulmonary variability signals

Multivariate autoregressive modelling provides a method to analyse the dynamic interactions between heart rate (HR), blood pressure (BP) and respiration (RESP) by means of noise source contributions (NSCs). The conventional approach presumes the modelled noise sources are mutually independent. This presumption is, in general, not satisfied and causes an error in the results. In the present study, the effect of this error is analysed. A method is presented to remove the error by making the noise sources independent. The method is based on the inclusion of immediate transfer paths in the model. To quantify the strength of the interactions, a measure called NSC ratio (NSCR); is calculated; this states the amount of variability of the signal arising from other signals. The method is demonstrated by studying the inter-relationships between HR, BP and RESP in a healthy male subject in supine and standing positions. It is found that the error is marked and that the presented method provides corrected estimates for spectral decomposition and NSC analysis. The results show it is necessary to include the immediate transfer mechanisms in the model, while analysing the cardiopulmonary dynamics by means of HR and BP variability.

Glomerular filtration rate and kidney size after six years disease duration in non-insulin-dependent diabetic subjects

The objective of the present study was to estimate how glomerular filtration rate and kidney size change after six years of diabetes in subjects with non-insulin-dependent disease. It is a population-based prospective study of a cohort of non-insulin diabetic patients (n = 150) diagnosed 1985-1988. The baseline studies utilized a non-diabetic control group, whose basic characteristics were equal to the study group. The setting was a primary health care center in an urban area. Main outcome measures were the glomerular filtration rate and its relation to renal area, mean blood pressure, hemoglobin A1c, serum insulin and cholesterol. Seventeen patients had died and 109 were eligible for evaluation at follow-up. The mean (standard deviation) of the glomerular filtration rate (ml/min/1.73 m2) remained elevated at follow-up, 118 (28), just as it was at baseline, 118 (28) in the diabetic subjects compared to matched non-diabetic subjects, 103 (24) (p = 0.0000). Kidney size (cm2) was larger in diabetic subjects at follow-up, 114 (19) than at baseline, 109 (18) (p = 0.0000) and in non-diabetic subjects 98 (14) (p < 0.0000). This resulted in a decline in glomerular filtration rate per unit renal area in the diabetic subjects at follow-up, 1.0 (0.23) compared to at baseline, 1.09 (0.23) (p = 0.002) and to non-diabetic subjects, 1.07 (0.23). The renal area at baseline was directly and significantly related to the glomerular filtration rate at follow-up (p < 0.001). The relation of baseline serum cholesterol, hemoglobin A 1c and mean arterial blood pressure to the glomerular filtration rate at follow-up was inverse and reached significance in those diabetic subjects having had high filtration rates at baseline but displaying a faster decline than on average i.e. in those patients who were at increased risk of renal insufficiency. We conclude that after the first six years of non-insulin-dependent diabetes the glomerular filtration rate remains high. Kidney size increases further from the attained increase at diagnosis and is an important determinant of continuing hyperfiltration. The deleterious effect of serum cholesterol and high blood glucose on the glomerular filtration rate at this early stage of diabetic kidney disease is suggestive.

Fatty acid exercise scintigraphy after percutaneous transluminal coronary angioplasty

We performed a sequential fatty acid exercise-rest scintigraphy in 18 patients with an initially successful percutaneous transluminal coronary angioplasty (PTCA) to study the concordance of trends in symptoms, exercise tolerance and myocardial metabolism. Eleven patients stopped the exercise because of angina pectoris in the preoperative test; 2 days after PTCA this number decreased to two, but again increased to eight 3 months later. Exercise time (9.7 +/- 0.6 min, mean +/- SEM) and maximum exercise heart rate (128 +/- 4 beats min-1) were at least as good immediately after the operation as originally (8.8 +/- 0.6 min and 121 +/- 4 beats min-1, respectively). After 3 months both parameters were significantly (P < 0.05) better (10.3 +/- 0.6 min and 136 +/- 4 beats min-1, respectively) than originally. Some relative improvement in washout was noticed in 61% 2 days and in 56% of cases 3 months after PTCA. Fatty acid exercise uptake was more homogeneous in 72% of cases immediately after angioplasty and in 44% 3 months later. The trend in fatty acid uptake, exercise characteristics, and also in symptoms was most favourable among the eight patients with a dilatated left anterior descending coronary artery. Although the gamma camera technique possibly underestimated the effects of angioplasty, the impaired fatty acid metabolism could be linked with persistent symptoms after the operation. We conclude that most patients can safely participate in a symptom-limited (maximal) ergometry test already 2 days after PTCA, and that postoperatively myocardial perfusion and metabolism improve rapidly. However, this advantage is eventually lost to some degree, even if exercise tolerance continues to improve.

False inferoposterior fatty acid uptake rest defects in patients with first anterior myocardial infarction

Fatty acid scintigraphy is an interesting new technique for assessing the extent of myocardial infarction. We studied 19 patients with electrocardiographically verified first anterior myocardial infarction using radioiodinated phenylpentadecanoic acid and single photon emission computed tomography (SPECT). Besides the expected lesions in the territory of the left ascending coronary artery, a total of nine patients (47%) had severe (uptake < 50% of maximum) defects in the presumptive territory of the right coronary artery at rest. A link between the size of anterior injury and the occurrence of inferoposterior lesions was established. Over 20% paradoxical relative filling-in was seen in four of these inferoposterior defects in the subsequent exercise imaging, but only once anteriorly. Exercise-induced ischaemia (reduction in relative uptake > 20%) was demonstrated in 11 cases (58%). Ischaemia occurred most frequently in patients with small infarcts, and it did not coincide with the reversed redistribution. We conclude that the inferoposterior rest defects are unlikely to have been caused by technical artefacts or local injury, and should perhaps rather be linked with general strain in the left ventricle during the early phase of myocardial remodeling after anterior infarction. In any case, our results indicate that shortly after infarction myocardial viability should be evaluated very cautiously.

Short-term variability of blood pressure and heart rate in borderline and mildly hypertensive subjects

Electrocardiogram and intra-arterial blood pressure were recorded in 96 men (aged 35 to 45 years) by the Oxford method over a 30-hour period. The study involved 33 normotensive, 29 borderline hypertensive, and 34 mildly hypertensive individuals, as assessed by the cuff method. Five-minute periods during sleep and with subjects in supine, sitting, and standing positions were extracted from the recordings for frequency domain analysis. Power spectrum density estimates of systolic blood pressure, diastolic blood pressure, and heart rate were calculated by an autoregressive method over the bandwidths of 0.02 to 0.075 (low-frequency), 0.075 to 0.15 (midfrequency), and 0.15 to 0.35 Hz (high-frequency), attributable to thermoregulatory, baroreceptor, and respiratory activity. No significant intergroup differences were observed at nighttime, but in different body positions the borderline hypertensive subjects frequently had either greater low-frequency variability or smaller midfrequency variability than the other groups. In this respect, the power spectra for systolic and diastolic blood pressures provided better statistical differentiation between the groups than those for heart rate. Furthermore, the borderline hypertensive subjects exhibited attenuated night-day changes in the low-frequency band for all time series. The results suggest that in borderline hypertension the baroreceptor oscillations are shifted to lower frequencies, presumably reflecting altered function of the sympathetic nervous system. In conclusion, spectral analysis of blood pressure variability for controlled test situations made it possible to detect differences in the cardiovascular regulatory systems between normotensive, borderline hypertensive, and mildly hypertensive individuals.

Performance characteristics of various exercise ECG classifiers in different clinical populations

To improve the diagnostic power of the exercise electrocardiographic test in detecting myocardial ischemia, the authors have recently developed a diagnostic method called multivariate ST-segment/heart rate (ST/HR) analysis (MUSTA). The goal of this study was to evaluate the validity of MUSTA in different clinical populations and to compare its performance characteristics with ST-segment depression, the ST/HR slope, and the delta ST/HR index in these populations. The computerized exercise electrocardiographic measurements were performed on 1,507 cases, and 382 patients were selected as the study population: 161 with significant coronary artery disease according to coronary angiography and 221 with a low likelihood of coronary artery disease. The diagnostic accuracy of MUSTA in the pooled population was 77.7% (297 out of 382 patients), which was clearly better than the accuracy of 69.6% (266 out of 382 patients) using the conventional ST-segment depression criterion of 0.10 mV in detecting coronary artery disease and exercise-induced myocardial ischemia. According to receiver operating characteristics analysis, MUSTA had significantly better diagnostic power than the other classifiers. These findings suggest that multivariate and compartmental analysis methods like MUSTA can further improve the clinical importance of the exercise electrocardiogram.

Inferior epigastric artery as a conduit for myocardial revascularization

In 18 patients the inferior epigastric artery (IEA) was used for myocardial revascularization along with the left internal mammary artery and saphenous vein (4.5 grafts/patient). Preoperative duplex scan assessment of IEA correctly predicted its distal diameter. At operation the mean internal diameter was 1.6 (1.5-2.0) mm distally and 2.1 (2.0-2.5) mm proximally. The mean in situ flow after intraluminal injection of papaverine was 115 (36-210) ml/min in IEA and 136 (56-210) ml/min in internal mammary artery. There was no perioperative death or myocardial infarction. Morbidity associated with IEA harvesting was minor: ultrasonography showed diastasis and slower contraction of the rectus muscle at the harvesting site than contralaterally in one case. The preoperative duplex scan was useful for evaluating IEA size. All the patients were clinically improved. The patency rate at selective IEA angiography 3 months post-operatively was 72% (13/18). This poor early patency of IEA in our small series raises doubts concerning the vessel's suitability for myocardial revascularization.