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Biomedical subjects

Ivar Ringqvist

Publications and source records attributed to Ivar Ringqvist.

14 recordsLinked to original sources
PubMed2007

Echocardiographic Doppler assessments of left ventricular filling and ejection during upright exercise in endurance athletes.

Doppler echocardiography was used to describe left ventricular filling and ejection during upright bicycle exercise in 24 healthy male endurance athletes. The transmitral pressure gradient was estimated and isovolumetric relaxation, filling and ejection time and transmitral and aortic flow velocities were measured at rest and during exercise. From rest to peak exercise (at a heart rate of 160 bpm), the mean left ventricular filling time was shortened by 73%, the ejection time by 31%, while the isovolumetric relaxation time was shortened by 62%. At peak exercise, the maximum aortic flow velocity almost doubled and the maximum transmitral flow velocity more than doubled, with a tenfold increase in the mean transmitral pressure gradient. The increase was significant (P<0.001) at each level of exercise. The left ventricular filling rate measured as volume per time was 185 +/- 62 ml s(-1) at rest and it increased to 986 +/- 192 ml s(-1) at peak exercise. This study demonstrates large changes in diastolic filling indices during upright exercise and it shows that the heart is able to increase its filling rate five times from rest to peak exercise.

Adult↗
PubMed2006

Mitral annulus motion as a predictor of mortality in a community-based sample of 75-year-old men and women.

Mitral annulus motion (MAM) is a predictor of mortality in selected patient groups, but its prognostic value in less selected populations is not known. In a community-based random sample of 75-year-old men and women (n = 408), left ventricular function was measured as: (1) maximum amplitude of MAM; and (2) wall-motion index. During a median follow-up of 7.2 years, 83 persons died (26 from cardiac causes). Left ventricular function as measured by MAM predicted the risk of all-cause and cardiac mortality independently of other potential risk factors in this community-based sample. Regarding cardiac mortality, the predictive ability of MAM was also independent of left ventricular systolic function measured as wall-motion index. MAM may prove to be a valuable complement to other echocardiographic methods in the assessment of prognosis in less selected populations.

Aged↗
PubMed2006

Two different training programmes for patients with COPD: a randomised study with 1-year follow-up.

PURPOSE: To compare the effects on exercise capacity and health related quality of life (HRQoL) of two exercise programmes; one programme including endurance training and one including only resistance training and callisthenics. A second purpose was to find out whether the severity of chronic obstructive pulmonary disease (COPD) affected the training response and whether the interventions had a long-term effect. METHODS: Sixty-three patients were stratified according to severity of COPD and randomised to two training groups. Group A had a mixed programme including endurance training. Group B had resistance training and callisthenics. All trained twice weekly for 8 weeks. A symptom-limited ergometer test, 12-min walking test, dynamic spirometry, blood gas analysis at rest and HRQoL were measured before and after the training period. Follow-up tests were conducted at 6 and 12 months after training. RESULTS: Forty-two patients fulfilled the trial. In group A (n=20) peak exercise capacity increased by 7W (P<0.001) and 12-min walking distance (12MWD) by 50 m (P<0.01), whereas group B (n=22) did not change in any of these variables. HRQoL did not change significantly in either group. Training response was similar in patients with moderate and severe disease. One year post-training 12MWD had returned to pre-training level in group A, and below pre-training level in group B (P<0.05). CONCLUSIONS: Exercise capacity in patients with severe and moderate COPD improved by intensive endurance training, two sessions a week for 8 weeks. The improvement was however small and HRQoL did not improve. Severity of illness did not affect response to training. The results indicated that the effects of a short endurance training intervention slowed down decline in baseline functional exercise capacity for 1 year.

Aged↗
PubMed2005

Social background, aspects of lifestyle, body image, relations, school situation, and somatic and psychological symptoms in obese and overweight 15-year-old boys in a county in Sweden.

OBJECTIVE: To compare lifestyle and health aspects among obese, overweight, and normal-weight 15-year-old boys living in the county of Västmanland, Sweden. DESIGN: A cross-sectional school-based survey. Setting. All schools in the county of Västmanland, Sweden. SUBJECTS: A questionnaire was completed anonymously by 989 boys. MAIN OUTCOME MEASURES: The relations between body mass index and social factors, eating habits, physical activity, body image, relations, school situation, use of alcohol, drugs and tobacco, somatic and psychological symptoms in boys. RESULTS: Obese boys had a significant negative outcome in 19 out of 31 items studied compared with normal-weight boys, while the overweight boys had a significant negative outcome in 9 out of 31. The obese boys reported more irregular eating habits than normal-weight boys, were less satisfied with their weight and looks, and had fewer friends. A larger proportion of the obese boys reported that they did not like school, were more absent from school, and had been exposed to more violence. They bullied their schoolmates more often. The obese boys had tried sniffing solvents and used illicit drugs more frequently than their peers. They reported more somatic and psychological symptoms as well as suicidal thoughts and attempts. CONCLUSIONS: Obese 15-year-old boys differed from overweight and normal-weight boys in lifestyle and in the frequency of somatic and psychological symptoms. Early and vigorous intervention is necessary, as they may belong to a risk group that could develop not only medically but also socially negative consequences.

Adolescent↗
PubMed2004

Electrocardiogram and B-type natriuretic peptide as screening tools for left ventricular systolic dysfunction in a population-based sample of 75-year-old men and women.

BACKGROUND: Plasma concentration of B-type natriuretic peptide (BNP) has been suggested as a powerful screening tool for left ventricular systolic dysfunction. However, there are reports indicating that the 12-lead electrocardiogram (ECG) could be just as powerful. We aimed to evaluate the 12-lead ECG and BNP as screening tools for left ventricular systolic dysfunction in an elderly, unselected population. METHODS: In a randomly selected population-based sample of 75-year-old men and women (n = 407), diagnostic characteristics were evaluated for the ECG and plasma concentration of BNP to detect left ventricular systolic dysfunction. RESULTS: Sensitivity, specificity, and negative and positive predictive values for the ECG to detect left ventricular systolic dysfunction were 96%, 79%, 100%, and 26%, respectively. The corresponding values for the BNP (cut-off value 28 pg/mL) were 93%, 55%, 99%, and 13%. In participants without major abnormalities in the ECG, left ventricular systolic dysfunction was found in <1% (1/302), irrespective of BNP concentrations. In participants with abnormal ECGs, systolic dysfunction was more prevalent in persons with abnormal BNP concentrations than in those with normal concentrations (35% vs 3%, difference 32%, 95%CI for the difference 16%-44%) CONCLUSIONS: In 75-year-old subjects both the ECG and the plasma concentration of BNP are highly efficient in excluding left ventricular systolic dysfunction. However, compared with the BNP, the ECG yields a lower number of false positive cases. In screening for left ventricular systolic dysfunction, the BNP has a diagnostic value in addition to the ECG, but only in individuals with abnormal ECGs.

Aged↗
PubMed2004

Accuracy of spectral Doppler flow and tissue velocity measurements in ultrasound systems.

Blood and tissue velocity are measured and analysed in cardiac, vascular and other applications of diagnostic ultrasound (US). An error in system calibration is a potential risk for misinterpretation of the measurements. To determine the accuracy in velocity calibration, we tested three common commercial US systems using a Doppler string phantom. We tested pulsed and continuous-wave Doppler modes for velocities relevant to both cardiac blood flow and tissue-velocity estimation. The US systems were tested with settings and transducers commonly used in cardiac applications. One system consistently overestimated velocity by about 5%, whereas the other two systems were quite accurate in velocity estimation. These findings emphasize the importance of continuous quality control of US equipment.

Blood Flow Velocity↗
PubMed2003

A prospective randomized study comparing two different degrees of mandibular advancement with a dental appliance in treatment of severe obstructive sleep apnea.

The objective of this study was to compare the effect of two different degrees of mandibular advancement (MA), 75% versus 50%, on somnographic variables after 6 months of dental appliance treatment in patients with severe obstructive sleep apnea (OSA). A further purpose was to compare the number of adverse events on the stomatognathic system and the effects of dental appliance treatment on the presence of daytime sleepiness. Eighty-six males with severe OSA (apnea index > or = 20) were randomly allocated to either 75% or 50% MA. Forty patients in the 75% MA group and 37 patients in the 50% MA group completed the 6-month follow-up. The effectiveness of treatment in terms of normalization (apnea index < 5 and apnea/hypopnea index < 10) with 75% MA was 52%, which was significantly higher (p = 0.04) than the 31% achieved with 50% MA. The dental appliance had few adverse events on the stomatognathic system regardless of group, and the number of adverse events did not differ between the two groups. Finally, the mean value of Epworth Sleepiness Scale scores decreased significantly from 11.6 at baseline to 8.0 at follow-up (p < 0.001). No significant difference was observed between the two groups. The results indicate that a dental appliance could be an alternative treatment for some patients with severe OSA.

Adult↗
PubMed2003

Dental and skeletal changes after 4 years of obstructive sleep apnea treatment with a mandibular advancement device: a prospective, randomized study.

The aim of this prospective, randomized study was to analyze dental and skeletal side effects after 4 years of treating obstructive sleep apnea (OSA) patients with a mandibular advancement device (MAD) compared with uvulopalatopharyngoplasty (UPPP). With the appliance in position, the mandible was advanced 50% of maximum protrusion capacity (ie, 4-6 mm); the vertical opening between the incisal edges was, on average, 3 mm. Thirty patients in the MAD group and 37 in the UPPP group completed the 4-year follow-up. There were no differences between the MAD and the UPPP groups in any of the dental or skeletal variables measured after the 4-year treatment period. In the MAD group, small but statistically significant changes were found: there was a posterior rotation of the mandible (mandibular line [ML]/nasion-sella line [NSL]) (mean 0.5 degrees [95% confidence interval (CI) 0.1-0.8 degrees ]). Correlated to the posterior rotation of the mandible, the distances incision superius ML, incision superius-NSL, and incision inferius-NSL increased by means (95% CI) of 0.7 (0.5-1.2), 0.8 (0.4-1.1), and 1.3 (0.8-1.8) mm, respectively. Overjet and overbite did not change significantly, nor was there a significant change in the mandibular length. The observed changes were considered clinically insignificant because overbite and overjet stayed within normal limits. Only the vertical position of the maxillary incisors in relation to ML changed to the extent that the 95% CI of the mean for the change was outside that of the mean of the change in the UPPP group and measurement error. Treatment of OSA with a dental appliance is probably a lifelong process, and long-term follow-up studies should therefore be undertaken to control both the treatment effect on OSA and the side effects on the masticatory system.

Cephalometry↗
PubMed2003

Mitral annulus motion compared with wall motion scoring index in the assessment of left ventricular ejection fraction.

The biplane disc summation method is the recommended echocardiographic procedure to determine left ventricular (LV) ejection fraction (EF). Assessment of mitral annulus motion (MAM) or wall motion scoring index (WMI) has been reported to be less dependent on image quality compared with the recommended method, and proposed as a surrogate to the disc summation method in calculation of LVEF. We aimed to compare MAM and WMI in the echocardiographic assessment of LVEF. In a randomly selected population-based sample of 75-year-old men and women in sinus rhythm (n = 409) MAM, as measured by M-mode, was compared with WMI, calculated as the mean value of wall motion scoring in 9 LV segments. LVEF, as measured by the biplane disc summation method was used as reference. The limits of agreement (mean difference +/- 1.96 SD) between LVEF and corresponding MAM values were -18 to +13 LVEF%, and between LVEF and corresponding WMI values were -12 to +13 LVEF%. The areas under the receiver operating characteristic curves for MAM and WMI to predict a LVEF < 50% were 0.892 and 0.998, respectively (95% confidence interval of the difference 0.062-0.149). The corresponding areas for MAM and WMI to predict a LVEF < 40% were 0.955 and 0.998, respectively (95% confidence interval of the difference 0.017-0.069). In conclusion, the ability of WMI to estimate LVEF was more favorable than MAM in this population-based sample of 75-year-old participants. The findings suggest that the WMI is preferable to MAM in estimating LVEF.

Aged↗
PubMed2003

Effect of right atrial overdrive pacing in the prevention of symptomatic paroxysmal atrial fibrillation: a multicenter randomized study, the PAF-PACE study.

The aim of this study was to assess if right atrial overdrive pacing can suppress symptomatic episodes of paroxysmal atrial fibrillation (PAF) in patients without bradyarrhythmias. Forty-two patients with frequent and symptomatic PAF without other pacing indication had a pacemaker implanted after a 4-week run-in period, during which the frequency of symptomatic PAF episodes and the mean heart rate were objectively documented. Depending on the mean heart rate recorded during run-in, the pacemaker was programmed in random order to right atrial AAI pacing at 10-19 beats/min > mean heart rate (medium overdrive [MO]), at 20-29 beats/min > mean heart rate (high overdrive [HO]) and to no pacing (OAO mode) for 4-12 weeks each using a crossover design. In the 35 patients who completed the protocol, the number of symptomatic episodes of PAF (>30-second duration) per week was significantly lower during MO pacing (median 0.88, P = 0.001, n = 35) and during HO pacing (median 0.75, P = 0.002, n = 20) than during OAO (median 2.02 and 2.04, respectively). There was no difference between MO and HO pacing in the 20 patients paced at both rates (0.97 vs 0.75, P = 0.33). Seven patients did not complete the protocol due to persistent atrial fibrillation (n = 4), angina pectoris requiring surgery (n = 1), and unwillingness to continue the study due to improvement (n = 1) or worsening (n = 1) of symptoms during the study periods. Right atrial overdrive pacing can reduce the number of symptomatic PAF episodes in patients with frequent and drug refractory PAF but without bradyarrhythmias.

Anti-Arrhythmia Agents↗
PubMed2002

Time delays in ultrasound systems can result in fallacious measurements.

Even short time delays (less than 30 ms) in cardiac motion pattern may have clinical relevance. These delays can be measured with echocardiography, using techniques such as flow and tissue Doppler and M-mode together with external signals (e.g., ECG and phonocardiography). If one or more of these signals are delayed in relation to the other signals (asynchronous), an incorrect definition of cardiac time intervals can occur, the consequence of which is invalid measurement. To determine if this time delay in signal processing is a problem, we tested three common ultrasound (US) systems using the ECG as the reference signal. We used a digital ECG simulator and a Doppler string phantom to obtain test signals for flow and tissue pulsed Doppler, M-mode, phonocardiography, auxiliary and ECG signals. We found long time delays of up to 90 ms in one system, whereas delays were mostly short in the two other systems. The time delays varied relative to system settings. Consequently, to avoid these errors, precise knowledge of the characteristics of the system being used is essential.

Blood Flow Velocity↗
PubMed2002

4-year follow-up of treatment with dental appliance or uvulopalatopharyngoplasty in patients with obstructive sleep apnea: a randomized study.

STUDY OBJECTIVES: To evaluate the effects of treatment with a dental appliance or uvulopalatopharyngoplasty (UPPP) on somnographic variables in patients with mild-to-moderate obstructive sleep apnea (OSA) followed up for 4 years, and compliance and complementary treatment. DESIGN: Randomized study. SETTING: Central Hospital, Västerås, Uppsala University, Sweden. PATIENTS: Ninety-five male patients with confirmed mild-to-moderate OSA (apnea index [AI] > 5 and < 25) were randomized to treatment with a dental appliance or UPPP. Sleep studies were performed before and 1 year and 4 years after intervention. Thirty-two patients in the dental-appliance group and 40 patients in the UPPP group completed the 4-year follow-up. RESULTS: The success rate (percentage of patients with at least 50% reduction in AI) in the dental-appliance group was 81%, which was significantly higher than in the UPPP group, 53% (p < 0.05). Normalization (AI < 5 or apnea/hypopnea index < 10) was observed in 63% of the dental-appliance group and 33% of the UPPP group after 4 years. The difference between the groups was significant (p < 0.05). The compliance to use of the dental appliance was 62% at the 4-year follow-up. Thirty patients (75%) in the UPPP group continued without complementary treatment. The dental appliances had few adverse effects on the stomatognathic system, and the number of adjustments and repairs of the appliances over time was moderate. Pronounced complaints of nasopharyngeal regurgitation of fluid and difficulty with swallowing after UPPP were reported by 8% and 10%, respectively. CONCLUSIONS: The dental-appliance group showed significantly higher success and normalization rates regarding the somnographic variables compared to the UPPP group, but the effectiveness of the dental appliance was partly invalidated by the compliance of 62% at the 4-year follow-up. However, the appliances had few adverse effects on the stomatognathic system and required only moderate adjustments. Use of a dental appliance with regular follow-up can be recommended for long-term treatment of OSA.

Follow-Up Studies↗
PubMed1999

Factors of Importance to Doppler Indexes of Left Ventricular Filling in 50-Year-Old Hypertensive Persons.

Altered left ventricular (LV) diastolic filling has been shown in subjects with hypertension. Age is a major determinant of Doppler indexes of LV diastolic filling; therefore, a group of subjects of uniform age should preferably be chosen, if other determinants of diastolic LV filling are to be studied. A limited body of data is available regarding Doppler indexes of LV filling in hypertensive persons of a similar age. We therefore evaluated 26 hypertensive subjects (13 women and 13 men) 50 years old by Doppler echocardiography. The peak velocity of early diastolic filling (E wave), the peak velocity of atrial filling (A wave), the early-to-atrial peak velocity (E/A) ratio, and the deceleration time of early velocity were measured. The peak E wave velocity was 0.76 +/- 0.11 versus 0.62 +/- 0.13 m/s (P < 0.005), and the E/A ratio was 1.11 +/- 0.24 versus 0.93 +/- 0.23 (P < 0.05) in hypertensive women and men, respectively. The peak A wave velocity was increased and the E/A ratio was decreased in both hypertensive women and men compared with healthy 50-year-old subjects. In multivariate analyses, LV diameter, body mass index, and gender correlated with the E/A ratio in hypertensive persons. It is concluded that there is a significant difference in Doppler LV filling indexes between 50-year-old hypertensive women and men. LV diameter, gender, and body mass index are independent determinants of LV diastolic inflow in similarly aged hypertensive persons.

Journal Article↗