[Analgesics are not available in ambulances].
Explore the source record for details and available documents.
Accidents, Traffic↗
Biomedical subjects
H Aström
Publications and source records attributed to H Aström.
Muscle characteristics in effort angina before and after CABG.
Seven males with effort angina undertook graded ergometer tests and had muscle biopsies taken from their vastus lateralis muscle before, and three and six months after coronary bypass surgery. Muscle fibre composition (percentage of slow twitch fibres), ubiquinone (vitamin Q), and oxidative and fermentative enzyme activities were determined. After six months, muscle ubiquinone and oxidative enzymes were still depressed, indicating sustained muscle trauma. The only peripheral changes were that muscle lactate dehydrogenase and its skeletal muscle-specific subunits and isozymes were increased 35% to 40% (P < 0.001) three to six months postsurgery. Onset of blood lactate accumulation (2.0 mmol/L), symptom-limited ('maximal') exercise and peak blood lactate increased linearly over time (r = 0.52, P < 0.05; r = 0.63, P < 0.01; and r = 0.76, P < 0.001, respectively). It is suggested that the initial physical performance increase was due to improved circulatory capacity, oxygen delivery and lactate efflux, whereas the increased fermentative capacity ('anaerobic power') first contributed after a lag of three or more months. Whether the muscle histochemical changes reflected a healing process (recovery) is speculative.
Angina Pectoris↗
Muscle ubiquinone in male effort angina patients.
Seven (7) males with effort angina and listed for coronary by-pass surgery had muscle biopsies taken from their vastus lateralis muscle for determination of muscle fiber types (%ST), ubiquinone (vitamin Q, UQ), oxidative and fermentative enzyme activities. Graded cycle ergometer exercise to determine intensities corresponding to onset of blood lactate accumulation set to 2.0 mmol x l-1 (WOBLA) and symptom limited exercise ('maximal', WSL) were also undertaken. WOBLA was positively related to %ST (r = 0.92, p < 0.001). %ST was on the other hand inversely related to UQ (r = -0.82, p < 0.05), the heart specific LD subunit LD-H (r = -0.96, p < 0.001), the isozyme LD3 as the fraction of LD (%LD3) (r = -0.93, p < 0.01), and the CK isozyme CKMB as the fraction of CK (%CKMB) (r = -0.88, p < 0.05). It was suggested that muscle UQ depletion in the patients was related to molecular oxygen and free oxygen radical formation. The lack of antioxidants then caused a radical trauma specifically to the ST fiber and their mitochondria. This could be a cause and-effect explanation for the selective ST fiber downregulation in effort angina and heart failure in general.
Adult↗
Long-term recording of cardiac output via an implantable haemodynamic monitoring device.
Long-term monitoring of central haemodynamics with implanted monitoring systems might be valuable in managing heart failure patients. Such systems offer an opportunity for repeated 'semi-invasive' cardiac output determinations according to the Fick principle. Five patients, four with chronic heart failure and one with chronic pulmonary disease, underwent supine exercise testing during cardiac catheterization at 0, 2, 6 and 11 months after implantation of a right ventricular mixed venous oxygen saturation sensor connected to an implantable haemodynamic monitor. The monitor provided a continuous measure of oxygen saturation via a radio-telemetry link to a metabolic cart capable of measurement of breath-by-breath oxygen consumption. Cardiac output was computed using oxygen consumption, mixed venous oxygen saturation, arterial oxygen saturation by pulse oximetry and haemoglobin oxygen capacity. Biosensor-derived oxygen saturation compared to blood samples from the pulmonary artery showed an excellent correlation over time, r2 = 0.94 (implant), r2 = 0.91 (6-11 months). There was a strong correlation between semi-invasive-determined cardiac output using the biosensor and the invasive technique, which persisted over the entire follow-up period. Repeated semi-invasive cardiac output measurements using an implanted haemodynamic monitoring system in chronic heart failure patients is feasible and the data may be of value for optimizing therapy.
Adult↗
Sinus node recovery time assessment revisited: role of pharmacologic blockade of the autonomic nervous system.
Sinus node recovery time assessment is used to diagnose clinically significant sinus node dysfunction (SND) when Holter has failed to prove a relationship between sinus bradyarrhythmias and symptoms, but consensus has not been reached as to the value of including assessment after pharmacologic blockade of the autonomic nervous system. This issue was addressed in the present study performed on 52 patients with syncope or presyncope/dizziness (n = 48), sinus bradyarrhythmias (n = 45), or both (n = 41). Group 1 consisted of 13 patients with a proven relationship between symptoms and sinus bradyarrhythmias. Group 2 consisted of 39 patients with suspected SND. The protocol included three pacing periods at two pacing rates and was performed at baseline (n = 52), after single doses of atropine and propranolol (0.02 mg/kg and 0.1 mg/kg, respectively) (n = 41), and again after a second dose (n = 29). The sensitivity of prolonged recovery times was 77% in group 1. Among group 2 patients, 56% had prolonged recovery times at baseline (79% when including the results after the first dose of drugs). The second dose did not contribute diagnostic information, but it caused significant adverse reactions in 7 of 29 patients (P < 0.001). These 7 patients were all older than 60 years. Assessment of sinus node recovery time after pharmacologic blockade of the autonomic nervous system thus increases the sensitivity of the method in patients with suspected SND and normal baseline results. However, only 50% of the initially suggested doses of atropine and propranolol is sufficient and eliminates the risk for significant adverse reactions.
Adult↗
[Temperature-directed radiofrequency ablation. A new safer treatment of tachycardia].
Explore the source record for details and available documents.
Adult↗
Diagnostic value of programmed ventricular stimulation in patients with bifascicular block: a prospective study of patients with and without syncope.
OBJECTIVES: The aim of this study was to examine the inducibility of ventricular arrhythmias in patients with bifascicular block both with and without a history of syncope and to relate the findings to clinical events during follow-up. BACKGROUND: Patients with bifascicular block have an increased risk of sudden death that is not reduced by pacemaker treatment. This risk could be related to a high incidence of ventricular arrhythmias. METHOD: Programmed ventricular stimulation was performed in 101 patients with bifascicular block: 41 had a history of unexplained syncope, and 60 were asymptomatic. RESULTS: Programmed ventricular stimulation resulted in a sustained ventricular arrhythmia in 18 patients (18%), 8 in the syncope group and 10 in the nonsyncope group (p = NS). Three patients in each group had an inducible sustained monomorphic ventricular tachycardia. During a mean follow-up of 21 months, 10 patients experienced a clinical event defined as sudden death (n = 4), syncope (n = 5) or appropriate discharges from an implantable cardioverter-defibrillator (n = 1). Only one of these patients had an inducible ventricular arrhythmia at baseline. CONCLUSIONS: The inducibility of ventricular arrhythmias is high in patients with bifascicular block and of the same magnitude in patients with and without a history of syncope. Clinical events during follow-up were not predicted by programmed ventricular stimulation in either of the two groups. The finding of inducible ventricular arrhythmia in patients with bifascicular block should therefore be interpreted with caution.
Adolescent↗
Screening for sinus node dysfunction by analysis of short-term sinus cycle variations on the surface electrocardiogram.
A new noninvasive screening method for diagnosing sinus node dysfunction (SND) was evaluated. Sinus cycle variations from 1-minute electrocardiograms (ECG) were described by two variables: the variation range around the mean cycle length (percentage) and the maximal change between any two consecutive cycles (milliseconds). SND was diagnosed when both variables were increased. Part 1: Validation of this method against Holter and sinus node recovery time assessment in 69 patients with proven or possible sick sinus syndrome (SSS). Part 2: Application of the method to 60 patients with clinically significant cardiovascular and pulmonary disorders (group 3), but without any pretest suspicion of SND. Part 1: Sinus cycle variations and sinus node recovery times were abnormal in similar proportions, 55% and 63%, respectively. The sensitivities in proven SSS were 72% and 71%, respectively. Sinus node function was concordantly classified in 80% of 64 patients undergoing both tests. When sinus cycle variations were abnormal the probability of a prolonged recovery time was 89%. Part 2: Asymptomatic SND was found in 12% of patients in group 3. Thus, analysis of short-term beat-to-beat variations in the surface ECG has a sensitivity of approximately 70% and a specificity of 100% for diagnosing SND.
Adolescent↗
Coenzyme Q10 as an adjunctive in the treatment of chronic congestive heart failure. The Q10 Study Group.
Seventy-nine patients with stable chronic congestive heart failure were randomized into a double-blind, crossover placebo controlled study with 3-month treatment periods, where either 100 mg coenzyme Q10 (CoQ10) or placebo was added to conventional therapy. Mean patient age was 61 +/- 10 years, ejection fraction at rest was 22% +/- 10%, and maximal exercise tolerance was 91 +/- 30 W. The follow-up examinations included ejection fraction (primary objective), exercise test, and quality of life questions. Ejection fraction at rest, during a slight volume load, and during a submaximal supine exercise increased slightly compared with placebo: 24% +/- 12% versus 23% +/- 12% (NS), 25% +/- 13% versus 23% +/- 12% (P < .05), and 23% +/- 11% versus 22% +/- 11% (NS). Maximal exercise capacity increased from 94 +/- 31 W during the placebo period to 100 +/- 34 W during the CoQ10 period (P < .05). Total score for the quality of life assessment increased significantly from 107 +/- 23 during the placebo period to 113 +/- 22 during the CoQ10 period (P < .05). The results indicate that oral long-term treatment with 100 mg CoQ10 in patients with congestive heart failure only slightly improves maximal exercise capacity and the quality of life and that the clinical importance of this needs to be further evaluated.
Aged↗
Monitoring of pulmonary arterial diastolic pressure through a right ventricular pressure transducer.
Pulmonary arterial diastolic pressure is an important parameter for hemodynamic monitoring in congestive heart failure. It is traditionally obtained through a pulmonary arterial catheter. If it could be obtained from a sensor in the right ventricle, chronic monitoring would be possible without the use of a pulmonary arterial catheter. This study is based on the hypothesis that pulmonary valve opening and pulmonary arterial diastolic pressure occur at the time of maximum positive rate of pressure development (dP/dt) in the right ventricle, when the pressures should be equal. Thus, right ventricular pressure at the time of maximum dP/dt (PAD index) should be a reasonable estimate of pulmonary arterial diastolic pressure. Eight patients with heart failure were catheterized and exposed to hemodynamic stress. Right ventricular and pulmonary arterial pressures were simultaneously recorded from a Millar (Houston, TX) catheter with two pressure transducers. The distal transducer was positioned in the bifurcation of the pulmonary artery and the proximal transducer was placed in the right ventricle. Pulmonary arterial diastolic pressure and PAD index were stored beat by beat on a bed-side computer. Acceptable recordings were obtained in all patients. Recordings from the individual patients showed a good covariation between PAD index and pulmonary arterial pressure during different hemodynamic manuevers, except during infusion of dobutamine, when the correlation was not as good. Pulmonary arterial diastolic pressure may be estimated from a transducer in the right ventricle, thus eliminating the need for a permanent pulmonary arterial catheter in an implantable hemodynamic monitoring system. Further studies are needed to verify the correlation on a long-term basis.
Aged↗
Monitoring of mixed venous oxygen saturation and pressure from biosensors in the right ventricle. A 24 hour study in patients with heart failure.
Right ventricle venous oxygen saturation was studied in 10 heart failure patients over 24 h using a lead equipped with an oxygen biosensor inserted temporarily. At the same time a pressure sensor, incorporated in the same lead to measure right ventricular pulse pressure and maximum positive and negative rate of pressure development (RV dP/dt), was tested to see whether it would interfere with the oxygen sensor. Data from the biosensor lead were continuously compared with mixed venous oxygen saturation obtained from a fibreoptic Swan-Ganz catheter with the tip in the pulmonary artery. For reference, blood samples were drawn at regular intervals from this catheter. A provocative protocol was used to cause haemodynamic changes. There was good correlation between oxygen saturation in the right ventricle (biosensor-derived) and mixed venous oxygen saturation in the pulmonary artery (fibreoptic-derived) (r = 0.86) and between sensor-obtained right ventricular oxygen saturation and oxygen saturation in the blood samples from the pulmonary artery (r = 0.90). Changes in central haemodynamics were also well reflected by changes in pulse pressure and dP/dt derived from the pressure sensor. As it was not possible to obtain absolute pressures no attempt was made to compare the pressure changes with conventional haemodynamics. These 24 h haemodynamic measurements suggest that a biosensor-equipped lead placed in the right ventricle could be a valuable tool for long-term monitoring of mixed venous oxygen saturation and pressure in patients with congestive heart failure.
Aged↗
Heart muscle ubiquinone and plasma antioxidants following cardiac transplantation.
Nine patients who underwent heart transplantation (one female; average age 48 +/- 11, range 19-58 years) were followed in respect to contents of right-sided heart septum, blood and plasma ubiquinone (UQ), plasma alpha-tocopherol (alpha T), and plasma free cholesterol (FC). In contrast to healthy persons, substantial inter- and intraindividual variations were observed; individually low values were seen with rejection. Heart muscle UQ in well-treated patients averaged 0.33 +/- 0.08, range 0.06-0.58 micrograms mg-1 (0.38 +/- 0.09 mumol g-1 dry weight) and was not different from healthy individuals. Plasma UQ, alpha T; and FC averaged 0.63 +/- 0.33 micrograms ml-1 (P < 0.05 versus sedentary controls), 8.1 +/- 4.0 micrograms ml-1 (P < 0.01), and 0.52 +/- 0.23 mg ml-1 (P < 0.05). Corresponding molar values were 0.73 +/- 0.37 (UQ), 2.0 +/- 1.1 mumol l-1 (alpha T), and 1.42 +/- 0.54 mmol l-1 (FC). Blood and plasma UQ values were identical. A saturation like relationship was found between heart and blood UQ:blood contents below 0.7 micrograms ml-1 (0.8 mumol l-1) corresponded to markedly lowered heart contents. In four patients in whom blood samples were taken close to a fatal complication it averaged 0.42 micrograms ml-1 (0.49 mumol l-1, P < 0.01). When low heart muscle and blood ubiquinone were present, other variables such as left ventricle cardiac output or cycle ergometer performance was markedly impaired. Plasma UQ and alpha T covaried with a marker of the lipoidal deposit volume, plasma FC.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Improved accuracy of indirect blood pressure measurement in patients with obese arms.
We studied 20 patients with moderate to severe obesity (body mass index 37 +/- 8 kg/m2) with obese arms (arm circumference 37 +/- 4 cm). Their blood pressure was measured directly in the brachial artery in one arm and simultaneously indirectly in the other arm using either a large standard cuff (rubber bag 12 x 35 cm) or a new cuff (the Tricuff, Pressure Group AB, Stockholm) containing three rubber bags of different sizes, which automatically selected the appropriately sized bag in relation to arm circumference. Both cuffs showed a significant overestimation of the diastolic blood pressure (standard cuff 13 mm Hg, P < .001, Tricuff 6 mm Hg, P < .01). The error of the standard cuff was significantly greater than that of the Tricuff (P < .001). The differences in systolic blood pressure between the intraarterially and the indirectly measured results were small (0.2 to 3 mm Hg) and not statistically significant with either cuff. The new Tricuff offered an advantage as compared to a large standard cuff in terms of a lesser overestimation of the diastolic blood pressure. In practical terms, this should lead to a reduction in the overestimation of diastolic hypertension in obese individuals.
Adult↗
Factors affecting the validity of the standard blood pressure cuff.
Fifty-eight patients, 31 women and 27 men, with a wide range of upper arm circumferences (20-43 cm), ages (16-82 years) and body mass indices (16-55 kg m-2) were studied. The direct blood pressure was measured in the brachial artery in one arm and simultaneously the indirect pressure was measured in the other arm using a large standard cuff (rubber bag 12 x 35 cm). The mean intra-arterial blood pressure was (systolic/diastolic) 137 +/- 25 mmHg (SD)/76 +/- 10 mmHg. With the cuff the mean blood pressure was 134 +/- 23 mmHg/85 +/- 11 mmHg. The cuff significantly underestimated the systolic blood pressure (3.2 +/- 11.4 mmHg, range -25-30 mmHg) while the diastolic pressure was overestimated significantly (8.8 +/- 8.5 mmHg, range -32-14 mmHg). The direct/indirect blood pressure difference correlated significantly to the intra-arterial systolic and diastolic pressures (systolic/diastolic; r = 0.44, P = 0.0006/r = 0.36, P = 0.0062), but only to the auscultatory diastolic pressure (r = -0.02, P = 0.9/r = -0.45, P = 0.0004). The direct/indirect difference correlated significantly to the arm circumference (r = -0.33, P = 0.01/r = -0.30, P = 0.02) as did the diastolic direct/indirect difference to pulse rate (r = 0.34, P = 0.009). Age did not correlate significantly to the direct/indirect blood pressure difference in this study (r = -0.02, P = 0.9/r = -0.10, P = 0.5). It can be concluded that in addition to the ratio between the arm circumference and the width of the cuff (rubber bag), there are other sources of systematic errors of indirect blood pressure measurement, in particular pulse rate and the level of indirect blood pressure. If corrections could be made with regard to these variables, it is obvious that the reliability of the indirect method, especially when used in epidemiological contexts, would increase.
Adolescent↗
[Radiofrequency ablation--promising treatment in supraventricular arrhythmia].
Explore the source record for details and available documents.
Adult↗
Ischaemic heart disease, skeletal muscle fibres and exercise capacity.
Twenty-eight male patients with ischaemic heart disease (IHD) performed OBLA (onset of blood lactate accumulation) exercise stress tests and had muscle biopsies taken from their vastus lateralis muscle the day before coronary bypass grafting. All 28 patients showed the same exercise performance pattern as compared to healthy sedentary, age-matched, controls: a low exercise intensity eliciting a blood lactate concentration of 2.0 mmol x l-1 (WOBLA), WOBLA corresponded to a high fraction (% WOBLA) of WSL (symptom limited or 'maximal' capacity), and a low peak blood lactate concentration. The high % WOBLA and low peak blood lactate indicated a reduced glycogenolytic capacity ('anaerobic' performance). Muscle fibre composition disclosed a high mean value of fast twitch (FT), type II or 'white' muscle fibres, as compared to sedentary healthy controls. This indicated that this patient group constituted an extreme subgroup of the age-matched population. The distorted muscle fibre composition in IHD could reflect both heredity as well as adaptation to physical inactivity, degenerative cytosolic properties, etc. Muscle and blood contents of a mitochondrial electron translocator and nonspecific radical scavenger, ubiquinone or coenzyme Q10(CoQ10), were low, which coincided with an elevated frequency of the fibre subgroup FT(c). The presence of the FT(c) fibre type is assumed to reflect histological trauma.
Adult↗
Is blood pressure measurement with a standard cuff reliable?
This study compares blood pressures measured with a standard cuff (rubber bag 12 x 35 cm) with concomitantly measured intra-arterial pressures in 48 subjects. With the standard cuff, and using a diagnostic cut-off limit for diastolic hypertension of 90 mmHg, 15/48 patients were found to be hypertensive, whereas only 4/48 had intraarterial pressure above 90 mmHg. Thus, the specificity of the non-invasive method was only 75%. If higher diagnostic cut-off limits were used, e.g. 95 mmHg, specificity increased to 84%, and with lower cut-offs specificity was 63% for 85 mmHg and 52% for 80 mmHg. A specificity of only 75% is very poor for a method commonly used in screening examinations and may lead to considerable over-diagnosis of mild hypertension.
Adolescent↗