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Biomedical subjects

M Rosenqvist

Publications and source records attributed to M Rosenqvist.

At least 19 recordsLinked to original sources
PubMed1996

Quality of life in octogenarians after valve replacement due to aortic stenosis. A prospective comparison with younger patients.

BACKGROUND: Results of aortic valve surgery in octogenarians have been evaluated as event-free survival. However, little attention has been given to quality of life aspects. METHODS: Thirty-two consecutive patients, mean age 83 +/- 2 years, undergoing valve replacement due to aortic stenosis, were compared to 30 patients, mean age 71 +/- 3 years, undergoing the same procedure. Mortality, morbidity and quality of life were studied. An interview was performed before surgery and 3 and 12 months postoperatively. The questionnaire contained items related to self-rated health, symptoms, physical ability, sleep disturbances and social and emotional functioning. RESULTS: Pre-operatively the older patient group was in a worse condition with a higher NYHA functional class and a more pronounced cardiomegaly. They had more cardiac symptoms and were more depressed. The control group had a higher score for physical ability and rated their quality of life as better. Postoperatively there was a higher early mortality rate in the octogenarians (9% vs 0%; ns). After 3 months, improvement of functional status and relief of symptoms was observed in both groups. Physical ability improved and the depression score decreased significantly in both groups. Self-rated health and quality of life improved. One year after valve replacement the improvement in quality of life was of a similar magnitude in the two groups. CONCLUSION: Following aortic valve replacement, octogenarians, despite a more compromised pre-operative status showed an improvement in symptomatology, physical ability and general well being, of a similar magnitude to that of the younger patients group. These findings lend further support to the recommendation that valve replacement should be performed in octogenarians with symptomatic aortic stenosis.

Aged↗
PubMed1995

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↗
PubMed1995

Results of atrioventricular synchronous pacing with optimized delay in patients with severe congestive heart failure.

To verify that atrioventricular (AV) synchronous pacing (DDD) with short AV delay improves the condition of patients with severe congestive heart failure, we implanted DDD pacemakers in 10 patients with severe heart failure (New York Heart Association [NYHA] class III to IV). One day after pacemaker implantation, the AV delay was optimized by Doppler echocardiographic measurements over the aortic outflow tract. Patients were evaluated regarding NYHA class, stroke volume, cardiac output, ejection fraction, and quality of life at 1, 3, and 6 months after pacemaker implantation. Although the optimized AV delay was associated with short-term improvement in stroke volume and cardiac output (baseline stroke volume = 22 +/- 7 ml, day 1 = 28 +/- 12 ml; p = 0.03: baseline cardiac output = 1.9 +/- 0.6 L/min, day 1 = 2.2 +/- 1.1 L/min; p = 0.10), the mean stroke volume, cardiac output, NYHA class, and ejection fraction did not change significantly after 1, 3, and 6 months of pacing compared with baseline values. Three patients improved in NYHA class during the follow-up. A consistent improvement in stroke volume, cardiac output, NYHA class, and ejection fraction was observed in only 1 patient. In conclusion, we found no beneficial effects of AV-synchronous pacing with optimized AV delay in patients with severe heart failure.

Adult↗
PubMed1995

Cardiac release of histamine after ventricular fibrillation and defibrillation during insertion of implantable cardioverter defibrillators (ICD).

Histamine has inotropic, chronotropic, arrhythmogenic, and vasoactive effects, and is released from the heart in ischaemia-reperfusion injury. The effect of ventricular fibrillation (VF) and defibrillation (DEF) on histamine release was investigated in 9 anaesthetized patients undergoing transvenous implantation of ICD. Concomitant arterial and coronary sinus (CS) blood samples were drawn before induction of VF (duration 20 seconds), immediately after, and 2 and 5 min after DEF (18-24 Joules). Basal arterial histamine was 2.5 +/- 6 nmol/l, and did not increase after VF. The histamine level in CS was 1.1 +/- 0.2 nmol/l before VF (p < 0.008 compared to arterial), and increased to 2.5 +/- 0.6 nmol/l immediately after (p < 0.045 compared to basal), to 3 +/- 1.1 nmol/l 2 min after (p < 0.45), and to 2.4 +/- 0.8 nmol/l 5 min after VF. In the basal state there was an uptake of histamine across the coronary circulation. After VF/DEF the level of histamine increased in coronary venous blood, suggesting cardiac release of histamine.

Aged↗
PubMed1995

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↗
PubMed1995

Use of signal-averaged electrocardiography for predicting inducible sustained monomorphic ventricular tachycardia in patients with bundle branch block with and without a history of syncope.

The aim of this study was to examine the utility of signal-averaged electrocardiography in relation to inducible sustained monomorphic ventricular tachycardia in patients with bundle branch block. One hundred fourteen patients with bundle branch block underwent signal-averaged electrocardiography in the time domain and programmed ventricular stimulation. Sustained monomorphic ventricular tachycardia was induced in 17 patients. The mean values of the three signal-averaged electrocardiographic variables analyzed differed significantly between the inducible and the noninducible group. The filtered QRS duration showed the most prominent difference between the two groups, and a filtered QRS duration > or = 155 msec had a sensitivity of approximately 80%, a specificity of 60%, and a total predictive value of 65%. In the subgroup of patients with syncope, a combination of these criteria with a history of coronary artery disease had a sensitivity of 100% and a specificity of 90%.

Aged↗
PubMed1995

Cardiac outflow of endothelin, neuropeptide Y and noradrenaline in relation to hyperaemia in coronary sinus flow following electrical conversion of induced ventricular fibrillation in man.

The implanted cardioverter defibrillator represents an alternative therapy for patients with drug-refractory malignant ventricular arrhythmias. Implantation and testing of the device requires that ventricular fibrillation be evoked and converted, thus providing a situation in which cardiovascular haemodynamics can be studied. In this study we have evaluated the effects of electrically induced ventricular fibrillation, followed by defibrillation, on coronary sinus blood flow and cardiac outflow of endothelin- and neuropeptide Y-like immunoreactivity (-LI) and of noradrenaline. Twelve patients were studied during implantation of a defibrillator. Ventricular fibrillation was induced and terminated after 17 +/- 1 s 5 +/- 1 times in each patient. In six patients coronary sinus blood flow was measured continuously. Plasma samples were obtained from four of these patients and another six patients, from the coronary sinus, radial artery and central vein before and during fibrillation and at two time points ( < 30 s and 5 min). Basal coronary sinus blood flow decreased to 38% at 14 +/- 2 s of ventricular fibrillation. Immediately following defibrillation there was a short-lasting increase in coronary sinus blood flow to 244% and a significant increase in the levels of neuropeptide Y-LI (146%) and noradrenaline (158%) in the coronary sinus while endothelin-LI remained unchanged (97%). Neither fibrillation nor defibrillation evoked any changes in the peripheral arterial and venous levels of endothelin-, neuropeptide Y-LI or noradrenaline. It is concluded that coronary sinus blood flow is markedly reduced during fibrillation and that restoration of normal impulse activity is followed by short-lasting hyperaemia. There was no evidence for effects on the vascular endothelium as assessed by endothelin levels.

Adult↗
PubMed1995

Long-term follow-up of patients treated by radiofrequency ablation of the atrioventricular junction.

Radiofrequency ablation of the AV conduction tissue (His-bundle ablation) is an accepted treatment for therapy resistant atrial fibrillation/flutter. However, data on the long-term effects of the procedure are limited. We followed 50 patients for a mean of 17 months after AV junction ablation. The indication was treatment resistant atrial fibrillation or flutter. The patients underwent a standardized interview performed by two nurses. Health care was studied via the in-patient register. Subjective improvement was reported by 88% and the number of days in hospital per year was reduced from 17 to 7. The use of antiarrhythmic drugs was reduced by 75%. If the reduction in costs of drugs and days in hospital is compared with the cost of the ablation and the pacemaker implantation, breaking even is achieved after 2.6 years. We could not confirm that patients with paroxysmal atrial fibrillation note less improvement than those with chronic fibrillation. CONCLUSION: Ablation of the AV junction is a cost effective treatment with good long-term results and relatively few complications. RECOMMENDATIONS: Chronic atrial fibrillation: If sinus rhythm cannot be established and in cases in which heart rate regulating drugs have been ineffective, ablation of the AV junction with implantation of a VVIR pacemaker is recommended. PAROXYSMAL ATRIAL FIBRILLATION: If the patient despite treatment with antiarrhythmic drugs continues to have symptomatic episodes of atrial fibrillation, then AV junction ablation with implantation of a permanent pacemaker is recommended. Patients who have self-limiting episodes of atrial fibrillation should be given a DDDR pacemaker with an automatic mode switch. Patients who do not have self-limiting attacks and require DC conversion, should receive a VVIR pacemaker.

Adult↗
PubMed1995

Prospective study of left ventricular function after radiofrequency ablation of atrioventricular junction in patients with atrial fibrillation.

BACKGROUND: In patients with drug resistant incessant supraventricular tachycardia, radiofrequency induced ablation of the atrioventricular junction and pacemaker implantation have hitherto been considered a treatment of last resort. OBJECTIVE: To assess the short and long term effects of ablation of the atrioventricular junction on systolic and diastolic left ventricular function in patients with atrial fibrillation with and without impaired left ventricular function. PATIENTS: 29 patients (19 men; mean age 65 (SD 7) years (range 50-76)) undergoing ablation of the atrioventricular junction for drug refractory atrial fibrillation were examined a mean of 2, 65, and 216 days after ablation of the bundle of His. MAIN OUTCOME MEASURES: Left ventricular ejection fraction and early filling deceleration times (Edec) were assessed by Doppler echocardiography after 1 to 2 hours of ventricular pacing at a rate of 80 beats/minute. RESULTS: In 14 patients with a left ventricular ejection fraction < 50% left ventricular ejection fraction increased significantly from 32% (11%) to 39% (11%) (65 days) and 45% (11%) (216 days) (P < 0.001); Edec increased from 142 (46) ms to 169 (57) ms (65 days) and 167 (56) ms (216 days) (P < 0.05). In 15 patients with an ejection fraction > or = 50% at the initial examination no significant change in systolic function was observed. CONCLUSIONS: In patients with left ventricular dysfunction long term improvement of systolic and diastolic left ventricular function was seen after ablation of the atrioventricular junction for rate control of atrial fibrillation. This procedure had no adverse effects on normal left ventricular function.

Aged↗
PubMed1995

Disopyramide stress test: a sensitive and specific tool for predicting impending high degree atrioventricular block in patients with bifascicular block.

OBJECTIVE: To study the value of intravenous disopyramide as part of an invasive electrophysiological study in predicting impending high degree atrioventricular block in patients with bifascicular block. DESIGN: An invasive electrophysiological study was performed in the basal state and after the infusion of disopyramide (2 mg/kg body weight). The progression to high degree atrioventricular block was assessed by bradycardia-detecting pacemakers or repeated 12-lead electrocardiogram recordings, or both. PATIENTS: 73 patients with bifascicular block were included, of whom 25 had a history of unexplained syncope. The remaining 48 patients had no arrhythmia related symptoms and were included as controls. All patients had an ejection fraction of > 35%. RESULTS: After a mean follow up of 23 months, seven patients in the syncope group and three in the non-syncope group had a documented high degree atrioventricular block or pacemaker-detected bradycardia of < or = 30 beats/min for > or = 6 s. The sensitivity of the disopyramide test was 71% and the specificity 98%. The corresponding figures for an abnormal electrophysiological study in the basal state were 14% and 91%, respectively. CONCLUSIONS: The sensitivity of an invasive electrophysiological study in patients with bifascicular block and syncope can be markedly increased by the use of intravenous disopyramide. A positive test is a highly specific finding and warrants pacemaker implantation.

Adolescent↗
PubMed1994

Atrioventricular block progression in patients with bifascicular block assessed by repeated electrocardiography and a bradycardia-detecting pacemaker.

Syncope may be due to intermittent high-degree atrioventricular (AV) block, but a cause-relation is sometimes difficult to prove. Diagnostic methods with high predictive value proven by instruments for safe and sensitive follow-up are needed. A bradycardia-detecting pacemaker was used in patients with bifascicular block, who had been the subjects of pharmacologic stress testing of the His-Purkinje system. Thirty-seven patients were included, of whom 26 had experienced at least 1 syncopal episode of suspected bradycardia origin, and 11 had previously documented transient high-degree AV block. The electrophysiologic study included injection of disopyramide 2 mg/kg (up to 150 mg) over 5 minutes. A positive test result was defined as spontaneous or pacing-induced His-Purkinje high-degree AV block after drug or a drug-induced HV prolongation of > or = 50%. Patients were followed an average 63 months with repeated electrocardiography and a diagnostic pacemaker (n = 23). Altogether, 24 patients had a significant bradycardia diagnosed by either or both methods. The sensitivity and positive predictive values were: HV interval > or = 70 ms at baseline, 47% and 88%; a positive disopyramide test result, 75% and 80%; and HV interval > or = 70 ms or a positive disopyramide test result, 93% and 74%, respectively. Thus, the diagnostic pacemaker is a safe and sensitive tool for evaluating the information obtained at electrophysiologic study, and pharmacologic stress testing with disopyramide has an informative value in patients with bifascicular block and syncope when results at baseline are inconclusive.

Aged↗
PubMed1994

Expression of HLA-DR antigen and smooth muscle cell differentiation markers by valvular fibroblasts in degenerative aortic stenosis.

OBJECTIVES: This study was designed to analyze the functional characteristics of fibroblasts present in aortic valves with degenerative stenosis. BACKGROUND: Morphologic analysis of degenerative stenosis of tricuspid aortic valves has revealed an extensive interstitial fibrosis. METHODS: Stenotic aortic valves collected during aortic valve replacement and control valves collected at autopsy were fixed in formaldehyde, cryosectioned and stained with antibodies against leukocyte markers, HLA-DR and intracellular filaments. Fibroblasts isolated from stenotic valve and skin explants were grown in cell culture, and their proliferative activity was analyzed by cell counting and uptake of tritiated thymidine. RESULTS: In the stenotic valves nearly all interstitial cells expressed vimentin, and approximately 60% of the cells also expressed alpha-actin and desmin. HLA-DR was present on inflammatory cells as well as on one-third of the fibroblast-like cells in the interstitium. Macrophages were found in the interstitium and T lymphocytes close to calcium deposits and in subendothelial areas. In control valves, fibroblasts expressed vimentin but not alpha-actin or desmin. Few inflammatory cells were present in these valves, and HLA-DR expression was restricted to the endothelial surface. In culture, stenotic valve fibroblasts had a reduced ability to proliferate in serum and to activate DNA synthesis in response to growth factors compared with skin fibroblasts from the same patient. CONCLUSIONS: The observation that fibroblasts present in aortic valves with degenerative stenosis express smooth muscle cell characteristics and HLA-DR antigen and show signs of cellular senescence in vitro suggests that they are in a state of chronic activation similar to that observed in fibromatosis and scleroderma lesions.

Actins↗
PubMed1994

Effects of long-term right ventricular apical pacing on left ventricular perfusion, innervation, function and histology.

OBJECTIVES: The purpose of this study was to better understand the effects of long-term right ventricular pacing on left ventricular perfusion, innervation, function and histology. BACKGROUND: Long-term right ventricular apical pacing is associated with increased congestive heart failure and mortality compared with atrial pacing. The exact mechanism for these changes is unknown. In this study, left ventricular perfusion, sympathetic innervation, function and histologic appearance after long-term pacing were studied in dogs in an attempt to see whether basic changes might be present that might ultimately be associated with the adverse clinical outcome. METHODS: A total of 24 dogs were studied. Sixteen underwent radiofrequency ablation of the atrioventricular (AV) junction to produce complete AV block. Seven of these underwent long-term pacing from the right ventricular apex (ventricular paced group), and nine had atrial and right ventricular apical pacing with AV synchrony (dual-chamber paced group). A control group of eight dogs had sham ablations with normal AV conduction. These dogs had atrial pacing only. Regional perfusion and sympathetic innervation were studied in all dogs by imaging with thallium-201 and [I123]metaiodobenzylguanidine, respectively. The degree of innervation was also determined by assay of tissue norepinephrine levels. Left ventricular function was assessed by radionuclide ventriculography. Cardiac histology was studied with both light and electron microscopy. RESULTS: Mismatching of perfusion and innervation in the ventricular paced group was noted, with perfusion abnormalities of both the septum and free wall. Regional [I123]metaiodobenzylguanidine distribution was homogeneous. Tissue norepinephrine levels were elevated in both the ventricular and dual-chamber paced groups compared with the control group. No light or electron microscopic findings were noted in any groups. In the dual-chamber paced group, diastolic dysfunction was noted, with normal systolic function. CONCLUSIONS: Ventricular pacing resulted in regional changes in tissue perfusion and heterogeneity between perfusion and sympathetic innervation. Both ventricular and dual-chamber pacing were associated with an increase in tissue catecholamine activity. The abnormal activation of the ventricles via right ventricular apical pacing may result in multiple abnormalities of cardiac function, which may ultimately affect clinical outcome.

3-Iodobenzylguanidine↗
PubMed1994

Accumulation of T lymphocytes and expression of interleukin-2 receptors in nonrheumatic stenotic aortic valves.

OBJECTIVES: Cell-specific antibodies were used to identify immunocompetent cells in a comparison of valves from patients who had symptomatic tricuspid aortic stenosis with subjects who had no evidence of valvular heart disease. BACKGROUND: Nonrheumatic valvular aortic stenosis is the most common valvular heart disease among adults. The biologic processes involved in the development of this disease are poorly understood. METHODS: Tricuspid stenotic aortic valves were obtained from 19 patients undergoing surgery for nonrheumatic valvular aortic stenosis, and 10 control valves were collected at autopsy. The valves were fixed in formaldehyde, cryosectioned and stained with antibodies against fibroblasts, endothelial cells, macrophages, T lymphocytes and interleukin-2 receptors. A subset of valves were also analyzed with antibodies against T-helper cells and cytotoxic T cells. RESULTS: Stenotic valves were characterized by a basal accumulation of calcium deposits and a cell-rich subendothelial thickening. The immunohistologic analysis indicated that the cells in the subendothelial connective tissue were fibroblasts. T lymphocytes appeared to be the most common cell type in the vicinity of the calcium deposits and were also found close to the endothelial lining of the valves. T-helper cells were more frequent than cytotoxic T cells. Expression of interleukin-2 receptors occurred at the same location as T lymphocytes. Control valves lacked subendothelial thickening and contained only few cells reacting with antibodies against lymphocytes and macrophages. CONCLUSIONS: The presence of activated T lymphocytes in tricuspid stenotic valves suggests that immunologic mechanisms may be involved in the etiology of nonrheumatic aortic stenosis.

Aged↗
PubMed1994

Atrial rate adaptive pacing: what happens to AV conduction?

To investigate if an nonphysiological prolongation of the AV interval is common during activity sensor modulated atrial rate adaptive (AAIR) pacing, 21 patients with sinus node disease treated with fixed rate atrial (AAI) or AAIR pacemakers were examined. Spike-Q intervals were compared at different heart rates obtained by overdrive pacing at rest and during exercise (Study I), measured during exercise at unresponsive (AAI), optimal (AAIR) and over responsive programming (AAIR+) of the activity sensor (Study II), and finally examined by 24-hour Holter recording in AAI and AAIR pacing modes (Study III). Study I: The spike-Q interval increased significantly with increasing heart rate at rest, but not during exercise. At rest the spike-Q interval was significantly higher at all heart rates compared to exercise. There was a significant positive correlation between the maximal spike-Q interval at rest and the maximal spike-Q interval during exercise (r = 0.63). Study II: The spike-Q interval was shortest in the AAI and longest in the AAIR+ mode in all patients. Study III: During AAI or AAIR pacing the spike-Q interval was longest at night and shortest in the morning. The mean spike-Q interval was longer in AAIR than in AAI pacing. No statistical difference between the maximal spike-Q intervals observed during the two modes was, however, found. Variations in spike-Q interval are generally caused by changes in autonomic tone or medication with drugs with antiarrhythmic effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Activities of Daily Living↗