Georg Heinze | Medical University of Vienna (original) (raw)

Papers by Georg Heinze

Methods and results Functional status, the presence of arrhythmias, right ventricular (RV) remode... more Methods and results Functional status, the presence of arrhythmias, right ventricular (RV) remodelling, and pulmonary artery pressure (PAP) were studied in 236 consecutive patients undergoing transcatheter ASD closure [164 females, mean age of 49 ± 18 years, 78 younger than 40 years (Group A), 84 between 40 and 60 years (Group B) and 74 older than 60 years (Group C)]. Defect size [median 22 mm (inter-quartile range, 19, 26 mm)] and shunt ratio [Qp:Qs 2.2 (1.7, 2.9)] did not differ among age groups.

BACKGROUND: Lifestyle parameters, personal history and genetic factors are thought to affect the ... more BACKGROUND: Lifestyle parameters, personal history and genetic factors are thought to affect the timing of natural menopause in humans. Based on their biological function, estrogen-metabolizing gene polymorphisms have been regarded as candidate genes for early menopause.

Abstract The phenomenon of separation or monotone likelihood is observed in the fitting process o... more Abstract The phenomenon of separation or monotone likelihood is observed in the fitting process of a logistic or a Cox model if the likelihood converges while at least one parameter estimate diverges to±infinity. Monotone likelihood primarily occurs in small samples with several unbalanced and highly predictive covariates, and, for Cox regression, with a high percentage of censoring.

Methods and results We conducted a prospective, randomised trial, including 207 patients with AF ... more Methods and results We conducted a prospective, randomised trial, including 207 patients with AF of recent onset (⩽48 h). Flecainide was given over 20 min at a dose of 2 mg/kg body weight (maximum 200 mg), ibutilide was infused at a dose of 1 mg (or 0.01 mg/kg if less than 60 kg) over 10 min, followed by a 10 min observation period and an identical second dose if AF did not convert to sinus rhythm (SR). Treatment was considered successful if SR occurred within 90 min of starting medication.

Abstract Objectives: Feasibility of noninvasive monitoring of cardiac function after surgically i... more Abstract Objectives: Feasibility of noninvasive monitoring of cardiac function after surgically induced ischemic cardiomyopathy with tissue Doppler and non-Doppler 2D strain echocardiography in rats. Background: The optimal method for quantitative assessment of global and regional ventricular function in rats with chronic heart failure for research purposes remains unclear.

Abstract We extend the Tarone and Ware scheme of weighted log-rank tests to cover the associated ... more Abstract We extend the Tarone and Ware scheme of weighted log-rank tests to cover the associated weighted Mantel–Haenszel estimators of relative risk. Weighting functions previously employed are critically reviewed. The notion of an average hazard ratio is defined and its connection to the effect size measure P (Y> X) is emphasized. The connection makes estimation of P (Y> X) possible also under censoring.

Abstract Two SAS macro programs are presented that compute the relative importance of covariates ... more Abstract Two SAS macro programs are presented that compute the relative importance of covariates in the proportional hazards regression model and in the logistic regression model. The relative importance of covariates is quantified by the proportion of explained variation in the outcome (PEV) attributable to those covariates. For proportional hazards regression, the program% RELIMPCR uses the recently proposed measure V to calculate the proportion of explained variation.

Summary. The phenomenon of monotone likelihood is observed in the fitting process of a Cox model ... more Summary. The phenomenon of monotone likelihood is observed in the fitting process of a Cox model if the likelihood converges to a finite value while at least one parameter estimate diverges to±∞. Monotone likelihood primarily occurs in small samples with substantial censoring of survival times and several highly predictive covariates. Previous options to deal with monotone likelihood have been unsatisfactory.

Nach Ihrer Aufgabe lässt sich Statistik grob in deskriptive und schließende Statistik einteilen. ... more Nach Ihrer Aufgabe lässt sich Statistik grob in deskriptive und schließende Statistik einteilen. Während man mit Hilfe der schließenden Statistik durch statistische Tests usw. versucht, Rückschlüsse auf die Population zu ziehen, ist es Aufgabe der deskriptiven Statistik, Stichproben zu beschreiben, und zwar durch

OBJECTIVE: Cervical biopsy often causes discomfort and pain. To compare local anesthesia (1% lido... more OBJECTIVE: Cervical biopsy often causes discomfort and pain. To compare local anesthesia (1% lidocaine) with forced coughing as pain relief, we quantified the actual pain experienced during cervical punch biopsies. STUDY DESIGN: For a prospective trial conducted at the Medical University of Vienna, 68 women undergoing cervical punch biopsies for assessment of abnormal cervical smears were randomized in 2 pain relief treatment groups.

Biostatistik I für medizinische DissertantInnen “erstellt worden. Es soll aber auch nach Absolvie... more Biostatistik I für medizinische DissertantInnen “erstellt worden. Es soll aber auch nach Absolvierung eines dieser Kurse dem/der Lesenden weiter als Nachschlagetext dienen. Das Lehrziel dieser Kurse ist es, mit Hilfe eines Statistikprogrammpaketes wie SPSS Datenbeschreibungen für Publikationen und Vorträge selbst durchführen zu können.

When analyzing survival data, the parameter estimates and consequently the relative risk estimate... more When analyzing survival data, the parameter estimates and consequently the relative risk estimates of a Cox model sometimes do not converge to finite values. This phenomenon is due to special conditions in a data set and is known as 'monotone likelihood'. Statistical software packages for Cox regression using the maximum likelihood method cannot appropriately deal with this problem. A new procedure to solve the problem has been proposed by G. Heinze, M.

Abstract In this study species-specific values for whole blood viscosity (WBV), plasma viscosity ... more Abstract In this study species-specific values for whole blood viscosity (WBV), plasma viscosity (PV) and erythrocyte aggregation (EA) were determined in a total of 360 animals. We used 40 individual adult animals of nine mammalian species: horse, pig, dog, cat, rat, cattle, sheep, rabbit and mouse. WBV measurements were carried out using a LS30 viscometer, PV was measured using OCR-D and EA was measured using a Myrenne aggregometer and the LS30 (aggregation index at low shear rate).

BACKGROUND: The aim of this study was to compare the pain-relieving effect and the subjective wel... more BACKGROUND: The aim of this study was to compare the pain-relieving effect and the subjective well-being between auricular electro-acupuncture (EA) analgesia, auricular acupuncture (A) and conventional analgesia with remifentanil (CO).

Background. Mycophenolate mofetil has replaced azathioprine in many transplant centers, but data ... more Background. Mycophenolate mofetil has replaced azathioprine in many transplant centers, but data on hard outcomes such as graft and patient survival are lacking. Methods. We analyzed graft and patient survival of the 1219 first renal allograft recipients at the Medical University of Vienna who were treated with azathioprine or mycophenolate mofetil over the past decade.

Background and Purpose—There is growing clinical and experimental evidence that infections with C... more Background and Purpose—There is growing clinical and experimental evidence that infections with Chlamydia pneumoniae might contribute to the development and progression of atherosclerosis. However, studies detecting the pathogen in atherosclerotic lesions examined either only atherosclerotic vessels or control vessels without atherosclerosis obtained from a different group of individuals.

Abstract The assessment of treatment effects from observational studies may be biased with patien... more Abstract The assessment of treatment effects from observational studies may be biased with patients not randomly allocated to the experimental or control group. One way to overcome this conceptual shortcoming in the design of such studies is the use of propensity scores to adjust for differences of the characteristics between patients treated with experimental and control interventions.

OBJECTIVES: Strategies to recover myocardium in therapeutically unresponsive patients are again u... more OBJECTIVES: Strategies to recover myocardium in therapeutically unresponsive patients are again under scrutiny, including techniques developed in the pioneering days of cardiothoracic surgery such as retroperfusion via the coronary sinus—the Beck procedure. An underestimated aspect of retroperfusion is the formation of new vessels. This early observation of neoangiogenesis may be an important mechanism in observed benefits.

Methods and results Functional status, the presence of arrhythmias, right ventricular (RV) remode... more Methods and results Functional status, the presence of arrhythmias, right ventricular (RV) remodelling, and pulmonary artery pressure (PAP) were studied in 236 consecutive patients undergoing transcatheter ASD closure [164 females, mean age of 49 ± 18 years, 78 younger than 40 years (Group A), 84 between 40 and 60 years (Group B) and 74 older than 60 years (Group C)]. Defect size [median 22 mm (inter-quartile range, 19, 26 mm)] and shunt ratio [Qp:Qs 2.2 (1.7, 2.9)] did not differ among age groups.

BACKGROUND: Lifestyle parameters, personal history and genetic factors are thought to affect the ... more BACKGROUND: Lifestyle parameters, personal history and genetic factors are thought to affect the timing of natural menopause in humans. Based on their biological function, estrogen-metabolizing gene polymorphisms have been regarded as candidate genes for early menopause.

Abstract The phenomenon of separation or monotone likelihood is observed in the fitting process o... more Abstract The phenomenon of separation or monotone likelihood is observed in the fitting process of a logistic or a Cox model if the likelihood converges while at least one parameter estimate diverges to±infinity. Monotone likelihood primarily occurs in small samples with several unbalanced and highly predictive covariates, and, for Cox regression, with a high percentage of censoring.

Methods and results We conducted a prospective, randomised trial, including 207 patients with AF ... more Methods and results We conducted a prospective, randomised trial, including 207 patients with AF of recent onset (⩽48 h). Flecainide was given over 20 min at a dose of 2 mg/kg body weight (maximum 200 mg), ibutilide was infused at a dose of 1 mg (or 0.01 mg/kg if less than 60 kg) over 10 min, followed by a 10 min observation period and an identical second dose if AF did not convert to sinus rhythm (SR). Treatment was considered successful if SR occurred within 90 min of starting medication.

Abstract Objectives: Feasibility of noninvasive monitoring of cardiac function after surgically i... more Abstract Objectives: Feasibility of noninvasive monitoring of cardiac function after surgically induced ischemic cardiomyopathy with tissue Doppler and non-Doppler 2D strain echocardiography in rats. Background: The optimal method for quantitative assessment of global and regional ventricular function in rats with chronic heart failure for research purposes remains unclear.

Abstract We extend the Tarone and Ware scheme of weighted log-rank tests to cover the associated ... more Abstract We extend the Tarone and Ware scheme of weighted log-rank tests to cover the associated weighted Mantel–Haenszel estimators of relative risk. Weighting functions previously employed are critically reviewed. The notion of an average hazard ratio is defined and its connection to the effect size measure P (Y> X) is emphasized. The connection makes estimation of P (Y> X) possible also under censoring.

Abstract Two SAS macro programs are presented that compute the relative importance of covariates ... more Abstract Two SAS macro programs are presented that compute the relative importance of covariates in the proportional hazards regression model and in the logistic regression model. The relative importance of covariates is quantified by the proportion of explained variation in the outcome (PEV) attributable to those covariates. For proportional hazards regression, the program% RELIMPCR uses the recently proposed measure V to calculate the proportion of explained variation.

Summary. The phenomenon of monotone likelihood is observed in the fitting process of a Cox model ... more Summary. The phenomenon of monotone likelihood is observed in the fitting process of a Cox model if the likelihood converges to a finite value while at least one parameter estimate diverges to±∞. Monotone likelihood primarily occurs in small samples with substantial censoring of survival times and several highly predictive covariates. Previous options to deal with monotone likelihood have been unsatisfactory.

Nach Ihrer Aufgabe lässt sich Statistik grob in deskriptive und schließende Statistik einteilen. ... more Nach Ihrer Aufgabe lässt sich Statistik grob in deskriptive und schließende Statistik einteilen. Während man mit Hilfe der schließenden Statistik durch statistische Tests usw. versucht, Rückschlüsse auf die Population zu ziehen, ist es Aufgabe der deskriptiven Statistik, Stichproben zu beschreiben, und zwar durch

OBJECTIVE: Cervical biopsy often causes discomfort and pain. To compare local anesthesia (1% lido... more OBJECTIVE: Cervical biopsy often causes discomfort and pain. To compare local anesthesia (1% lidocaine) with forced coughing as pain relief, we quantified the actual pain experienced during cervical punch biopsies. STUDY DESIGN: For a prospective trial conducted at the Medical University of Vienna, 68 women undergoing cervical punch biopsies for assessment of abnormal cervical smears were randomized in 2 pain relief treatment groups.

Biostatistik I für medizinische DissertantInnen “erstellt worden. Es soll aber auch nach Absolvie... more Biostatistik I für medizinische DissertantInnen “erstellt worden. Es soll aber auch nach Absolvierung eines dieser Kurse dem/der Lesenden weiter als Nachschlagetext dienen. Das Lehrziel dieser Kurse ist es, mit Hilfe eines Statistikprogrammpaketes wie SPSS Datenbeschreibungen für Publikationen und Vorträge selbst durchführen zu können.

When analyzing survival data, the parameter estimates and consequently the relative risk estimate... more When analyzing survival data, the parameter estimates and consequently the relative risk estimates of a Cox model sometimes do not converge to finite values. This phenomenon is due to special conditions in a data set and is known as 'monotone likelihood'. Statistical software packages for Cox regression using the maximum likelihood method cannot appropriately deal with this problem. A new procedure to solve the problem has been proposed by G. Heinze, M.

Abstract In this study species-specific values for whole blood viscosity (WBV), plasma viscosity ... more Abstract In this study species-specific values for whole blood viscosity (WBV), plasma viscosity (PV) and erythrocyte aggregation (EA) were determined in a total of 360 animals. We used 40 individual adult animals of nine mammalian species: horse, pig, dog, cat, rat, cattle, sheep, rabbit and mouse. WBV measurements were carried out using a LS30 viscometer, PV was measured using OCR-D and EA was measured using a Myrenne aggregometer and the LS30 (aggregation index at low shear rate).

BACKGROUND: The aim of this study was to compare the pain-relieving effect and the subjective wel... more BACKGROUND: The aim of this study was to compare the pain-relieving effect and the subjective well-being between auricular electro-acupuncture (EA) analgesia, auricular acupuncture (A) and conventional analgesia with remifentanil (CO).

Background. Mycophenolate mofetil has replaced azathioprine in many transplant centers, but data ... more Background. Mycophenolate mofetil has replaced azathioprine in many transplant centers, but data on hard outcomes such as graft and patient survival are lacking. Methods. We analyzed graft and patient survival of the 1219 first renal allograft recipients at the Medical University of Vienna who were treated with azathioprine or mycophenolate mofetil over the past decade.

Background and Purpose—There is growing clinical and experimental evidence that infections with C... more Background and Purpose—There is growing clinical and experimental evidence that infections with Chlamydia pneumoniae might contribute to the development and progression of atherosclerosis. However, studies detecting the pathogen in atherosclerotic lesions examined either only atherosclerotic vessels or control vessels without atherosclerosis obtained from a different group of individuals.

Abstract The assessment of treatment effects from observational studies may be biased with patien... more Abstract The assessment of treatment effects from observational studies may be biased with patients not randomly allocated to the experimental or control group. One way to overcome this conceptual shortcoming in the design of such studies is the use of propensity scores to adjust for differences of the characteristics between patients treated with experimental and control interventions.

OBJECTIVES: Strategies to recover myocardium in therapeutically unresponsive patients are again u... more OBJECTIVES: Strategies to recover myocardium in therapeutically unresponsive patients are again under scrutiny, including techniques developed in the pioneering days of cardiothoracic surgery such as retroperfusion via the coronary sinus—the Beck procedure. An underestimated aspect of retroperfusion is the formation of new vessels. This early observation of neoangiogenesis may be an important mechanism in observed benefits.