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Biomedical subjects

Michael Kindermann

Publications and source records attributed to Michael Kindermann.

10 recordsLinked to original sources
PubMed2006

Soccer world championship: a challenge for the cardiologist.

The 18th FIFA Soccer World Cup 2006 in Germany enthused millions of people worldwide, but only little is known about the association of such an event with cardiovascular events. Modest physical activity is known to reduce the cardiovascular risk significantly. On the other hand, vigorous physical activity and emotional strain increase the cardiovascular risk and the incidence of cardiovascular events likely due to an increased sympathetic tone with consecutive catecholamine stimulation of the heart. Few reviews and case-reports are dealing with the risk of physical activity in cardiovascular high-risk patients or athletes with congenital heart diseases (e.g. hypertrophic obstructive cardiomyopathy), but the impact of highly competitive events on cardiovascular events, especially in spectators were rarely addressed. Thus, the increased risk of cardiovascular events in players and spectators were addressed in this review with respect to various soccer matches and tournaments, such as the FIFA World Cup.

Heart Diseases↗
PubMed2006

Biventricular versus conventional right ventricular stimulation for patients with standard pacing indication and left ventricular dysfunction: the Homburg Biventricular Pacing Evaluation (HOBIPACE).

OBJECTIVES: The Homburg Biventricular Pacing Evaluation (HOBIPACE) is the first randomized controlled study that compares the biventricular (BV) pacing approach with conventional right ventricular (RV) pacing in patients with left ventricular (LV) dysfunction and a standard indication for antibradycardia pacing in the ventricle. BACKGROUND: In patients with LV dysfunction and atrioventricular block, conventional RV pacing may yield a detrimental effect on LV function. METHODS: Thirty patients with standard indication for permanent ventricular pacing and LV dysfunction defined by an LV end-diastolic diameter > or =60 mm and an ejection fraction < or =40% were included. Using a prospective, randomized crossover design, three months of RV pacing were compared with three months of BV pacing with regard to LV function, N-terminal pro-B-type natriuretic peptide (NT-proBNP) serum concentration, exercise capacity, and quality of life. RESULTS: When compared with RV pacing, BV stimulation reduced LV end-diastolic (-9.0%, p = 0.022) and end-systolic volumes (-16.9%, p < 0.001), NT-proBNP level (-31.0%, p < 0.002), and the Minnesota Living with Heart Failure score (-18.9%, p = 0.01). Left ventricular ejection fraction (+22.1%), peak oxygen consumption (+12.0%), oxygen uptake at the ventilatory threshold (+12.5%), and peak circulatory power (+21.0%) were higher (p < 0.0002) with BV pacing. The benefit of BV over RV pacing was similar for patients with (n = 9) and without (n = 21) atrial fibrillation. Right ventricular function was not affected by BV pacing. CONCLUSIONS: In patients with LV dysfunction who need permanent ventricular pacing support, BV stimulation is superior to conventional RV pacing with regard to LV function, quality of life, and maximal as well as submaximal exercise capacity.

Aged↗
PubMed2004

Carvedilol but not metoprolol reduces beta-adrenergic responsiveness after complete elimination from plasma in vivo.

BACKGROUND: Carvedilol but not metoprolol exhibits persistent binding to beta-adrenergic receptors (beta-ARs) even after washout in cell culture experiments. Here, we determined the significance of this phenomenon on human beta-ARs in vitro and in vivo. METHODS AND RESULTS: Experiments were conducted on human atrial trabeculae (n=8 to 10 per group). In the presence of metoprolol, isoproterenol potency was reduced compared with controls (P<0.001). In the presence of carvedilol, isoproterenol identified 2 distinct binding sites of high (36+/-6%; -8.8+/-0.4 log mol/L) and low affinity (-6.5+/-0.2 log mol/L). After beta-blocker washout, isoproterenol potency returned to control values in metoprolol-treated muscles, whereas in carvedilol-treated preparations, isoproterenol potency remained decreased (P<0.001 versus control). In vivo studies were performed in 9 individuals receiving metoprolol succinate (190 mg/d) or carvedilol (50 mg/d) for 11 days in a randomized crossover design. Dobutamine stress echocardiography (5 to 40 microg x kg(-1) x min(-1)) was performed before, during, and 44 hours after application of study medication. Beta-blocker medication reduced heart rate, heart rate-corrected velocity of circumferential fiber shortening, and cardiac output compared with baseline (P<0.02 to 0.0001). After withdrawal of metoprolol, all parameters returned to baseline values, whereas after carvedilol, all parameters remained reduced (P<0.05 to 0.001) despite complete plasma elimination of carvedilol. CONCLUSIONS: Carvedilol but not metoprolol inhibits the catecholamine response of the human heart beyond its plasma elimination. The persistent beta-blockade by carvedilol may be explained by binding of carvedilol to an allosteric site of beta-ARs.

Adrenergic alpha-Antagonists↗
PubMed2004

Selective site pacing: the right ventricular approach.

Animal data and recent findings in humans have questioned the appropriateness of pacing the heart from the right ventricular apex. Numerous, mostly small sized, studies have evaluated alternative sites within the right ventricle. There is now sufficient evidence that right ventricular apical pacing in patients with left ventricular dysfunction with or without heart failure is detrimental. Pacing from the right side of the heart as an attempt at nonpharmacological therapy for heart failure, turns out to be obsolete. In antibradycardia pacing with the need for continuous ventricular support, the interest in preserving left ventricular function drives the ongoing search for the most favorable pacing site within the right ventricle. Results, so far, are conflicting which may be attributed to the inhomogeneity of patient groups, the small cohorts studied, the differing protocols used, and the lack of accepted definitions of right ventricular lead positions. Larger studies are needed to evaluate intraoperative criteria for optimal lead placement and the potential benefit of nonapical right ventricular pacing.

Cardiac Pacing, Artificial↗
PubMed2004

Exercise programmes for patients with chronic heart failure.

The safety and efficacy of exercise training in patients with chronic heart failure (CHF) have been reported in a large number of scientific studies, with endurance training representing the most frequently applied training stimulus. Beneath the common continuous method of endurance training, the interval method (short bouts of intense exercise interspersed with pre-scheduled rest intervals), was also applied in some studies. Ergometric testing is a prerequisite for all individualised training prescription and is an appropriate method of efficacy documentation. However, there is a surprisingly large range of exercise intensities being prescribed to patients with CHF. Most of the prescription models refer to maximal ergometric measurements. Submaximal references from lactate and ventilatory curves represent an alternative method in measuring accuracy and efficacy of training. The course of heart rate during submaximal incremental exercise can be reliably used to indicate endurance gains in CHF. Some positive reports exist for carefully executed strength endurance training for patients with CHF and there are convincing arguments for the use of coordination and flexibility exercises; however, substantial scientific evidence is lacking.

Cardiovascular System↗
PubMed2003

[Exercise training in heart failure].

BACKGROUND: In patients with chronic heart failure, exercise limitation cannot be exclusively attributed to cardiac dysfunction. During progression of the disease, peripheral factors have a growing impact on functional capacity. Chronic underperfusion of skeletal muscles, inactivity and a harmful effect of neuroendocrine stimulation lead to a myopathy syndrome characterized by atrophy, a shift in muscle fiber type and a loss of capillaries and mitochondria, which cause reduced muscle strength and aerobic capacity. Unlike left ventricular systolic function, which is a poor predictor of exercise tolerance in patients with chronic heart failure, parameters characterizing the myopathy syndrome correlate well with functional capacity. In the last 20 years, numerous studies have demonstrated that chronic heart failure patients in NYHA classes II and III benefit from physical training without deterioration of their cardiac function. EFFECTS OF EXERCISE TRAINING: Physical activity primarily improves muscle function and increases maximal as well as submaximal exercise capacity. Advantageous effects have also been observed with regard to neuroendocrine stimulation. The effect on central hemodynamics is much smaller and indirectly mediated by a trend towards decreased peripheral resistance. Left ventricular diameters, ejection fraction and filling pressures do not show significant changes. The gain in exercise capacity is usually accompanied by an improvement in symptom status and quality of life. Recent studies indicate that prognosis may also be improved by exercise training. CONVERSION INTO CLINICAL PRACTICE: Although continuous exercise training (mainly by use of cycle ergometry) has been investigated most thoroughly, there is an increasing number of studies reporting beneficial effects of interval and resistance training. Before starting a standardized training program, functional limitation and training intensity should be determined by an appropriate stress test. During the first training sessions, patients should always be supervised by a physician. In order to increase efficiency and feasibility of the exercise therapy, home-based training should be engaged as soon as a stable condition during repeated training sessions has been proven.

Chronic Disease↗