Effects of cardioselective beta-blockade on plasma catecholamines and performance during different forms of exercise

The protective effect of vitamin A on Concor induced structural changes of the liver and kidney in adult rats

Concor is a beta-blocker drug used to treat high blood pressure, acute coronary syndrome, and to control the rapid pulse of the heart such as atrial fibrillation. Some of its adverse effects include hepatitis, increased triglycerides and liver enzymes. Monitoring liver and kidney functions in patients with hepatic or renal impairment who are taking concor is recommended.

The current study was undertaken to define whether vitamin A could improve structural changes in the liver and kidneys. The 24 rats were grouped into the following. The first group was control. The second group was given Vitamin A (5000 IU). Group 3: given concor at a daily dose of 0.9 mg/kg B. wt. Group IV: received concor (0.9 mg/kg B. wt.) and Vitamin A (5000 IU) orally. After 4 weeks, the kidney of the treated group 3 exhibited degenerative alterations in the glomeruli, enlargement of Bowman’s space and the epithelium of the proximal kidney tubules showed vacuolar degeneration with necrosis. Liver sections showed degeneration and necrosis of hepatocytes, congestion of the central vein, dilation of sinusoids and inflammatory cell infiltration. Group 4 showed mild degeneration in the glomeruli, expansion of Bowman’s space and mild degeneration of tubular epithelium, and normal architecture of the liver with increased Kupffer cells. From this study, we concluded that concor drug induces structural changes in the liver and kidney and these effects were improved by Vitamin A administration.

Effects of surgical and FFP2 masks on cardiopulmonary exercise capacity in patients with heart failure

Aims

Surgical and FFP2 masks are recommended to reduce transmission of SARS-CoV-2. The cardiopulmonary effects of facemasks in patients with chronic heart failure are unknown. This prospective, cross-over study quantified the effects of wearing no mask (nm), surgical mask (sm), and FFP2 mask (ffpm) in patients with stable heart failure.

Methods

12 patients with clinically stable chronic heart failure (HF) (age 63.8±12 years, left ventricular ejection fraction (LVEF) 43.8±11%, NTProBNP 573±567 pg/ml) underwent spiroergometry with and without masks in a randomized sequence. Comfort/discomfort was assessed using a standardized questionnaire.

Results

Maximum power was reduced with both types of masks (nm: 108.3 W vs. sm: 101.2 W vs. ffpm: 95.6 W, p<0.01). Maximum respiratory oxygen uptake (1499ml/min vs. 1481 ml/min vs. 1300 ml/min, p = 0.95 and <0.01), peak ventilation (62.1 l/min vs. 56.4 l/min vs. 50.3 l/min, p = 0.15 and p<0.05) and O2-pulse (11.6 ml/beat vs. 11.8 ml/beat vs. 10.6 ml/beat, p = 0.87 and p<0.01) were significantly changed with ffpm but not sm. Discomfort was moderately but significantly increased (nm: 1.6 vs. sm: 3.4 vs. ffpm: 4.4, p<0.05).

Conclusion

Both surgical and FFP masks reduce exercise capacity in heart failure patients, while FFP2 masks reduce oxygen uptake and peak ventilation. This reduction in cardiopulmonary performance should be considered in heart failure patients whose daily life activities are often just as challenging as exercise is for healthy adults.

The Impact of beta blockade on the cardio-respiratory system and symptoms during exercise

Background

Beta blockers prolong life in patients with cardiovascular diseases. Negative chronotropic and inotropic effects carry the potential to adversely effect peripheral skeletal and airway smooth muscle contributing to further fatigue, dyspnea and exercise intolerance.

Research questions

Do beta-blockers reduce maximal power output (MPO), VO2 max, cardiorespiratory responses, increase the perceived effort required to cycle and breath during cardiopulmonary exercise tests (CPET) and limit the capacity to exercise?

Methods

Retrospective observational study of subjects performing CPET to capacity from 1988 to 2012. Subjects with and without beta-blockers were compared: baseline physiological characteristics, MPO, VO₂ max, heart rate max, ventilation responses and perceived exertion required to cycle and breathe (modified Borg scale). Forward stepwise linear additive regression was performed with MPO as the dependent factor with height, age, gender, muscle strength, FEV1 and DLCO as independent contributors.

Results

42,771 subjects were included 7,787 were receiving beta-blocker [mean age 61 yrs, BMI 28.40 kg/m², 9% airflow obstruction (FEV1/FVC<0.7)] and 34,984 were not [mean age 51yrs, BMI 27.40 kg/m², 11% airflow obstruction]. Heart rate was lower by 18.2% (95% C.I. 18.15–18.38) (p<0.0001) while Oxygen pulse (VO₂/HR) was higher by 19.5% (95% C.I. 19.3–19.7) in those receiving beta blockers. Maximum power output (MPO) was 3.3% lower in those taking beta-blockers. The perceived effort required to cycle and breathe (mBorg) was 8% lower in those taking beta-blockers.

Interpretation

Increases in oxygen pulse minimize the reduction in exercise intolerance and symptom handicap associated with beta-blockers.

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Comprehensive set of exercise physiology measurements in a large cohort, to delineate any hazardous effects of beta blockade.

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Beta-blockers attenuate the heart rate at rest and during exercise.

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Beta-blockade has no meaningful effects on muscle strength, breathing capacity or exercise induced bronchoconstriction.

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Beta Blockers were not associated with a reduction in Maximal power output.

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Increases in Oxygen pulse minimize the reduction in exercise intolerance and symptom handicap associated with beta-blockers.