Class IV antidysrhythmics or calcium channel blockers have what action on the cardiovascular system?

Lifestyle is the greatest contributing factor that can lead to many diseases, especially noncommunicable diseases (NCDs) such as cardiovascular diseases, cancers, chronic respiratory diseases and diabetes.According to the World Health Organization (WHO), NCDs are responsible for 74% of all deaths worldwide, and they share four major risk factors: tobacco use, physical inactivity, the harmful use of alcohol and unhealthy diets.These modifiable behaviours increase the risk of metabolic risk factors such as raised blood pressure, increased blood glucose, elevated blood lipids and obesity, which can lead to NCDs.

Choice A is wrong because trauma is not a factor that can lead to many diseases, but rather a result of injuries or accidents that damage the body.Trauma can cause acute or chronic conditions, such as infections, bleeding, fractures, organ failure or post-traumatic stress disorder, but it is not a common cause of NCDs.

Choice C is wrong because congenital means present at birth or inherited.

Congenital diseases are caused by genetic mutations or environmental factors that affect the development of the fetus.

Some examples of congenital diseases are Down syndrome, cystic fibrosis, congenital heart defects and spina bifida.

Congenital diseases are not the greatest contributing factor to many diseases because they are relatively rare and often detected early.

Choice D is wrong because genetics refers to the inherited traits from parents that influence the risk of developing certain diseases.

Genetics can play a role in some NCDs, such as cancers, diabetes and some cardiovascular diseases, but it is not the only or the most important factor.

Genetics interacts with environmental and lifestyle factors to determine the likelihood of developing a disease.

Therefore, genetics alone cannot lead to many diseases.

Positive inotropy and negative chronotropy.Digoxin is a cardiac glycoside that increases the force of the heart contractions (positive inotropy) and slows down the heart rate (negative chronotropy).

Choice A is wrong because positive chronotropy means increasing the heart rate, which is the opposite of what digoxin does.

Choice B is wrong because negative inotropy means decreasing the force of the heart contractions, which is also the opposite of what digoxin does.

Choice D is wrong because positive chronotropy means increasing the heart rate, which is not what digoxin does.

Digoxin is used to treat heart failure and atrial fibrillation, a type of irregular heartbeat.It has a narrow therapeutic window, meaning that the dose must be carefully adjusted to avoid toxicity or ineffectiveness.