Identify which of the following six types of study designs most appropriately characterizes the situation described below. You are interested in finding out whether middle-aged men who have premature ventricular contractions (PVCs) are at greater risk of developing a myocardial infarction (heart attack) than men whose heartbeats are regular. Electrocardiogram (ECG) examinations are performed on all male office employees 35 years of age or older who work for oil companies in Houston. The ECG tracings are classified as irregular or regular. Five years later, myocardial infarction rates are compared between those with and those without baseline ECG irregularities. a. Cross-sectional study
b. Case-control study
c. Prospective cohort study
d. Historical prospective cohort study
e. Clinical trial
f Community trial

c. Prospective cohort study

Explanation:

Prospective cohort study is a type of observational study which is used to study large number of subjects which are similar but vary with respect to certain factors required to be considered under the study. This is done to determine how these factors affect the rates of certain outcomes. The subjects are studied under different frames.

Here, in the given study the subjects are the same which is a group of middle aged men. These are at a risk of premature ventricular contractions thus are at greater risk of myocardial infraction as compared to men those heartbeats are regular. Here there are different factors to be observed upon and the subjects are also studied in different time frames thus this condition is an example of prospective cohort study.

the correct answer is b