Nitroglycerin has long been famous for its relief of angina pectoris a

Question

Nitroglycerin has long been famous for its relief of angina pectoris attacks but ruled out for heart attacks on the theory that it harmfully lowers blood pressure and increases heart rate. A heart attack, unlike an angina attack, always involves some localized, fairly rapid heart muscle death, or myocardial infarction. This acute emergency happens when the art eriosclerotic occlusive process in one of the coronary arterial branches culminates so suddenly and completely that the local myocardium—the muscle area that was fed by the occluded coronary— stops contracting and dies over a period of hours, to be replaced over a period of weeks by a scar, or “healed infarct.” In 1974, in experiments with dogs, it was discovered that administration of nitroglycerin during the acute stage of myocardial infarction consistently reduced the extent of myocardial injury, provided that the dogs’ heart rate and blood pressure were maintained in the normal range.

Soon after, scientists made a preliminary confirmation of the clinical applicability of nitroglycerin in acute heart attack in human patients. Five of twelve human subjects developed some degree of congestive heart failure. Curiously, the nitroglycerin alone was enough to reduce the magnitude of injury in these five patients, but the other seven patients, whose heart attacks were not complicated by any congestive heart failure, were not consistently helped by the nitroglycerin until another drug, phenylephrine, was added to abolish the nitroglycerin-induced drop in blood pressure. One explanation for this is that the reflex responses in heart rate, mediated through the autonomic nervous system, are so blunted in congestive heart failure that a fall in blood pressure prompts less of the cardiac acceleration which otherwise worsens the damage of acute myocardial infarction. It appears that the size of the infarct that would otherwise result from a coronary occlusion might be greatly reduced,and vitally needed heart muscle thus saved, by the actions of certain drugs and other measures taken during the acute phase of the heart attack. This is because the size of the myocardial infarct is not really determined at the moment of the coronary occlusion as previously thought.

The fate of the stricken myocardial segment remains largely undetermined, hanging on the balance of myocardial oxygen supply and demand which can be favorably influenced for many hours after the coronary occlusion. So it is possible to reduce the myocardial ischemic injury during acute human heart attacks by means of nitroglycerin, either alone or in combination with phenylephrine. Other drugs are also being tested to reduce myocardial infarct size, particularly drugs presumed to affect myocardial oxygen supply and demand, including not only vessel dilators such as nitroglycerin but also antihypertensives, which block the sympathetic nerve reflexes that increase heart rate and work in response to exertion and stress. Such measures are still experimental, and there is no proof of benefit with regard to the great complications of heart attack such as cardiogenic shock, angina, or mortality. But the drugs for reducing infarct size now hold center stage in experimental frameworks.   1 
 1. According to the passage, the primary difference between a heart attack and an angina attack is that a heart attack

(A) involves an acceleration of the heartbeat
(B) cannot be treated with nitroglycerin
(C) generally results in congestive heart failure
(D) takes place within a relatively short period of time
(E) always results in damage to muscle tissue of the heart

2 
 2. The patients who developed congestive heart failure did not experience cardiac acceleration because

(A) the nitroglycerin was not administered soon enough after the onset of the heart attack
(B) the severity of the heart attack blocked the autonomic response to the nitroglycerin-induced drop in blood pressure
(C) administering phenylephrine mitigated the severity of the drop in blood pressure caused by nitroglycerin
(D) doctors were able to maintain blood pressure, and thus indirectly pulse rate, in those patients
(E) those patients did not experience a drop in blood pressure as a result of the heart attack

3 
 3. The passage provides information to answer all of the following questions EXCEPT

(A) What are some of the physiological manifestations of a heart attack?
(B) What determines the size of a myocardial infarct following a heart attack?
(C) What effect does nitroglycerin have when administered to a patient experiencing a heart attack?
(D) What are the most important causes of heart attacks?
(E) What is the physiological effect of phenylephrine?

4 
 4. It can be inferred from the passage that nitroglycerin is of value in treating heart attacks because it

(A) lowers the blood pressure
(B) stimulates healing of an infarct
(C) causes cardiac acceleration
(D) dilates blood vessels
(E) counteracts hypertension

5 
 5. The author’s attitude toward the use of nitroglycerin and other drugs to treat heart attack can best be described as one of

(A) concern
(B) resignation
(C) anxiety
(D) disinterest
(E) optimism

6 
 6. It can be inferred that the phenylephrine is administered in conjunction with nitroglycerin during a heart attack in order to

(A) prevent the cardiac acceleration caused by a drop in blood pressure
(B) block sympathetic nerve reflexes that increase the pulse rate
(C) blunt the autonomic nervous system which accelerates the pulse rate
(D) reduce the size of a myocardial infarct by increasing oxygen supply
(E) prevent arteriosclerotic occlusion in the coronary arterial branches

tarunanandani · Accepted Answer

Nitroglycerin has long been famous for its relief of angina pectoris attacks but ruled out for heart attacks on the theory that it harmfully lowers blood pressure and increases heart rate. A heart attack, unlike an angina attack, always involves some localized, fairly rapid heart muscle death, or myocardial infarction. This acute emergency happens when the art eriosclerotic occlusive process in one of the coronary arterial branches culminates so suddenly and completely that the local myocardium—the muscle area that was fed by the occluded coronary— stops contracting and dies over a period of hours, to be replaced over a period of weeks by a scar, or “healed infarct.” In 1974, in experiments with dogs, it was discovered that administration of nitroglycerin during the acute stage of myocardial infarction consistently reduced the extent of myocardial injury, provided that the dogs’ heart rate and blood pressure were maintained in the normal range.

Soon after, scientists made a preliminary confirmation of the clinical applicability of nitroglycerin in acute heart attack in human patients. Five of twelve human subjects developed some degree of congestive heart failure. Curiously, the nitroglycerin alone was enough to reduce the magnitude of injury in these five patients, but the other seven patients, whose heart attacks were not complicated by any congestive heart failure, were not consistently helped by the nitroglycerin until another drug, phenylephrine, was added to abolish the nitroglycerin-induced drop in blood pressure. One explanation for this is that the reflex responses in heart rate, mediated through the autonomic nervous system, are so blunted in congestive heart failure that a fall in blood pressure prompts less of the cardiac acceleration which otherwise worsens the damage of acute myocardial infarction. It appears that the size of the infarct that would otherwise result from a coronary occlusion might be greatly reduced,and vitally needed heart muscle thus saved, by the actions of certain drugs and other measures taken during the acute phase of the heart attack. This is because the size of the myocardial infarct is not really determined at the moment of the coronary occlusion as previously thought.

The fate of the stricken myocardial segment remains largely undetermined, hanging on the balance of myocardial oxygen supply and demand which can be favorably influenced for many hours after the coronary occlusion. So it is possible to reduce the myocardial ischemic injury during acute human heart attacks by means of nitroglycerin, either alone or in combination with phenylephrine. Other drugs are also being tested to reduce myocardial infarct size, particularly drugs presumed to affect myocardial oxygen supply and demand, including not only vessel dilators such as nitroglycerin but also antihypertensives, which block the sympathetic nerve reflexes that increase heart rate and work in response to exertion and stress. Such measures are still experimental, and there is no proof of benefit with regard to the great complications of heart attack such as cardiogenic shock, angina, or mortality. But the drugs for reducing infarct size now hold center stage in experimental frameworks.

1. According to the passage, the primary difference between a heart attack and an angina attack is that a heart attack

Correct  answer is (E) , always results in damage to muscle tissue of the heart
The relevant text in the passage is highlighted in blue color.

2. The patients  who developed congestive heart failure  did not experience cardiac acceleration because

(A) the nitroglycerin was not administered soon enough after the onset of the heart attack -- Incorrect , time of administration is not mentioned in the passage.
(B) the severity of the heart attack blocked the autonomic response to the nitroglycerin-induced drop in blood pressure -- Correct , reference text is in pink color.
(C) administering phenylephrine mitigated the severity of the drop in blood pressure caused by nitroglycerin -- Incorrect , this option is true for the patients who did not develop congestive heart failure. Reference text is in red color.
(D) doctors were able to maintain blood pressure, and thus indirectly pulse rate, in those patients -- Incorrect , not mentioned.
(E) those patients did not experience a drop in blood pressure as a result of the heart attack -- Incorrect , not mentioned.

3. The passage provides information to answer all of the following questions EXCEPT

Straight D , the causes of heart attacks have never been mentioned in the passage.

4. It can be inferred from the passage that nitroglycerin is of value in treating heart attacks because it

Answer is D . Reference text: 'particularly drugs presumed to affect myocardial oxygen supply and demand, including not only vessel dilators such as nitroglycerin' (highlighted by green color)
Option B is tempting but is incorrect because the size of an infarct has been discussed in the passage, not healing.

5. The author’s attitude toward the use of nitroglycerin and other drugs to treat heart attack can best be described as one of

Since the author's tone is positive or neutral throughout the passage so all the options except E are wrong because all of them describes a negative tone.  Hence E , optimism, is the answer.

6. It can be inferred that the phenylephrine is administered in conjunction with nitroglycerin during a heart attack in order to

Clearly A  is the answer. Reference text: '...were not consistently helped by the nitroglycerin until another drug, phenylephrine, was added to abolish the nitroglycerin-induced drop in blood pressure' (highlighted by red color in the passage).

Cinematiccuisine · Answer

tarunanandani

for Q1: Why choice D is incorrect?
In fact, the para says -->  always involves  some localized,  fairly rapid  heart muscle death

i know that if i simply the sentence then it's clear that phenomenon involves muscle death, but it also can be interpreted as " takes place within a relatively short period of time."

In general, how much time did you take in solving this para? Please recommend a strategy if you are aware. 
thanks in advance.

tarunanandani · Answer

Hi  Cinematiccuisine ,

Q1 asks the difference  between heart attack and angina attack . Now lets see the lines in the para:
'A heart attack, unlike an angina attack,  always involves  some localized,  fairly rapid heart muscle death , or myocardial infarction.'
Notice that the word 'rapid' is modifying heart muscle death and not the heart attack i.e., the muscle death takes place in a short duration of time. So, the para doesn't support the fact that heart attack itself is rapid than the angina attack. Hence option D is incorrect.

For this particular passage I took almost 11 mins, including reading time, to solve all the 6 questions and got 5 correct. I'm trying to follow the strategies described in Manhattan RC GMAT Strategy Guide, particularly for this type of passages. 
This passage is very dense and complicated so it is important to understand the structure of the passage without spending too much time on the details. If one is able to able to understand the main point of the passage then it is easy to answer global questions such as Q3, Q6 in this passage. At last, I think practice is the key to apply strategies mentioned in Manhattan RC guide. So, big thanks to  workout  to give us the opportunity to practice such challenging passages everyday.

Hope this helps!

Cinematiccuisine · Answer

Thank you  tarunanandani  for providing the details. Yes, it's clear now.

And yes, thank you  workout  for the daily RC questionnaire. It's really helpful.

I am sorry, I know that my reply doesn't really align with rules for posting/replying. but wanted to convey my regards to GMAT community. Thanks.

arshiyakhanna · Answer

This is a tough passage. The key is not understand the structure and not get lost in details and use POE. Also, be aware of inconsistent choices - mainly contains a word that changes the meaning.

1. According to the passage, the primary difference between a heart attack and an angina attack is that a heart attack

(A) involves an acceleration of the heartbeat 
(B) cannot be treated with nitroglycerin
(C) generally results in congestive heart failure
(D) takes place within a relatively short period of time - agina attach could also be for a short period, the focus is on muscle injury
(E) always results in damage to muscle tissue of the heart

A heart attack, unlike an angina attack,  always involves  some localized, fairly  rapid heart muscle death ,  or myocardial infarction.

2. The patients who developed congestive heart failure did not experience cardiac acceleration because

(A) the nitroglycerin was not administered soon enough after the onset of the heart attack - not given
(B) the severity of the heart attack blocked the autonomic response to the nitroglycerin-induced drop in blood pressure - correct
(C) administering phenylephrine mitigated the severity of the drop in blood pressure caused by nitroglycerin - this was done for patients who didn't have congestive heart failure
(D) doctors were able to maintain blood pressure, and thus indirectly pulse rate, in those patients
(E) those patients did not experience a drop in blood pressure as a result of the heart attack

One explanation for this is that the reflex responses in heart rate, mediated through the autonomic nervous system, are so blunted in congestive heart failure that a fall in blood pressure prompts less of the cardiac acceleration which otherwise worsens the damage of acute myocardial infarction.

3. The passage provides information to answer all of the following questions EXCEPT

(A) What are some of the physiological manifestations of a heart attack? - given
(B) What determines the size of a myocardial infarct following a heart attack? - passage talks about the size of myocardial infarct 
(C) What effect does nitroglycerin have when administered to a patient experiencing a heart attack? - clearly stated 
(D) What are the most important causes of heart attacks?
(E) What is the physiological effect of phenylephrine? - given

It's better if you know the meaning of physiological - deals with the normal functions of living organisms and their parts

4. It can be inferred from the passage that nitroglycerin is of value in treating heart attacks because it

(A) lowers the blood pressure - opposite effect 
(B) stimulates healing of an infarct - talks about the size, nor healing => inconsistent choice
(C) causes cardiac acceleration - opposite 
(D) dilates blood vessels
(E) counteracts hypertension - not mentioned

Used POE

5. The author’s attitude toward the use of nitroglycerin and other drugs to treat heart attack can best be described as one of

(A) concern
(B) resignation
(C) anxiety
(D) disinterest
(E) optimism

Easiest if you understand the structure/tone of the passage, specially last paragraph.

6. It can be inferred that the phenylephrine is administered in conjunction with nitroglycerin during a heart attack in order to

(A) prevent the cardiac acceleration caused by a drop in blood pressure - clearly stated
(B) block sympathetic nerve reflexes that increase the pulse rate
(C) blunt the autonomic nervous system which accelerates the pulse rate
(D) reduce the size of a myocardial infarct by increasing oxygen supply
(E) prevent arteriosclerotic occlusion in the coronary arterial branches

Curiously, the nitroglycerin alone was enough to reduce the magnitude of injury in these five patients, but the other seven patients, whose heart attacks were not complicated by any congestive heart failure, were not consistently helped by the nitroglycerin until another drug, phenylephrine, was added to abolish the nitroglycerin-induced drop in blood pressure.

VerbalBot · Answer

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Nitroglycerin has long been famous for its relief of angina pectoris a

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Nitroglycerin has long been famous for its relief of angina pectoris a

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