STUDY - Technical - New Dacian's Medicine
Cardiovascular
Collapse, Cardiac Arrest and Sudden Cardiac Death (2)
Translation Draft
So, we've come to the presentation of the clinical characteristics of cardiac arrest and we're going to start with the prodrom, the onset, cardiac arrest and the exitus.
Sudden cardiac death (MSC) may be preceded by days, weeks or months of worsening angina, dyspnoea, palpitations, fatigue or other nonspecific symptoms. However, prodromal charges are generally predictive of any major cardiac risk, not specific to MSC.
The onset of the terminal event, leading to cardiac arrest, is defined as an acute change in cardiovascular status, preceding cardiac arrest by up to one hour. When the onset is brutal or instantaneous, the probability of the stop being of cardiac origin is greater than 95%. Continuous ECG records, made by chance at the onset of cardiac arrest, usually show changes in the heart's heart activity in the minutes or hours before the event.
There is a tendency to increase heart rate and the occurrence of advanced premature ventricular contractions (CVPs). Most cardiac arrests occurring through the ventricular fibrillation (Vf) mechanism begin with episodes of sustained or unsupported ventricular tachycardia (TV), which then degenerates into Vf. The sudden and unexpected decrease in actual circulation can be separated into "arrhythmic events" and "circulatory failure".
Arrhythmic events occur characteristically in patients in a waking state and active just before the event, have as a dominant electrical mechanism FV and a short duration of terminal state (less than one hour). In contrast, death from circulatory insufficiency occurs in inactive or comatose patients with a higher incidence of asystolia than FV, a tendency to a longer duration of terminal condition and cardiac events are dominant before the onset of terminal state.
The onset of cardiac arrest can be characterized by symptoms typical of an acute cardiac event, such as prolonged angina or onset pain from myocardial infarction, acute dyspnoea or ortopnea, palpitations, sustained tachycardia or sudden lye. However, many patients onset is precipitated without prodrom.
Cardiac arrest is by definition brutal. Thinking may be affected in patients with sustained TV during the installation of the terminal event. However, complete loss of consciousness is a sine qua non condition in cardiac arrest. Although spontaneous improvements rarely occur, cardiac arrest usually progresses to exitus within minutes (i.e. MSC occurs) if prompt intervention is not taken.
The success of the attempt to resuscitate the cardiac arrest patient is related to the time elapsed since resuscitation, the conditions under which the event occurs, its mechanism (FV, TV, electromechanical dissociation, asystolia) and the clinical condition of the patient before cardiac arrest. Those situations where it is possible to promptly establish cardiorespiratory resuscitation (CRC) provide a greater chance of favourable development. However, the prognosis in intensive care units or other hospital wards is greatly influenced by the pre-existing clinical status of the patient.
Immediate prognosis is good for cardiac arrest occurring in intensive care units against the background of an acute cardiac event or a transient metabolic disorder, but for patients with chronic decompensated diseases or advanced extracardiac diseases (such as renal failure, pneumonia, septic state, diabetes, cancer) the prognosis is no better in the hospital than outside it. The success rate of initial resuscitation and survival after resuscitation in cardiac arrest outside hospital units depends largely on the mechanism of the event. When the mechanism is TV, evolution is good (67%), FV is next in order of success (25%) and asystolia and electromechanical dissociation have an unfavorable prognosis. Advanced age also negatively influences the chances of successful resuscitation.
Progression to biological death depends on the cardiac arrest mechanism and the time before intervention. FV or asystolia, without RCR in the first 4-6 minutes, has an unfavorable development and there are few survivors among patients who did not receive artificial support of vital functions in the first 8 minutes after onset. Statistics on evolution are improved by stabilisation interventions (life support) established before definitive ones (advanced life support - defibrillation) and early defibrillation.
Death during hospitalization after a successful cardiac arrest is closely related to the severity of the central nervous system damage. Anoxic encephalopathy and post-prolonged respiratory tract infections are 60% of the causes of death. Another 30% occur as a consequence of low heart rate states that do not respond to treatment. Paradoxically, recurrent arrhythmias are the rarest causes of death, causing only 10% of intra-hospital deaths.
In patients with cardiac arrest occurring at the onset of acute myocardial infarction (MI) it is important to distinguish between primary and secondary cardiac arrest. Primary cardiac arrest occurs in the absence of hemodynamic instability and secondary cardiac arrest occurs in patients with a clinically dominated ed abnormal hemodynamic picture before cardiac arrest. The rate of success of immediate resuscitation of primary cardiac arrest during an acute IM is estimated at 100%. In contrast, about 70% of patients with secondary cardiac arrest have death immediately or during the same hospitalization.
A major problem is the identification of patients at high risk for MSC, with primary cardiac arrest prophylaxis dependent on the ability to identify patients at high risk individually. The issue must be seen in the context of the total number of events and the population groups in which they occur. The annual incidence of MSC in an unselected adult population is 1-2 per 1000 individuals, clearly reflecting the prevalence of those patients with coronary heart disease where MSC is the first recognized clinical manifestation (20-25% of the first coronary events are MSC).
The incidence (% per year) increases progressively with the addition of coronary risk factors identified in populations without previous coronary events. The most important risk factors are age, high blood pressure, left ventricular hypertrophy (VS), smoking, high cholesterol serum levels, obesity and nonspecific cardiographic abnormalities. These coronary risk factors are not specific to MSC, but are still an increased risk factor for all coronary deaths.
The proportion of sudden coronary deaths remains at approximately 50% in all risk categories. Despite the relatively high risk of MSCs and multiple risk factors (from 1-2 to 1,000 individuals per year in an unselected population, to 50-60 to 1,000 in subgroups with multiple risk factors for coronary artery disease), the absolute incidence remains relatively low, viewed from the perspective of the relationship between the number of individuals who have had preventive interventions and the number of preventable events.
Specifically, 50% reductions in annual MSC risk would constitute a huge relative decrease, but intervention would be required for 200 unselected individuals to prevent sudden death. These figures highlight the importance of primary prophylaxis of coronary heart disease. Control of coronary risk factors is the only practical method of preventing MSC in large population segments, as long as most events occur in large unselected groups rather than in high-risk subgroups.
Among the high-risk factors, especially those related to recent major cardiovascular events (such as IM, recent onset of heart failure, survival after out-of-hospital cardiac arrest), the highest risk of sudden death occurs in the first 6-18 months and then decreases to the level of risk of the underlying disease. Thus, interventions are more effective when initiated early.
For patients with acute manifestations or a history of coronary artery disease, subgroups with an increased risk for MSC compared to the base population may be represented. The acute, convalescence and chronic phase of IM provide spare to large groups of high-risk population. The potential risk of cardiac arrest from onset and within the first 72 hours after acute IM (acute phase) may be 15-20%. The greatest risk of MSC in relation to IM is found in the subgroup presenting during the sustained TV or FV convalescence phase (from 3 days to 8 weeks).
A mortality of more than 50% in 6-12 months has been observed among these patients when treated conventionally, and at least half of these deaths are sudden. With advances in emergency response techniques (and increased access to them), the incidence has decreased impressively. After the acute phase of IM, the long-term risk for deaths in general and MSC is predicted by a number of factors.
The most important, for both MSC and non-MSC deaths, is the extent of myocardial damage caused during the acute event. This is illustrated by the degree of reduction of ejection fraction (FE), functional capacity and/ or the appearance of heart failure. The increasing frequency of CVP, with a plateau for the level of 10-30 CVP per hour in 24-hour outpatient monitoring, also indicates an increased risk, but advanced forms (unsupported TV in salvos) are the most important for prognosis.
CVP interacts strongly with the low ejection fraction (FE) of the left ventricle. The combination of frequent CVP, salvos or unsupported TV and an FE of less than 30% indicates patients with an annual risk of 20%. The risk decreases greatly with the reduction of CVP frequency and the absence of advanced forms, as well as with the increase of FE. Despite the implications for the risk of post-infarct CVP, no improvement in prognosis after CVP suppression has been demonstrated.
The severity of the underlying disease, determined by any cause and/ or clinical signs suggestive of the risk of MSC (i.e. survival after an out-of-hospital cardiac arrest not associated with acute IM) identifies patients at very high risk for a new (recurrent) cardiac arrest. Survival after an extra-hospital cardiac arrest is predictive for a heart rate of up to 30% in a year, in the absence of characteristic/specific interventions.
A general rule is that the risk of MSC is about half of the total cardiovascular mortality rate. Thus, the risk of MSC is about 20% per year for patients with advanced coronary heart disease or dilatative cardiomyopathy, severe enough to determine a total mortality rate of 40% in a year. Very high-risk subgroups include predictive population segments (percentages/year) for cardiac arrest or MSC, but the impact on the general population, indicated by the absolute number of preventable events, is considerably lower. The requirement to achieve a major impact on the population are effective prophylaxis of basic diseases and/ or new epidemiological data that would allow for more accurate identification of subgroups within the general population.
June 8th will come with the treatment approach, with which I will complete both the posts about collapse, shock and MSC as well as those about circulatory and respiratory disorders by starting a new "chapter" of the signs of the disease, that represented by gastrointestinal disorders (starting with dysphagia).
So, we've come to the presentation of the clinical characteristics of cardiac arrest and we're going to start with the prodrom, the onset, cardiac arrest and the exitus.
Sudden cardiac death (MSC) may be preceded by days, weeks or months of worsening angina, dyspnoea, palpitations, fatigue or other nonspecific symptoms. However, prodromal charges are generally predictive of any major cardiac risk, not specific to MSC.
The onset of the terminal event, leading to cardiac arrest, is defined as an acute change in cardiovascular status, preceding cardiac arrest by up to one hour. When the onset is brutal or instantaneous, the probability of the stop being of cardiac origin is greater than 95%. Continuous ECG records, made by chance at the onset of cardiac arrest, usually show changes in the heart's heart activity in the minutes or hours before the event.
There is a tendency to increase heart rate and the occurrence of advanced premature ventricular contractions (CVPs). Most cardiac arrests occurring through the ventricular fibrillation (Vf) mechanism begin with episodes of sustained or unsupported ventricular tachycardia (TV), which then degenerates into Vf. The sudden and unexpected decrease in actual circulation can be separated into "arrhythmic events" and "circulatory failure".
Arrhythmic events occur characteristically in patients in a waking state and active just before the event, have as a dominant electrical mechanism FV and a short duration of terminal state (less than one hour). In contrast, death from circulatory insufficiency occurs in inactive or comatose patients with a higher incidence of asystolia than FV, a tendency to a longer duration of terminal condition and cardiac events are dominant before the onset of terminal state.
The onset of cardiac arrest can be characterized by symptoms typical of an acute cardiac event, such as prolonged angina or onset pain from myocardial infarction, acute dyspnoea or ortopnea, palpitations, sustained tachycardia or sudden lye. However, many patients onset is precipitated without prodrom.
Cardiac arrest is by definition brutal. Thinking may be affected in patients with sustained TV during the installation of the terminal event. However, complete loss of consciousness is a sine qua non condition in cardiac arrest. Although spontaneous improvements rarely occur, cardiac arrest usually progresses to exitus within minutes (i.e. MSC occurs) if prompt intervention is not taken.
The success of the attempt to resuscitate the cardiac arrest patient is related to the time elapsed since resuscitation, the conditions under which the event occurs, its mechanism (FV, TV, electromechanical dissociation, asystolia) and the clinical condition of the patient before cardiac arrest. Those situations where it is possible to promptly establish cardiorespiratory resuscitation (CRC) provide a greater chance of favourable development. However, the prognosis in intensive care units or other hospital wards is greatly influenced by the pre-existing clinical status of the patient.
Immediate prognosis is good for cardiac arrest occurring in intensive care units against the background of an acute cardiac event or a transient metabolic disorder, but for patients with chronic decompensated diseases or advanced extracardiac diseases (such as renal failure, pneumonia, septic state, diabetes, cancer) the prognosis is no better in the hospital than outside it. The success rate of initial resuscitation and survival after resuscitation in cardiac arrest outside hospital units depends largely on the mechanism of the event. When the mechanism is TV, evolution is good (67%), FV is next in order of success (25%) and asystolia and electromechanical dissociation have an unfavorable prognosis. Advanced age also negatively influences the chances of successful resuscitation.
Progression to biological death depends on the cardiac arrest mechanism and the time before intervention. FV or asystolia, without RCR in the first 4-6 minutes, has an unfavorable development and there are few survivors among patients who did not receive artificial support of vital functions in the first 8 minutes after onset. Statistics on evolution are improved by stabilisation interventions (life support) established before definitive ones (advanced life support - defibrillation) and early defibrillation.
Death during hospitalization after a successful cardiac arrest is closely related to the severity of the central nervous system damage. Anoxic encephalopathy and post-prolonged respiratory tract infections are 60% of the causes of death. Another 30% occur as a consequence of low heart rate states that do not respond to treatment. Paradoxically, recurrent arrhythmias are the rarest causes of death, causing only 10% of intra-hospital deaths.
In patients with cardiac arrest occurring at the onset of acute myocardial infarction (MI) it is important to distinguish between primary and secondary cardiac arrest. Primary cardiac arrest occurs in the absence of hemodynamic instability and secondary cardiac arrest occurs in patients with a clinically dominated ed abnormal hemodynamic picture before cardiac arrest. The rate of success of immediate resuscitation of primary cardiac arrest during an acute IM is estimated at 100%. In contrast, about 70% of patients with secondary cardiac arrest have death immediately or during the same hospitalization.
A major problem is the identification of patients at high risk for MSC, with primary cardiac arrest prophylaxis dependent on the ability to identify patients at high risk individually. The issue must be seen in the context of the total number of events and the population groups in which they occur. The annual incidence of MSC in an unselected adult population is 1-2 per 1000 individuals, clearly reflecting the prevalence of those patients with coronary heart disease where MSC is the first recognized clinical manifestation (20-25% of the first coronary events are MSC).
The incidence (% per year) increases progressively with the addition of coronary risk factors identified in populations without previous coronary events. The most important risk factors are age, high blood pressure, left ventricular hypertrophy (VS), smoking, high cholesterol serum levels, obesity and nonspecific cardiographic abnormalities. These coronary risk factors are not specific to MSC, but are still an increased risk factor for all coronary deaths.
The proportion of sudden coronary deaths remains at approximately 50% in all risk categories. Despite the relatively high risk of MSCs and multiple risk factors (from 1-2 to 1,000 individuals per year in an unselected population, to 50-60 to 1,000 in subgroups with multiple risk factors for coronary artery disease), the absolute incidence remains relatively low, viewed from the perspective of the relationship between the number of individuals who have had preventive interventions and the number of preventable events.
Specifically, 50% reductions in annual MSC risk would constitute a huge relative decrease, but intervention would be required for 200 unselected individuals to prevent sudden death. These figures highlight the importance of primary prophylaxis of coronary heart disease. Control of coronary risk factors is the only practical method of preventing MSC in large population segments, as long as most events occur in large unselected groups rather than in high-risk subgroups.
Among the high-risk factors, especially those related to recent major cardiovascular events (such as IM, recent onset of heart failure, survival after out-of-hospital cardiac arrest), the highest risk of sudden death occurs in the first 6-18 months and then decreases to the level of risk of the underlying disease. Thus, interventions are more effective when initiated early.
For patients with acute manifestations or a history of coronary artery disease, subgroups with an increased risk for MSC compared to the base population may be represented. The acute, convalescence and chronic phase of IM provide spare to large groups of high-risk population. The potential risk of cardiac arrest from onset and within the first 72 hours after acute IM (acute phase) may be 15-20%. The greatest risk of MSC in relation to IM is found in the subgroup presenting during the sustained TV or FV convalescence phase (from 3 days to 8 weeks).
A mortality of more than 50% in 6-12 months has been observed among these patients when treated conventionally, and at least half of these deaths are sudden. With advances in emergency response techniques (and increased access to them), the incidence has decreased impressively. After the acute phase of IM, the long-term risk for deaths in general and MSC is predicted by a number of factors.
The most important, for both MSC and non-MSC deaths, is the extent of myocardial damage caused during the acute event. This is illustrated by the degree of reduction of ejection fraction (FE), functional capacity and/ or the appearance of heart failure. The increasing frequency of CVP, with a plateau for the level of 10-30 CVP per hour in 24-hour outpatient monitoring, also indicates an increased risk, but advanced forms (unsupported TV in salvos) are the most important for prognosis.
CVP interacts strongly with the low ejection fraction (FE) of the left ventricle. The combination of frequent CVP, salvos or unsupported TV and an FE of less than 30% indicates patients with an annual risk of 20%. The risk decreases greatly with the reduction of CVP frequency and the absence of advanced forms, as well as with the increase of FE. Despite the implications for the risk of post-infarct CVP, no improvement in prognosis after CVP suppression has been demonstrated.
The severity of the underlying disease, determined by any cause and/ or clinical signs suggestive of the risk of MSC (i.e. survival after an out-of-hospital cardiac arrest not associated with acute IM) identifies patients at very high risk for a new (recurrent) cardiac arrest. Survival after an extra-hospital cardiac arrest is predictive for a heart rate of up to 30% in a year, in the absence of characteristic/specific interventions.
A general rule is that the risk of MSC is about half of the total cardiovascular mortality rate. Thus, the risk of MSC is about 20% per year for patients with advanced coronary heart disease or dilatative cardiomyopathy, severe enough to determine a total mortality rate of 40% in a year. Very high-risk subgroups include predictive population segments (percentages/year) for cardiac arrest or MSC, but the impact on the general population, indicated by the absolute number of preventable events, is considerably lower. The requirement to achieve a major impact on the population are effective prophylaxis of basic diseases and/ or new epidemiological data that would allow for more accurate identification of subgroups within the general population.
June 8th will come with the treatment approach, with which I will complete both the posts about collapse, shock and MSC as well as those about circulatory and respiratory disorders by starting a new "chapter" of the signs of the disease, that represented by gastrointestinal disorders (starting with dysphagia).
Let us hear only good, let
us live as well as we can and let us not forget understanding,
love and gratitude (See, people!!!)!
Dorin, Merticaru