With regards to the causes and prevention of cardio-repiratory arrest?

Question

The risk of ventricular fibrillation after a MI is at the highest at the onset of the symptoms and decreases progressively over a number of hours Is this True or False

Answer 1

peedie,

With respect to the previous answerers, I'm not sure that it's quite that simple.

As with so many problems, the answer seems to be "It depends."

Generally speaking, the answer is True, but not always:

http://www.medscape.com/viewarticle/529299_4

"Ventricular arrhythmias are associated with an increased risk of death early after MI but not long-term. The concept that VA after MI alters short-term but not long-term mortality is controversial. Several studies, including the GISSI trial, the MILIS trial, and the Worcester Heart Attack Study, report that post-MI VAs have no influence on long-term survival"

Take a look at this site (you can only get a bit of the answer unless you subscribe, but you can see enough to begin to get an answer):

http://patients.uptodate.com/topic.asp?file=chd/14458

It summarizes with these words:

"RISK FACTORS — A number of clinical features have been evaluated as possible risk factors for the development of a fatal arrhythmia following an acute MI :

Reduced LV ejection fraction (LVEF)
Ventricular tachycardia (VT) induced by electrophysiologic study (EPS)
Spontaneous ventricular premature beats (VPBs) and nonsustained ventricular tachycardia (NSVT) documented on 24-hour ambulatory monitoring
Late potentials on a signal averaged ECG (SAECG)
Reduced heart rate variability (HRV) assessed by ambulatory monitoring
T wave (repolarization) alternans (TWA)"

Now, to further complicate matters, this site (I had trouble loading it, but it worked on the third try):

http://cmbi.bjmu.edu.cn/uptodate/coronary%20heart%20disease/Myocardial%20infarction/Ventricular%20arrhythmias%20after%20acute%20myocardial%20infarction-%20Incidence%20and%20clinical%20features.htm

Way down at the bottom of it was this note:

"There are no clinical features that reliably predict the patient at risk for experiencing VF in the periinfarction period. One report compared 57 patients with acute MI and VF to 1533 without this arrhythmia in an attempt to identify risk factors [25]. The patients with VF were:

• More likely to have a plasma potassium concentration below 4 meq/L (46 versus 10 percent)

• More likely to have atrial fibrillation (14 versus 4 percent)

• Less likely to have a non-Q wave MI (2 versus 19 percent)

An additional observation is that patients experiencing VF have QTc dispersion measured in the precordial leads that is greater when compared to patients not experiencing VF."

And, finally, an examination of the risk of VF after induced MI after exercise in dogs:

http://ajpheart.physiology.org/cgi/content/full/288/4/H1763

showed that animals with increased vagal tone showed less risk for VF.

So it would seem that the answer really is:

Yes, mostly, but not enough to be certain.

Answer 2

True

Death from a ventricular tachyarrhythmia in the setting of an acute myocardial infarction has historically been one of the most frequent causes of sudden cardiac death. As an example, 60 percent of all deaths associated with acute MI occur within the first hour and are attributable to a ventricular arrhythmia, in particular ventricular fibrillation . However, recent improvements in arrhythmia detection and treatment have had a major impact on the outcome of ventricular arrhythmias associated with acute MI. As a result, in-hospital mortality from arrhythmias has significantly decreased. Nevertheless, tachyarrhythmias remain a major cause of significant morbidity and mortality in the post-MI setting.

Answer 3

I even have eye floaters too. the only factor I even have discovered or learn (in Prevention magazine) to help decrease them is nutrition C. in case you will take 500 milligrams an afternoon for a week you could see some progression. Then possibly one hundred milligrams an afternoon. Floater are annoying to do away with, yet nutrition C does help. you could take C without area effects different than in the adventure that your physique gets greater advantageous than it desires you have an exceedingly elementary case of diarrhea. If this happens in basic terms decrease back on the C. Eye wash won't help floaters. there is not any prevention and now and back you will see greater after being sick from a chilly or flu. they frequently pass away by using themselves, yet do no longer consistently completely and it takes a mutually as though they finally do.

Answer 4

Semiautomatic external defibrillation: use inside a hospital]
[Article in Spanish]

* Moreno DA,
* Sagarzazu EE.

D.U.E. de Emergentziak-Osakidetza, Donostia.

The electric rhythm which provokes the majority of the cases of sudden death is ventricular fibrillation, and the only effective measure to reestablish spontaneous circulation consists in administering a precocious electrical discharge, or defibrillation. Time is a fundamental factor since the possibilities tor survival are practically nil it defibrillation is applied 10 to 12 minutes after the patient suffers his/her attack. Therefore, in recent years, the use of semiautomatic external defibrillators has been promoted. These small, low-cost, easy to handle apparatuses are designed so that the first person who detects a cardio-respiratory arrest can defibrillate, whether or not that person is a trained medical technician. Bearing in mind that in our hospitals nurses are in close contact with patients 24 hours a day nurses become the most appropriate professional to utilize these devices once they have received minimum training and instruction in the use of semiautomatic external defibrillators which will qualify and authorize nurses to do so.

Use of semi-automatic defibrillators outside the hospital]
[Article in French]

* Kacet S,
* Zghal N,
* Kouakam C,
* Benameur N,
* Goldstein P.

Service de cardiologie A, CHRU de Lille, boulevard du Pr-Leclercq, 59037 Lille.

With an annual incidence of 1 to 2@1000 and a rate of survival without complication of 2%, sudden death outside hospital constitutes a serious public health problem in France. Ventricular fibrillation (VF) is responsible for more than three quarters of these deaths. The rate of survival is inversely proportional to the duration of VF making early defibrillation a strong link in the chain of survival. The chances of survival are much greater if the cardio-respiratory arrest occurs with a witness, basic first aid is started rapidly, diagnosis of VF is made quickly and the first shock is delivered as soon as possible. These last two criteria are being met more often since the advent of the semi-automatic defibrillator (SAD) and its availability to first line rescuers. The SAD is a light and compact defibrillator capable of automatic analysis of the electrocardiographic trace, charging if it detects ventricular tachycardia (VT) or VF. By analysing the QRS amplitude, its slope, its morphology, its spectral density and the duration of the isoelectric line, the SAD is capable of recognising VF with a sensibility of 98% and a specificity of 93%. The shock, however, is only delivered with a manoeuvre from the operator. The SAD memorizes both the rhythmic event treated and certain parameters relating to its use. During the last decade, the SAD has benefited from the technological evolutions of the implantable automatic defibrillator, with the introduction of a biphasic shock. The use of a biphasic shock allows reduction in the minimal defibrillation charge and thus lightens the apparatus and increases the number of shocks which the SAD can deliver on a charged battery. In authorizing paramedics by statute to use the SAD, it has been possible to reduce the interval from alert to first delivered shock to 8 minutes although it would be 10 minutes if the medical team was awaited, and to obtain a survival rate without complication of 6.3%. The progress achieved by the use of the SAD in the chain of survival cannot be denied. However, to surpass automatic defibrillation and widen the use of defibrillators to an informed and motivated public would certainly bring our results closer to those obtained in America where the survival rate reaches 30% in the best cases; subject to widespread first aid training for the population.

An audit of cardiac arrest management by extended trained ambulance crew.

* Weston CF,
* Stephens MR.

Department of Cardiology, University Hospital of Wales, Cardiff, UK.

OBJECTIVE--To audit the use of extended skills by South Glamorgan Ambulance crew in attempted resuscitations from out-of-hospital cardio-respiratory arrest, in terms of successful discharge of patients from hospital and the accuracy with which agreed protocols were applied. Design-Retrospective analysis of ambulance report forms, electrocardiograph rhythm strips, casualty cards and discharge summaries during 26 months (1st May 1987-30th June 1989). SETTING--A mixed urban and semi-rural area of 187 square miles with a population of 396,000. RESULTS--There were 274 attempted resuscitations. Seven patients (2.5%) were managed for primary respiratory arrest and 3 were discharged. In 98 patients (35.8%) the initial resuscitation protocol was for ventricular fibrillation: 26 were admitted and 17 were discharged. In 169 patients (61.7%) the initial resuscitation protocol was for asystole or electromechanical dissociation: 11 were admitted and 1 discharged. The majority of patients who were successfully discharged from hospital were those in ventricular fibrillation who responded to defibrillation alone (13 survivors). Drug administration may have played a role in the successful resuscitation of the remainder. Endotracheal intubation was successful in 94.7% and vein cannulation in 87.7% of attempts. There were deviations from the ventricular fibrillation protocol in 27 cases (27.5%) and from the asystole protocol in 27 cases (16.0%). CONCLUSION--Survival rates for ventricular fibrillation managed by these personnel were satisfactory with early defibrillation. Defibrillation alone was responsible for the majority of successful resuscitations. The additional benefit of drug administration appears small, though potentially important. The majority of patients were in asystole by the time the ambulance arrived. IMPLICATIONS--Extended trained crews use their skills effectively. The most important skill is defibrillation. Further studies are required to explain the high proportion of patients found in asystole. The performance of individual ambulance personnel should be assessed prospectively, because agreed resuscitation protocols are not always followed.