After ICI discharge daily ECG or predischarge (Jansen et al., 1986; Evrard et al., 2000) Holter monitoring was used to detect arrhythmias. In some cases the monitoring may be continued beyond the hospital stay for 30 (Guarnieri et al., 1999) up to 90 days (Weber et al., 1990). The use of the Holter monitor makes extended monitoring more feasible than when ECG was the only option.
Several anomalies have been found to act as indicators that AF may occur. For instance, prolonged P-wave duration was found to be an indicator of reoccurring AF (Gialiafos, 1999; Steinberg et al., 1993). Patients with a clinical history of AF were found to have a significantly longer intra-atrial and inter-atrial conduction time of sinus impulses (Centurion et al., 2002). The presence of preoperative supraventricular arrhythmias and fluctuations in autonomic balance were identified in some, but not all studies as a risk factor for post operative AF (Jideus et al., 2000).
There are still too many gaps in knowledge about the mechanism of post operative AF to make a prediction about the likelihood of any particular patient outcome. Monitoring techniques have revealed several indicators that the patient may be at an increased risk for developing AF. However, there is still no definitive consensus as to the electrocardiographic characteristics that predict the development of post operative AF (Terranova et al., 2007). Monitoring typically ends when the person leaves the hospital. However, the use of Holter monitoring provides the ability to extend the monitoring period.
The goal of monitoring and study of the mechanisms behind post operative AF is to reduce the risk of patients that undergo any type of heart surgery. It is not enough to identify risk factors. Current monitoring techniques that are intermittent after the release of the patient from ICU may miss several important indicators that AF may occur at some time in the future. The development of practices to eliminate post operative AF are not as advanced as for other post operative complications. The development of better management practices through prevention depends on developing a better understanding through study of the mechanism that drives AF.
The development of better preventative measures depends on the ability to recognize the precursors of an episode. Several types of arrhythmias can occur during percutaneous coronary interventions (PCI). Many of these arrhythmias may result from catheter manipulation, dye injection, reperfuson injury and other disturbances of the heart tissue (Terranova et al., 2007). Any action that disturbs the atrial tissue can cause an AF event. Stretching due to atrial swelling, or stretching in heart failure can also cause AF (Terranova et al., 2007). Management of atrial fibrillation includes prevention of these factors that can cause the initiation of AF. Recent studies are beginning to shed light on the electrophysiological factors that can indicate that AF is about to occur. They are also attempting to spend more time studying the mechanism that drives the initiation of AF and the mechanism that allows it to keep going.
Budeus et al. (2003) studied the incidence of atrial late potentials in patients that also had a proximal stenosis of the right coronary artery. They found that when this condition was treated with percutaneous translunminal coronary angioplasty (PTCA) the atrial later potentials were also gone. In this study atrial fibrillation was associated with stenosis of the right coronary artery. In this case, reduction of pre-existing atrial late potentials may also reduce the incidence of atrial fibrillation later.
Another study found the PTCA on patients with acute anterior wall MI reduced the risk factors of AF by decreasing P-wave durations (Akdemir et al., 2005). Gorenek and associates (2000) found that patients that developed AF during acute MI and underwent primary PCI also returned to normal sinus rhythm. However, they also discovered that those who underwent thrombolytic therapy developed AF within 12 hours of hospitalization. It was found that the most frequent cause of AF was right coronary artery occlusion (Gorenek et al., 2000).
These studies highlight the fact that AF is treated as a secondary condition. It is treated viewed as a complication of another condition rather than a condition of its own merit. In several studies, we found that it resolved as a secondary effect of treatment for another condition. More importantly, it can be brought on by an intervention to treat another condition. AF is a serious condition that can lead to death and needs to be treated as a primary concern in many cases. It is not known why the medical community has chosen to treat AF as a secondary condition rather than a primary one. However, there is clear evidence that this attitude must change. More attention needs to be focused on predicting AF and preventing it. AF is difficult to treat once it gets started. Therefore, the focus needs to be on predicting and preventing this serious condition.
Electrical cardioversion is often used when AF cannot be controlled by other means (Terranova et al., 2007). A beta-blocker is used for rate control. Other drugs such as esmolol, verapamil, or diltiazem may also be used to help bring AF under control. However, these must be used with caution as other conditions, such as pulmonary congestion could make them dangerous. Dofetelide, amiodarone and digoxin are also possibilities to control AF under various circumstances (Terranova et al., 2007). The author notes that in many cases AF tends to revert to normal rhythm spontaneously, but if it does not do so immediately, then treatment of some type should be given. The longer AF continues, the harder it is to stop.
Post operative AF is a common complication of coronary artery bypass surgery (CABG). The incidence of this complication is typically higher during the first week after the operation (Terranova et al., 2007). However, it was found that the incidence of AF as a complication of CABG was greater when Holter monitoring was used as opposed to trials without. This has serious implications for the discovery and treatment of post operative AF. It implies that better monitoring means increased likelihood of catching AF before it becomes a problem. It also implies that infrequent monitoring may miss some of the early warning signs of AF. This would lead to the conclusion that Holter monitoring is the preferred method for monitoring and preventing AF during the postoperative period.
Regardless of improvements in monitoring techniques and post operative patient care incidences of post operative AF are in the increase (Terranova et al., 2007). This can be explained by and increasing elderly population and of patients that have other underlying conditions (Terranova et al., 2007). AF is considered to be non-life threatening in many cases. However, it significantly increases the incidence of subjective symptoms including congestive heart failure, hypotension, and swelling of the tissues (Terranova et al., 2007).
Stroke is a major event that is often associated with AF (Terranova et al., 2007). AF was found to be a major factor predicting stroke after a CABG procedure. AF preceded neurological events in nearly 27% of patients in one study (Terranova et al., 2007). AF is also associated with greater in hospital mortality (Terranova et al., 2007). This included short-term survival and long-term survival of 3-5 years. AF is an important signal for more serious conditions in many cases. AF is a symptom that heralds many more serious events. This would indicate the need for increased continuous monitoring, rather than the intermittent monitoring that is used once patients leave the ICU. Many more complicated conditions could be prevented by watching for the presence of AF, rather than waiting for the big event to occur.
Studies have identified many comorbidities associated with AF. The presence of these conditions should indicate the need for closer monitoring than is typically undertaken. AF indicates an imbalance in the autonomic nervous system, including increased circulation norepinephrine in older patients (Terranova et al., 2007). However, the author notes that thoracic epidural anesthesia was not effective in preventing post operative AF, as would be expected if autonomic nervous system were the only cause of the condition.
AF increases the health care expenditure of many procedures by increasing the amount of time spent in the hospital. It can be a warning sign of many more serious conditions. Although it is typically treated as non-threatening, it can be dangerous in its own right. AF is potentially reversible with a few common sense actions. For instance, the literature suggests a number of prophylactic measures. New post operative antiarhythmic therapies are being developed including sotalol and amiodrone (Terranova et al., 2007). It might be noted that treating AF with these drugs did not reduce the risk of stroke. Instead the treatment caused the patient to be released earlier, when this may not have been the wisest idea. These drug therapies are important in the control of episodes of dangerous AF. However, controlling mild cases of AF may also mask an important warning sign of a more serious condition.…