Reperfusion patterns

If this pattern (very deep negative T wave from V1-V4-V5) appears after reperfusion (fibrinolysis or PCI) treatment in a patient with STE-ACS, it is considered as a sign that the treatment of revascularisation has been effective (reperfusion pattern). In these cases there is usually no need for PCI, although the patients have to be carefully watched because on some occasion a new coronary event may evolve, if for instance an intrastent thrombosis appears (Figure 8.9). 

The ECG pattern of subepicardial ischaemia -flattened or negative T wave - is observed in IHD (Table 2.1), but it may also appear in other situations (see Table 3.2). We have to remember that the ECG pattern of subepicardial ischaemia (negative T wave) although may probably be due to real active ischaemia (ACS), more often appear in the dynamic changes of some ACS as a reperfusion pattern or is explained by the changes that MI has induced in ventricular repolarisation (chronic Q-wave MI) (p. 37 and Table 8.1). 

Both the clinical ST-segment depression pattern and the experimental subendocardial injury pattern have a common explanation the sum of subendocardium TAP, which is of worse quality than in the subepicardium (Figure 4.5), or the generation of an injury vector (Figure 4.8). In NSTE-ACS the presence of new ST-segment depression is related with the presence of evident active ischaemia predominantly in the subendocardium. On the other hand, the presence of flat or negative T wave is related with previous ischaemia (often is a reperfusion pattern) without subendocardial predominance (Table 2.1 and Figure 3.9). 

Figure 8.3 Atypical patterns of STE-ACS. (A) Tall and positive T wave in V1-V2. Hyperacute phase of LAD occlusion. (B) Deep and negative T wave in V1-V4-V5. Impending STE-ACS or reperfusion pattern after treatment. New occlusion may appear. (C) ST-segment depression in V1-V2 clearly greater than ST-segment elevation in inferior/lateral leads due to LCX occlusion.

Figure 8.9 (A) A patient with ACS with ST-segment elevation with the pattern found in cases of severe transmural ischaemia (increase in R( disappearance of S wave, ratio J point/R wave >0.5). Troponin levels were normal. (B) The ECG after primary PCI of proximal LAD presents a deep negative T wave from V2-V4, suggestive of opened artery (reperfusion pattern).

From the electrocardiographic standpoint a pattern of STE-ACS is usually evident, which evolves towards a deep negative T wave with the morphological characteristics of opened artery, which we have described previously (reperfusion pattern) (see p. 38). This pattern is accompanied by a transient Q wave (QS morphology) (Figure 8.42). These changes especially seen in precordial leads occur concomitantly with a transient lengthening... 

The coronary spasm may be present in any of the three epicardial arteries and the duration ranges from seconds to a few minutes (Figure 8.10). During the crisis sometimes a transient Q wave appears. Figure 8.45 shows a case of very striking coronary spasm of proximal LAD that is followed by very deep negative T wave in all precordial leads with Q wave in V1-V2 but without increase of enzymes (reperfusion pattern). After few days, the ECG normalises (see Figure 8.45C). 

The fourth group is those who present to the emergency department at any time after the onset of chest pain with clear ECG evidence of AMI. In this group, detection with serum biomarkers of myocardial injury is not necessary initially. Many of these patients may qualify for reperfusion therapy at a time before blood markers of cardiac injury have increased, and therapy should not be withheld if these criteria are met. Subsequently, specific and sensitive myocardial markers could be employed to monitor the success of reperfusion during the 60- to 90-minute period after therapy. Rapid assays providing early serial values followed by interpretation of the markers patterns of appearance are often helpful in determining subsequent management. 

Coronary flow fractions (CFF) were collected and analyzed using previously published procedures (see Methods and refs. [10,11]). The first CFFs of reperfusion contained relatively high levels of iron and copper (Table 2). The values were dependent on the duration of ischemia, while the concentrations of group I CFFs were systematically and markedly lower (by a factor of 2-5) than the corresponding values of group III. The mobilization patterns of these metals from the tissue to the CFF were similar to each other, but distinctly different for iron, copper, and protein, indicating that this mobilization does not reflect a simple necrotic process, but rather a selective one [11]. 

Deep negative T wave in precordials (VI-V2 to V4-V5) as an atypical pattern of STE-ACS It corresponds to a critical proximal subocclusion of the LAD that has been spontaneously, and partially, reperfused or even complete LAD occlusion but with great number of collaterals (De Zwan, Bar and Wellens, 1982) (Figures 3.9B(2) and 3.21, and Table 8.1). This is an ECG dynamic pattern that may evolve without treatment to STE-ACS, with homogeneous and global cardiac wall involvement. In this case, the T wave... 

On the other hand, at times, especially in the presence of multivessel coronary disease, negative, flattened or very low voltage positive T waves may be recorded in various leads due to delay in repolarization without subendocardial predominance that is usually consequence of post-ischaemic changes (reperfusion) (see p. 32, Figures 3.22 and 3.23). The differential diagnosis of this pattern from the ECG pattern found in some cases of pericarditis may be... 

Figure 5.9 Correlations between the different myocardial infarction (Ml) types with their infarction area assessed by contrast-enhanced (CE) CMR, ECG pattern, name given to the infarction and the most probable place of coronary artery occlusion. Due to frequent reperfusion treatment...

Wellens syndrome) (De Zwane, Bar and Wellens, 1982) (seep. 42). Also, a similar pattern may be seen in STE-ACS after reperfusion (fibrinolysis or PCI), as it is a good sign of opened artery (see p. 220). 

We consider that ACS with deep negative T wave in V1-V4, as mentioned before (p. 212), is an atypical pattern of STE-ACS that usually does not imply an emergency because this ECG represents that probably the artery is at least partially open. The urgency depends on the clinical picture (repetitive pain) and on ECG dynamic changes. However, in all these cases, a coronary angiography has to be performed as soon as possible. Obviously, this ECG pattern when seen after reperfusion treatment represents a good marker of open artery (p. 230). 

Before the era of reperfusion with fibrinolytics or PCI it was relatively easy to predict the final Q-wave infarction pattern according to the acute phase STE-ACS. Aldrich et al. (1988) described a score (see p. 224) for estimation of the extent of myocardium at risk of infarction in the absence of reperfusion therapy. However, currently with the new strategies of treatment, this is impossible because if the treatment is started on time, the infarction may be aborted (Figure 8.2) or at least decreased. 

Sometimes the abnormality of repolarisation is an isolated negative or flattened T wave. These patterns are probably more related with partial or total reperfusion than with active ischaemia. This may be an explanation of the best prognosis having non-Q-wave MI with negative T wave (p. 239). Furthermore, often the levels of troponine are decisive to assure that an ACS has evolved to an MI because the ECG pattern may not give the correct answer (see Figure 8.2, and Tables 2.1 and 8.1). 

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