Angiographic assessment of prospectively determined non-invasive reperfusion indices in acute myocardial infarction

Comparison of the prognostic role of Q waves and inverted T waves in the presenting ECG of STEMI patients

BACKGROUND

Both Q waves and T-wave inversion (TWI) in the presenting ECG are associated with a progressed stage of myocardial infarction, possibly with less potential for myocardial salvage with reperfusion therapy. Combining the diagnostic information from the Q- and T-wave analyses could improve the prognostic work-up in ST-elevation myocardial infarction (STEMI) patients.

METHODS

We sought to determine the prognostic impact of Q waves and TWI in the admission ECG on patient outcome in STEMI. We formed four groups according to the presence of Q waves and/or TWI (Q+TWI+; Q-TWI+; Q+TWI-; Q-TWI-). We studied 627 all-comers with STEMI derived from two patient cohorts.

RESULTS

The patients with Q+TWI+ had the highest and those with Q-TWI- the lowest 30-day and one-year mortality. One-year mortality was similar between Q-TWI+ and Q+TWI-. The survival analysis showed higher early mortality in Q+TWI- but the higher late mortality in Q-TWI+ compensated for the difference at 1 year. The highest peak troponin level was found in the patients with Q+TWI-.

CONCLUSION

Q waves and TWI predict adverse outcome, especially if both ECG features are present. Q waves and TWI predict similar one-year mortality. Extending the ECG analysis in STEMI patients to include both Q waves and TWI improves risk stratification.

Circadian Variation of the Efficacy of Thrombolytic Therapy in Acute Myocardial Infarction—Isn’t the Time Ripe for Cardiovascular Chronotherapy?

This study was designed to assess the circadian variation of the efficacy of thrombolytic therapy (TT) in 163 patients with acute myocardial infarction. Statistical analysis of the results suggests the existence of circadian variation in the efficacy of thrombolytic therapy with marked early morning resistance and significantly better late daytime results. There is a strong relationship between the normal physiologic rhythms of biochemical, hemodynamic, and hematologic parameters, observed in patients with CAD and the circadian fluctuations of efficacy of TT. Obviously the efficacy of TT is influenced by more evident impact of chronorisk factors during the early morning hours.

Idiopathic accelerated idioventricular rhythm or ventricular tachycardia originating from the right bundle branch: unusual type of ventricular arrhythmia

BACKGROUND

Accelerated idioventricular rhythm (AIVR) or ventricular tachycardia (VT) originating from the right bundle branch (RBB) is rare and published clinical data on such arrhythmia are scarce. In this study, we will describe the clinical manifestations, diagnosis, and management of a cohort of patients with this novel arrhythmia.

METHODS AND RESULTS

Eight patients (5 men; median age, 25 years) with RBB-AIVR/VT were consecutively enrolled in the study. Pharmacological testing, exercise treadmill testing, electrophysiological study, and catheter ablation were performed in the study patients, and ECG features were characterized. All RBB-AIVR/VTs were of typical left bundle-branch block morphology with atrioventricular dissociation. The arrhythmias, which demonstrated chronotropic variability, were often isorhythmic with sinus rhythm and were accelerated by physical exercise, stress, and intravenous isoprenaline infusion. The rate of RBB-AIVR/VT varied from 45 to 200 beats per minute. Two patients experienced syncope, and 3 had impaired left ventricular function. Metoprolol was proven to be the most effective drug to decelerate the arrhythmia rate and relieve symptoms. Electrophysiology study was performed in 5 patients and the earliest activation with a sharp RBB potential was localized in the mid or distal RBB area. Catheter ablation terminated the arrhythmia with subsequent RBB block morphology during sinus rhythm. During follow-up, patients' symptoms were controlled with normalization of left ventricular function either on metoprolol or by catheter ablation.

CONCLUSIONS

RBB-AIVR/VT is an unusual type of ventricular arrhythmia. It can result in significant symptoms and depressed ventricular function and can be successfully treated with catheter ablation.

Usefulness of peak systolic strain measurement by automated function imaging in the prediction of coronary perfusion in patients with acute myocardial infarction

BACKGROUND/AIMS

The usefulness of global longitudinal peak systolic strain (GLPSS) measurement by automated function imaging (AFI) in the prediction of perfusion status of infarct-related artery (IRA) before percutaneous coronary intervention (PCI) was evaluated.

METHODS

Sixty-nine patients with acute myocardial infarction (AMI) who underwent successful primary PCI were divided into two groups; the patients with occlusion of IRA (Group I, 41 patients, 63.0 ± 14.9 years of age, 31 males) versus the patients with patent IRA (Group II, 28 patients, 63.8 ± 11.2 years of age, 15 males). GLPSS by AFI and wall-motion score index (WMSI) were analyzed in both groups.

RESULTS

GLPSS was significantly decreased in Group I compared with Group II (-11.2 ± 3.7 vs. -14.1 ± 4.7%, p = 0.005), but WMSI (1.49 ± 0.28 vs. 1.35 ± 0.32, p = 0.062) did not differ between groups. GLPSS of infarct segments was significantly lower (-3.7 ± 5.4 vs. -11.4 ± 4.8%, p < 0.001), and WMSI of infarct segments was significantly higher (2.13 ± 0.57 vs. 1.66 ± 0.57, p = 0.001) in Group I compared with Group II. By receiver operation curve analysis, the area under the curve to predict IRA occlusion was 0.850 in GLPSS of infarct segments and 0.719 in WMSI of infarct segments. The optimal cut-off value to predict IRA occlusion was -9.4% in GLPSS of infarct segments (sensitivity, 85.4%; specificity, 67.9%) and 1.68 in WMSI of infarct segments (sensitivity, 78.0%; specificity, 60.7%).

CONCLUSIONS

The present study suggested that GLPSS measured by AFI is a more sensitive predictor of IRA occlusion than is WMSI before PCI. Routine measurement of GLPSS by AFI can be a very useful tool in risk stratification of AMI.

Frequent accelerated idioventricular rhythm in a young male of Buerger's disease with acute myocardial infarction

Buerger's disease is a small and medium vessel vasculitis that predominantly involves the distal extremities. Coronary involvement is rarely reported. We reported a 32 year-old man with Buerger's disease (thromboangiitis obliterans) suffering from acute anterior chest pain and V(1-6) ST-segment elevation. Frequent episodes of accelerated idioventricular rhythm (AIVR) were found during initial admission. Emergent coronary angiography revealed thrombus inside the proximal left anterior descending coronary artery and primary percutaneous trasluminal coronary angioplasty and stenting was successfully done after thrombus aspiration. No more AIVR occurred after the procedure. Doctor should be alerted to AIVR as a sign of reperfusion in the acute coronary syndrome even in a young subject.

Low levels of plasma soluble complement receptor type 1 in patients receiving thrombolytic therapy for acute myocardial infarction

BACKGROUND

Administration of recombinant soluble CR1 (sCR1) has been shown to attenuate complement mediated myocardial injury in animal models of acute MI. The plasma level of sCR1 in humans with acute MI is not known. We determined the levels of the complement regulatory protein, complement receptor type-1 (CR1) in plasma and its expression on the surface of leukocytes of patients receiving thrombolysis for acute myocardial infarction (AMI).

METHODS

Plasma sCR1 was measured by a sandwich ELISA. The levels in patients with AMI were compared with those in normal controls. Leukocyte surface expression of CR1 was measured by flow cytometry. We correlated these parameters with clinical outcome and left ventricular ejection fraction.

RESULTS

Patients had very low plasma sCR1 levels. Mean plasma sCR1 levels were significantly less than in controls (6 +/- 3.6 ng/mL vs. 44.6 +/- 12.2 ng/mL, P < 0.00001). Patients who had an adverse in-hospital outcome had significantly lower sCR1 levels when compared to those who had an uneventful course (3.8 +/- 2.0 ng/mL and 7.1 +/- 3.8 ng/mL respectively, P = 0.01). The low plasma sCR1 was despite significantly greater lymphocyte and monocyte surface CR1 (which is a potential source of plasma sCR1).

CONCLUSION

Plasma sCR1 levels are reduced in patients receiving thrombolysis for AMI. Replenishing plasma sCR1 might limit complement-mediated injury in this setting.

Electrocardiographic Markers of Reperfusion in ST-elevation Myocardial Infarction

The outcome of patients who fail to reperfuse with thrombolytic therapy or percutaneous coronary intervention (PCI) for ST-elevation acute myocardial infarction (STEMI) may be improved with additional pharmacologic and mechanical interventions such as rescue PCI or intravenous glycoprotein IIb/IIIa infusion. The standard 12-lead ECG is the most commonly available and suitable tool for routine bedside evaluation of the success of reperfusion therapy for STEMI. This article reviews and discusses the current data on the four ECG markers for prediction of the perfusion status of the ischemic myocardium: ST-segment deviation, T-wave configuration, QRS changes, and reperfusion arrhythmias.

Accelerated idioventricular rhythm in the post-thrombolytic era: incidence, prognostic implications, and modulating mechanisms after direct percutaneous coronary intervention

BACKGROUND

In the thrombolytic era, the occurrence of accelerated idioventricular rhythm (AIR) has been proposed to be a specific marker for successful reperfusion. The incidence, prognostic implications, and potential modulating mechanisms of AIR after successful restoration of antegrade flow by means of modern reperfusion therapy (i.e., direct percutaneous coronary intervention (PCI)) has thus far not been investigated.

METHODS

We prospectively investigated 125 consecutive patients undergoing direct PCI for a first acute myocardial infarction (AMI). The incidence of AIR was determined from 24-hour Holter monitoring, initiated prior to PCI.

RESULTS

AIR appeared in 19 patients (15.2%). There were no significant differences between patients with or without AIR regarding baseline clinical characteristics. The incidence of AIR was not different between patients with TIMI 2 and 3 flow (13% vs 16%). There were no differences in the incidence of major cardiac events within 12-month follow-up in patients with and without AIR. Patients with AIR exhibited higher mean R-R intervals (mean 24-hour R-R interval: 871.3 +/- 121 vs 796.4 +/- 100 ms, P < 0.01), higher hourly mean values of heart rate variability (SDNN, 64.7 +/- 26 vs 49.4 +/- 20 ms, P < 0.01; rMSSD, 29.3 +/- 15 vs 22.0 +/- 12 ms, P < 0.01) and lower serum norepinephrine concentrations (60 minute after PCI, 478.9 +/- 357 vs 649.0 +/- 499 pg/ml, P < 0.05).

CONCLUSIONS

Our findings indicate that AIR is an nonspecific marker for reperfusion of the infarct-related artery in AMI and thus, predate previous observations of the thrombolytic era. Even though, AIR was associated with higher tonic vagal tone and lower sympathetic activity, the occurrence of AIR had no prognostic impact on the clinical course and was not able to discriminate between complete and incomplete reperfusion.

Usefulness of frequent arrhythmias after epicardial recanalization in anterior wall acute myocardial infarction as a marker of cellular injury leading to poor recovery of left ventricular function

Ventricular arrhythmias are associated with epicardial reperfusion but may also be a sign of cellular injury, which affects recovery of left ventricular (LV) function. To assess the correlation between reperfusion arrhythmias and the change in LV function after the acute phase in reperfused acute myocardial infarction (AMI), 62 patients with reperfused anterior wall AMI were studied. All patients underwent 24-hour Holter recording, echocardiography, and coronary angiography during the acute phase of AMI. Echocardiography was repeated at 1 to 2 months after AMI. Correlations between ventricular arrhythmias in the reperfusion phase and the change in LV wall motion score (WMS) during follow-up were studied. The number of reperfusion arrhythmias was significantly higher in patients with further deterioration of LV function; there were 5-, 14-, 131-, and 11-fold increases in isolated premature ventricular complexes (PVCs), PVCs in couplets, PVCs in bigeminy, and total PVCs, respectively, in patients with further increases in WMS after the acute phase. The incidence of repetitive, frequent, and early accelerated idioventricular rhythms (AIVRs) was correlated significantly with the change in LV function, with 129- and 105-fold increases in numbers of early AIVRs and total AIVRs, respectively, in patients with further worsening of LV function during follow-up. The incidence and the number of long-lasting nonsustained ventricular tachycardias as well as the number of rapid ventricular tachycardias and total ventricular tachycardia episodes were also correlated significantly with further deterioration. Thus, frequent arrhythmias associated with epicardial reperfusion strongly correlate with further worsening of LV function after the acute phase of AMI. This supports the hypothesis that these reperfusion arrhythmias are probably a noninvasive marker of cellular injury.

Systematic coronary stenting after failed thrombolysis in high-risk patients with acute myocardial infarction: procedural results and long-term follow-up

BACKGROUND

Stenting in acute myocardial infarction (AMI) represents a feasible and effective revascularization strategy. However, very little information is available for patients who receive a stent after failed thrombolysis (so-called 'rescue' stenting).

METHODS

We analysed the procedural results and the 2-year follow-up of all consecutive patients with moderate-to-large AMI treated with rescue stenting in the period 1996-2001.

RESULTS

The study cohort includes 123 patients (mean age 60+/-12 years, 78% men). Coronary angiography showed multivessel disease in 47% of patients; the infarct-related vessel was the left anterior descending coronary artery in 47%, the right coronary artery in 41%, the left circumflex coronary artery in 9.5% and a saphenous vein graft in 2.5%. Baseline Thrombolysis in Myocardial Infarction (TIMI) flow was grade 0-1 in 65% and grade 2 in 25%. Coronary stenting was attempted in all 123 patients and was successful in 119 out of 123 (96.7%); abciximab was used in 57 out of 123 (46%) and intra-aortic balloon pumping in 35 out of 123 (28%). At the end of the procedure, TIMI 3 flow was obtained in 104 out of 123 (85%) and TIMI 2 flow in 14 out of 123 (11%). There were 10 in-hospital deaths and four late deaths, with a long-term survival of 88.6%. This figure increases to 95.2% if patients presenting with cardiogenic shock are excluded. A new revascularization procedure was performed in 21% of discharged patients (in the target vessel for 12% and in non-target vessels for 9%). Overall, event-free survival at 2 years was 69%. At multivariate analysis, independent predictors of survival were age (P=0.014) and ejection fraction (P=0.006).

CONCLUSIONS

This report represents one of the first series concerning long-term follow-up after rescue stenting. The main results include a high procedural feasibility, a low late mortality and a target vessel revascularization rate in the range expected with stenting. These data must be viewed as part of the constant effort to optimize revascularization strategies in AMI.

Impact of diabetes mellitus on epicardial and microvascular flow after fibrinolytic therapy

BACKGROUND

Patients with diabetes are at increased risk of death after acute myocardial infarction, independent of other baseline risk factors and more severe coronary artery disease. We studied the angiographic and electrocardiographic responses to thrombolytic agents in patients with diabetes; in particular ST-segment resolution as a measure of microvascular flow.

METHODS

Angiography was performed in 2588 patients at 90 minutes after thrombolytic agent administration as well as after percutaneous coronary intervention (PCI) in the Thrombolysis In Myocardial Infarction (TIMI) 4, 10A, 10B, and 14 trials. Electrocardiographic parameters were assessed at baseline and at 90 minutes in the TIMI 14 trial.

RESULTS

Compared with those without diabetes, patients with diabetes (347/2588 [13.4%]) were older, more often female, heavier, and less often smokers, and they had higher systolic blood pressure on admission. At angiography, they more frequently had 3-vessel disease, well-developed collateral vessels, more distal culprit lesions, and smaller reference segment diameters. In the infarct-related artery, there was no relationship between diabetes and TIMI 3 flow at 90 minutes (55.4% vs 59.0% without diabetes) or after PCI, (83.7% vs 84.2%, both P = NS). Corrected TIMI frame counts were also similar at both time points. However, there was less frequent complete ST-segment resolution among diabetic patients after thrombolysis (38.6% vs 49.2%, adjusted P =.04).

CONCLUSION

Thrombolysis and adjunctive/rescue PCI achieved equal rates of epicardial flow in patients with and without diabetes. However, diabetic patients had less complete ST-segment resolution, suggesting impaired microvascular flow. Abnormal microvascular flow may contribute at least in part to the poorer outcomes observed in patients with diabetes and acute myocardial infarction.

ST segment resolution as a tool for assessing the efficacy of reperfusion therapy

Rapid, simple and inexpensive measures are needed to assess the efficacy of reperfusion therapy both in clinical practice and in clinical trials testing novel reperfusion regimens. In the last decade, several observations have led to a favorable reappraisal of the utility of ST segment monitoring as a simple means of assessing reperfusion in patients receiving fibrinolytic therapy for acute ST elevation myocardial infarction, and ST resolution is being used increasingly in clinical practice and in clinical research. This review focuses on four interrelated roles for ST segment monitoring: the assessment of epicardial reperfusion and the identification of candidates for rescue percutaneous coronary intervention; the evaluation of microvascular and tissue-level reperfusion; the determination of prognosis early after fibrinolytic therapy; and the use of ST segment resolution to compare different reperfusion regimens.