Significance of Q wave disappearance in the chronic phase following transmural acute myocardial infarction

Transient Q-waves in an infant with asymptomatic myocardial infarction due to Kawasaki disease

Giant coronary artery aneurysms are a complication of Kawasaki disease and can be fatal if associated with thrombosis. We describe the clinical outcome of a boy with Kawasaki disease who exhibited "supergiant" coronary artery aneurysms at the age of 14 months and, despite treatment with anticoagulant and antiplatelet medication, developed a left coronary artery thrombosis and presented following a myocardial infarction at 2 years old. Although his symptoms were minimal, the myocardial infarction was identified by abnormal Q-waves and giant negative T-waves in precordial leads of routine electrocardiography. Intensive anticoagulant therapy combining heparin injections and high-dose warfarin was successful. The abnormal Q-waves and negative T-waves had completely disappeared 2 weeks later, likely in association with confirmed reperfusion. On the basis of prompt identification of abnormal Q-waves by electrocardiography, the patient could avoid thrombolytic therapy and catheter or surgical intervention.

Fragmented QRS on surface electrocardiogram is not a reliable predictor of myocardial scar, angiographic coronary disease or long term adverse outcomes

PURPOSE

Conflicting evidence remains regarding the value of fragmented QRS (fQRS) on surface electrocardiogram (EKG). We present the 5-year outcome of patients with fQRS on EKG and its correlation to SPECT and coronary angiography (CA).

METHODS

We retrospectively studied EKG's in 248 consecutive patients undergoing SPECT and CA with known or suspected coronary artery disease (CAD). The presence of fQRS or Q waves in two contiguous EKG leads was correlated with major coronary artery distributions on SPECT and cath. Patients with bundle-branch block, paced-rhythm or absence of EKG within one month of SPECT were excluded. The final EKG data for 238 patients were analyzed and compared with myocardial scar on SPECT and the presence of significant (>50%) coronary stenosis on CA. Predictors of MACE (death, MI, heart failure) were evaluated. Freedom from all-cause mortality was assessed by Kaplan-Meier analysis.

RESULTS

Of 238 patients, no significant difference was noted in the presence of scar on SPECT in fQRS (3/77; 3.8%) versus no fQRS (11/161; 6.8%) (P=0.56); or CA based CAD (55/77; 71% fQRS) and no fQRS (99/161, 61.4%) (P=0.20). EKG Q wave presence was similar in both groups: (12/77; 15.5% fQRS), (17/161; 10.5% no fQRS) (P=0.3). Patients with CA based significant LAD disease were 3.680 times more likely to have fQRS (P=0.04), however, fQRS was not significantly associated with MACE (P=0.92) or all-cause mortality (P=0.93).

CONCLUSIONS

This study does not support routine assessment of fQRS on surface EKG as a reliable predictor of SPECT myocardial scar, MACE or all-cause mortality over a long period of follow-up.

The assessment of relationship between fragmented QRS complex and left ventricular wall motion score index in patients with ST elevation myocardial infarction who underwent primary percutaneous coronary intervention

OBJECTIVES

Fragmented QRS (fQRS) has been found to be associated with high mortality and arrhythmic events in acute coronary syndromes. Regional systolic function using wall motion score index (WMSI) is an alternative to left ventricular ejection fraction (LVEF) for the assessment of left ventricular systolic function. The aim of this study was to investigate the relation between the presence of fQRS on admission electrocardiogram (ECG) and WMSI in ST elevation myocardial infarction (STEMI) underwent primary coronary intervention (PCI). The in-hospital and long-term prognostic significance of persistent fQRS was also evaluated.

METHODS

In this retrospective study, 542 patients with a diagnose of STEMI underwent primary PCI were included. Study patients were divided into two groups according to the presence (n = 153) or absence (n = 389) of a fQRS on admission ECG.

RESULTS

WMSI was found to be significantly higher in fQRS(+) group compared to the fQRS(-) group (P < 0.001). In multivariete analysis, WMSI was found to be an independent predictor of fQRS, and fQRS was inversely associated with LVEF. The in-hospital reinfarction (P = 0.003), MACE (P = 0.024), intraaortic balloon pump use (P = 0.014), and advanced heart failure (P < 0.001) were found to be significantly more frequent in the fQRS(+) group. The presence of fQRS on admission was found to be associated with an increase in long-term cardiovascular mortality (P = 0.028), and long-term all-cause mortality (P = 0.022).

CONCLUSION

WMSI was significantly related with the presence of the fQRS, which reflects the linking between impairment of regional left ventricular systolic function and the presence of severe myocardial injury in STEMI.

Significance and usefulness of narrow fragmented QRS complex on 12-lead electrocardiogram in acute ST-segment elevation myocardial infarction for prediction of early mortality and morbidity

BACKGROUND

The presence of notched R or S waves without accompanying typical bundle branch blocks, or the existence of an additional wave like RSR' pattern in the original QRS complex (with a duration of <120 ms) has been defined as narrow QRS fragmentation. Persistence of the fQRS found on the admission electrocardiogram (ECG) in patients with acute ST segment elevation myocardial infarction (STEMI) will have prognostic significance in the short term.

METHODS

The study was carried out using retrospectively collected data of 296 consecutive patients diagnosed as acute STEMI .fQRS group had fQRS both in admission and latest ECGs (n = 80, 27%), and non-fQRS group had no fQRS in last ECG (n = 216, 73%). Primary end points were in-hospital cardiovascular mortality, hemodynamic instability, and electrical instability.

RESULTS

MI localization, symptom duration, reperfusion therapy (RPT) rate, RPT modality, rate of successful reperfusion did not differ. Mean ejection fraction was lower and all end points were more frequent in the fQRS group. Irrespective of the RPT modality and success of RPT, mortality rate was higher in patients with persistent fQRS. GRACE score >120 points (OR = 4.765), age >70 years (OR = 4.041), anterior MI localization (OR = 3.148), and presence of fQRS (OR = 2.484) were significant predictors of primary end points. fQRS increased the predictive ability of GRACE score >120 about two folds (OR = 7.305, P < 0.001).

CONCLUSION

Persistent fQRS on ECG is associated with poor prognosis and there is a lack of expected mortality benefit of RPT, particularly that of fibrinolytic therapy, in STEMI patients with fQRS.

Prognostic significance of fragmented QRS complex for predicting the risk of recurrent cardiac events in patients with Q-wave myocardial infarction

There are limited data regarding the prognostic value of QRS complex fragmentation, defined as changes in QRS morphology (<120 ms) with different RSR' patterns: additional R waves, notched S wave, or >1 R' wave. The purpose of our analysis was to assess the prognostic value of presence of Q waves and QRS fragmentation for predicting recurrent cardiac events, defined as cardiac death, nonfatal myocardial infarction (MI), or unstable angina, whichever occurs first, in 350 patients with first Q-wave MI. In follow-up (2 months on average) electrocardiograms (ECGs), 277 patients (79%) had persistent Q waves and 73 (21%) had resolution of Q waves. Independently of Q waves, presence of QRS complex fragmentation was found in 187 patients (53%). Resolved Q waves on 2-month ECGs was associated with worsened prognosis (adjusted hazard ratio [HR] 2.33, p = 0.007), whereas presence of any fragmented QRS did not increase risk of recurrent cardiac events (adjusted HR 0.93, p = 0.79). Among patients for whom Q waves disappeared on 2-month ECGs, patients with QRS fragmentation (n = 37) had over twofold higher risk of recurrent events (adjusted HR 2.68, p = 0.004) compared with those without fragmented QRS and persistent Q waves. In conclusion, presence of fragmented QRS independently of Q waves was not associated with increased risk of recurrent events in the general population of patients after MI. However, among patients with resolved Q waves, fragmented QRS was associated with increased risk of cardiac events. Fragmented QRS complex should not be neglected in patients with transient Q waves after myocardial infarction.

Fragmented QRS on a 12-lead ECG: a predictor of mortality and cardiac events in patients with coronary artery disease

BACKGROUND

Fragmented QRS (fQRS) on a 12-lead electrocardiogram (ECG) is associated with myocardial scar in patients with coronary artery disease (CAD).

OBJECTIVE

We postulated that fQRS is a predictor of cardiac events and mortality in patients who have known CAD or who are being evaluated for CAD.

METHODS

The cardiac events (myocardial infarction, need for revascularization, or cardiac death) and all-cause mortality were retrospectively reviewed in 998 patients (mean age 65.5 +/- 11.9 years, male 967) who underwent nuclear stress test. The fQRS on a 12-lead ECG included various RSR' patterns (> or =1 R' prime or notching of S wave or R wave) without typical bundle branch block in 2 contiguous leads corresponding to a major coronary artery territory.

RESULTS

All-cause mortality (93 [34.1%] vs 188 [25.9%]) and cardiac event rate (135 [49.5%] vs 200 [27.6%]) were higher in the fQRS group compared with the non-fQRS group during a mean follow-up of 57 +/- 23 months. A Kaplan-Meier survival analysis revealed significantly lower event-free survival for cardiac events (P <.001) and all-cause mortality (P = .02). Multivariate Cox regression analysis revealed that significant fQRS was an independent significant predictor for cardiac events but not for all-cause mortality. The Kaplan-Meier survival analysis showed no significant difference between fQRS and Q waves groups for cardiac events (P = .48) and all-cause mortality (P = .08).

CONCLUSION

The fQRS is an independent predictor of cardiac events in patients with CAD. It is associated with significantly lower event-free survival for a cardiac event on long-term follow-up.

Significance of a fragmented QRS complex versus a Q wave in patients with coronary artery disease

BACKGROUND

Q waves on a 12-lead ECG are markers of a prior myocardial infarction (MI). However, they may regress or even disappear over time, and there is no specific ECG sign of a non-Q-wave MI. Fragmented QRS complexes (fQRSs), which include various RSR' patterns, without a typical bundle-branch block are markers of altered ventricular depolarization owing to a prior myocardial scar. We postulated that the presence of an fQRS might improve the ability to detect a prior MI compared with Q waves alone by ECG.

METHODS AND RESULTS

A cohort of 479 consecutive patients (mean+/-SD age, 58.2+/-13.2 years; 283 males) who were referred for nuclear stress tests was studied. The fQRS included various morphologies of the QRS (<120 ms), which included an additional R wave (R') or notching in the nadir of the S wave, or >1 R' (fragmentation) in 2 contiguous leads, corresponding to a major coronary artery territory. The Q wave was present in 71 (14.8%) patients, an fQRS was present in 191 (34.9%) patients, and an fQRS and/or a Q wave was present in 203 (42.3%) patients. Sensitivity, specificity, and the negative predictive value for myocardial scar as detected by single photon emission computed tomography analysis were 36.3%, 99.2%, and 70.8%, respectively, for the Q wave alone; 85.6%, 89%, and 92.7%, respectively, for the fQRS; and 91.4%, 89%, and 94.2%, respectively, for the Q wave and/or fQRS.

CONCLUSIONS

The fQRS on a 12-lead ECG is a marker of a prior MI, defined by regional perfusion abnormalities, which has a substantially higher sensitivity and negative predictive value compared with the Q wave.

Q-wave regression after acute myocardial infarction assessed by Tl-201 myocardial perfusion SPECT

BACKGROUND

The actual relationship between the interval change of myocardial thallium 201 (Tl-201) radioactivity in the infarct area and the pattern of Q-wave regression is still unknown. This study was conducted to evaluate their relationship after acute myocardial infarction (AMI).

METHODS AND RESULTS

A total of 30 patients who had a first Q-wave AMI (11 without Q-wave regression and 19 with Q-wave regression) were retrospectively included. Two sets of 12-lead surface electrocardiograms and Tl-201 myocardial perfusion images were obtained 0 to 2 months and 14 to 84 months after the AMI event, respectively. The acute/subacute redistribution Tl-201 radioactivity was similar between the patients with and those without Q-wave regression. However, the patients with Q-wave regression had higher chronic redistribution Tl-201 radioactivity than those without Q-wave regression. Moreover, the patients with Q-wave regression presented a higher gradient in the redistribution Tl-201 radioactivity between the chronic and acute/subacute images than those without Q-wave regression.

CONCLUSIONS

This study supports the role of functional recovery of stunning and/or hibernating myocardium in the disappearance of Q waves after AMI.