Significance of terminal QRS distortion on the electrocardiogram in acute inferior myocardial infarction / 中国医师进修杂志

Objective To investigate whether terminal QRS distortion on the electrocardiogram in acute inferior myocardial infarction could be as a standard for the infarct-related artery,through comparing to coronary angiography.Methods Fifty-seven patients with acute inferior myocardial infarction were enrolled,among which,the right coronary artery (RCA) occlusion (RCA occlusion group) was present in 29 cases,and left circumflex coronary artery (LCX) occlusion (LCX occlusion group) was in 28 cases.The changes of electrocardiogram was analyzed in 12 hours after the acute episode.Results The incidence of terminal QRS distortion in leads Ⅱ,Ⅲ,aVF in RCA occlusion group was 44.8％(13/29) and 39.3％(11/28)in LCX occlusion group,and there was no significant difference (P ＞ 0.05).The incidence of terminal QRS distortion in leads V4R-V5R in RCA occlusion group was 17.2％(5/29) and 7.1％(2/28) in LCX occlusion group,and there was no significant difference (P ＞ 0.05).The incidence of terminal QRS distortion in leads V7-V9 in RCA occlusion group was 6.9％(2/29),which was lower than that in LCX occlusion group[53.6％(15/28)],and there was significant difference (P ＜ 0.05).For identifying LCX as the infarct-related artery of acute inferior myocardial infarction,the sensitivity,specificity,positive and negative value in terminal QRS distortion in leads V7-V9 were 53.6％ (15/28),93.1％ (27/29),88.2％ (15/17),67.5％ (27/40).The area under curve of terminal QRS distortion in leads V7-V9 in identifying LCX as the infarct-related artery of acute inferior myocardial infarction was 0.733 (95％ CI 0.599-0.868).Conclusion Terminal QRS distortion in leads V7-V9 may be of diagnostic value in identifying the infarct-related artery in acute inferior myocardial infarction.

QRS distortion increased risk re-occurrence acute coronary events.

Nearly 50% of patients suffering inferior myocardial infarction will have complications or distinguishing features associated with an increased mortality. This study aimed to identify dominant risk factors related to re-occurrence of acute coronary events in patients with inferior myocardial infarction. This historical cohort included patients with inferior myocardial infarction who received fibrinolytic therapy at emergency department of National Cardiovascular Center Harapan Kita, Jakarta during 2001 to 2004 and was followed-up for two years. Patients with previous myocardial infarction, left bundle branch block, ventricular rhythm, and ventricular pacing were excluded. QRS distortion is ratio between J-point and R wave more than 50% at 2 or more inferior leads. Re-occurrence of acute coronary events is incident of myocardial infarction and unstable angina pectoris. Of 181 subjects with inferior AMI, there were 21 (11.6%) incidents of acute coronary event. Those who had positive than negative QRS distortion had almost three-fold increased risk for re-occurrence of acute coronary events [adjusted relative risk (RRa) 2.88; 95% confidence interval (CI) = 1.05 – 7.90]. In term of TIMI risk score, those with higher than lower risk score had 6.7 times higher risk to be re-occurrence of acute coronary events (RRa = 6.66; 95% CI = 1.94 – 22.92). However, those who had than did not have successful fibrinolysis had 57% lower risk to be re-occurrence of acute coronary event (RRa = 0.43; 95% CI = 0.18 – 1.05; P = 0.065). Re-occurrence acute coronary events were related to QRS distortion, TIMI risk score, and successful fibrinolysis.

Terminal QRS Complex Distortion on the Admission Electrocardiogram in Anterior Acute Myocardial Infarction and Association with Residual Flow and Infarct Size after Primary Angioplasty

BACKGROUND: Terminal QRS complex distortion on admission is a simple and reliable predictor of infarct size in patients with acute myocardial infarction (AMI). It is uncertain, however, whether this reflects reduced myocardial perfusion of the infarct area and a larger area of the myocardium at risk. This study was conducted to investigate whether terminal QRS distortion complex on admission is a reliable predictor of reduced residual flow and a larger area of the myocardium at risk compared to patients who are admitted without a terminal QRS distortion. METHODS: We evaluated the relationship between terminal QRS complex distortion and residual flow to the infarct zone and risk area in 46 anterior AMI patients undergoing primary angioplasty. 99mTc-sestamibi imaging was performed at baseline and 5-9 days after angioplasty. The study population was divided into those with (Group I, n=16) and without (Group II, n=30) terminal QRS complex distortion. RESULTS: Baseline characteristics were similar between the two groups. The area of the myocardium at risk was higher in Group I (59.9 +/- 15.3%) than in Group II (48.6 +/- 13.7%, p< 0.05; mean+SD) while the nadir measurement of the residual flow was lower in Group I (0.10 +/- 0.07) than in Group II (0.16 +/- 0.09, p< 0.05). Although the final infarct size was significantly higher in Group I (40.8 +/- 17.2%) than in Group II (27.1 +/- 18.1%, p< 0.05), the myocardial salvage index did not differ significantly between the two groups. CONCLUSION: Terminal QRS complex distortion seems to be associated with less residual flow to the infarct zone, a larger risk area and greater infarct size in patients with anterior AMI.