Inferior Wall ST-elevation Myocardial Infarction Research Articles

Alteration in the global and regional myocardial strain patterns in patients with inferior ST-elevation myocardial infarction prior to and after percutaneous coronary intervention

This study was designed to investigate the alteration on regional and global strains of left and right ventricle (LV, RV) in patients with inferior wall ST-elevation myocardial infarction (MI). Patients were examined prior to and 7 days after percutaneous coronary intervention (PCI) using speckle-tracking techniques. Fifty-nine patients (36 males and 23 females) and 60 healthy controls (40 males and 20 females) were enrolled in this study. LV strains were measured from three deformations including radial, longitudinal, and circumferential. RV strains were measured only from the longitudinal. Three types of LV global strains were significantly lower in patients than in controls, and LV global longitudinal and circumferential strains were moderately improved by PCI. The LV regional strains reduced significantly in most of the segments (87%) after inferior wall MI and over half of them (60%) were improved by PCI. The RV global longitudinal strains were significantly lower in patients than in controls, and they were moderately improved by PCI. In conclusion, the regional and global strains of LV and RV were reduced in patients with inferior wall MI, and PCI most markedly improved the global strains and regional strains of the infarct and adjacent myocardium in the apical and middle levels.

An unusual case of silent acute ST-elevation myocardial infarction following amphetamine use

We report a case of silent acute ST-elevation myocardial infarction associated with amphetamine use in a 62 years old diabetic man. The patient was devoid of chest pain and had a normal cardiac enzyme analysis at the initial presentation. A routine electrocardiogram demonstrated acute inferior wall ST-elevation myocardial infarction. Coronary angiography confirmed a total occlusion of the posterior lateral branch of right coronary artery. The patient underwent successful percutaneous transluminal coronary angioplasty with stent placement. Amphetamine abuse may play a role in acute myocardial infarction. Adverse cardiovascular manifestations of amphetamine can occur with sudden overt chest pain or present insidiously. In view of the potential association of amphetamine and myocardial infarction, physicians should not rely only upon clinical symptoms. This report highlights the diabetic patients with amphetamine abuse should undergo a routine electrocardiogram in such circumstances.

Comparison of Prognostic Outcome Between Left Circumflex Artery–Related and Right Coronary Artery–Related Acute Inferior Wall Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention

This study evaluated the 30-day clinical outcome of patients with acute inferior wall ST-elevation myocardial infarction (AIW-STEMI) from occlusion of the left circumflex artery (LCX) vs the right coronary artery (RCA) undergoing primary percutaneous coronary intervention (PCI). The clinical outcomes of AIW-STEMI caused by RCA and LCX occlusion may be different for patients undergoing primary PCI. Between May 2002 and September 2009, 646 consecutive patients with AIW-STEMI undergoing primary PCI were enrolled. Of these patients, 520 (80.5%) with AIW-STEMI caused by RCA occlusion were categorized into group 1, whereas the remaining 126 (19.5%) whose AIW-STEMI was caused by LCX occlusion served as group 2. The results demonstrated that the frequency of advanced congestive heart failure, respiratory failure requiring mechanical ventilatory support, and 30-day mortality were remarkably higher in group 2 than in group 1 (all P < 0.01). Conversely, the incidence of right ventricular infarction and complete heart block were notably higher in group 1 than in group 2 (all P < 0.001). Additionally, the peak level of creatine kinase-isoenzyme MB was significantly higher, whereas the left ventricular ejection fraction was notably lower in group 2 than in group 1. Multivariate analysis demonstrated that advanced CHF, high serum creatinine level, low systolic blood pressure, low left ventricular ejection fraction, and LCX as the infarct-related artery were significantly and independently predictive of 30-day mortality (all P < 0.05). The 30-day prognostic outcome was less favorable in LCX-related AIW-STEMI compared with RCA-related AIW-STEMI undergoing primary PCI.

Assessment of Right Ventricular Diastolic Function by Tissue Doppler Imaging in Patients with Acute Right Ventricular Myocardial Infarction

It is known that right ventricular systolic parameters as assessed by color tissue Doppler imaging (TDI) are abnormal in patients with inferior wall ST elevation myocardial infarction (IWMI) with right ventricular myocardial infarction (RVMI). This study was undertaken to determine right ventricular diastolic function as assessed by TDI in patients with acute RVMI. Thirty-five patients with first IWMI were studied and compared with 20 age-matched healthy controls, and categorized into those with (14 patients) and without (21 patients) RVMI based on standard ECG criteria. Peak systolic, peak early and late diastolic velocities (Sm, Em, and Am), Em/Am ratio along with time to Sm (ECG Q-Sm) and time to Em (ECG Q-Em) were acquired from the apical 4-chamber view at the lateral side of tricuspid annulus using TDI. Sm, Em, and Em/Am ratio was reduced significantly in patients with RVMI as compared with those without RVMI and healthy individuals (Sm [11.1 + or - 2.9] vs. [14 + or - 1.9] and [14.5 + or - 2.1] cm/sec, P < 0.01; Em [9.2 + or - 3.5] vs. [12.9 + or - 3] and [14.0 + or - 2.0] cm/sec, P < 0.01; Em/Am ratio 0.53 + or - 0.2 vs. 0.78 + or - 0.19 and 0.8 + or - 0.3 [P < 0.0001]). Among the intervals, there was significant prolongation of Q-Em (558 + or - 14.8 vs. 507 + or - 16.2 and 480 + or - 20 ms [P < 0.0001]) but Q-Sm and Am were not statistically different between the groups. Right ventricular TDI diastolic parameters are abnormal in patients with RVMI. The method of recording the velocities and time intervals are simple and can be used to assess right ventricular diastolic function in patients with RVMI. (Echocardiography 2010;27:539-543).

Electrocardiographic algorithms for predicting the complexity of coronary artery lesions in ST-segment elevation myocardial infarction in ED

Objective In reperfusion strategy for ST-elevation myocardial infarction (STEMI), emergency surgical bypass grafting might be considered for patients with significant multivessel coronary diseases complicated by cardiogenic shock. The culprit lesions in STEMI can be predicted from electrocardiographic (ECG) findings. However, whether the complexity of coronary artery lesions in STEMI can be predicted from characteristic ECG findings remained unclear. Materials and Methods The initial 12-lead ECG parameters in each lead recording from patients with STEMI receiving primary percutaneous coronary intervention within 12 hours were retrospectively analyzed. A sequential ECG algorithm was developed to predict the complexity of coronary artery lesions. Results In patients with inferior wall STEMI, the presence of the following 2-step criteria indicated 3-vessel disease (3VD), with a sensitivity of 92.1% and a specificity of 81.8%: (1) ST depression or flat T wave in leads V 5 or V 6; and (2) ST elevation of more than 2 mm in at least 1 of II, III, aVF, or Q (loss of septal r) without ST elevation in aVR. In patients with anterior wall STEMI, the following criteria indicated 3VD: (1) ST elevation of more than 4 mm in at least 1 of the precordial leads and combined with QRS interval of more than 120 ms; then (2) a flat T wave over aVR, or aVL combined with flat T wave ST depression over lead I or Q wave over all leads II, III, and aVF. This algorithm detects patients with 3VD with a sensitivity of 76.5% and a specificity of 100%. However, when the whole algorithm is completed, the sensitivity can reach up to 88.4% and the specificity can still be 100%. Conclusion By using this ECG algorithm, 3VD might be distinguished early from single-vessel disease in patients with STEMI for appropriate reperfusion strategy.

Pseudoaneurysm and Intracardiac Fistula Caused by an Infected Paclitaxel-Eluting Coronary Stent

A 54-year-old man with end-stage renal disease presented with chest pain. Five months before presentation the patient had a right-foot cellulitis that was treated with amoxicillin clavulanate. Two weeks later, the patient suffered an inferior wall ST-elevation myocardial infarction that required immediate percutaneous coronary intervention with paclitaxel-eluting stents (Taxus, Boston Scientific, Natick, Mass) in the proximal and mid-right coronary artery (RCA). Over the next 4 months, the patient had recurrent fevers and grew Staphylococcus aureus on repeat blood cultures. The source of infection was attributed to recurrent infected dialysis catheters. The patient had 3 catheter replacements and was treated with intravenous vancomycin and oral rifampin. On examination, the patient had a continuous murmur along the right sternal border and an elevated troponin I level of 2.45 …

The electrocardiogram in right ventricular myocardial infarction

Right ventricular (RV) myocardial infarction most often occurs in the setting of inferior wall myocardial infarction. Right ventricular infarction complicates approximately 25% (range, 20%-60%) of inferior acute myocardial infarction; it is uncommon to quite rare in anterior and lateral wall acute myocardial infarction. With infarction of the RV, the RV will fail. As such, left ventricular filling pressures are entirely dependent upon the patient's preload; with significant reductions in the preload, hypotension likely results (this hypotension may be worsened by nitroglycerin and morphine). The clinical presentation, in the setting of an ST-elevation myocardial infarction (STEMI) of the inferior wall, involves hypotension, jugular venous distension, and the following electrocardiographic findings: ST-segment elevation of greatest magnitude in lead III (compared with leads II and aVF), ST-segment elevation in lead V 1, and/or ST-segment elevation in right chest leads (RV 1 through RV 6). Therapy, in addition to appropriate management for STEMI, relies largely on enhancing the preload with intravenous fluid and judicious use of vasodilator medications. Patients with inferior wall STEMI with RV infarction have a markedly worse prognosis (both acute cardiovascular complications and death) compared with patients with isolated inferior wall STEMI.