完全性房室阻滞在急性下壁心肌梗死合并及不合并右室梗死病人的预后意义

目的　确定完全性房室阻滞（ＣＡＶＢ）对急性下壁心肌梗死（ＡＩＭＩ）伴有或不伴有右室梗死（ＲＶＩ）病人预后的影响。方法　分析２６５ 例ＡＩＭＩ病人临床资料,２２２ 例无合并ＲＶＩ的病人（Ⅰ组）,４３例合并ＲＶＩ病人（Ⅱ组）,根据住院期间有无合并ＣＡＶＢ再将其分为两个亚组（无合并ＣＡＶＢ组（Ⅰａ、Ⅱａ组）及合并ＣＡＶＢ组（Ⅰｂ、Ⅱｂ 组））。选择临床及实验室资料进行比较。结果　（１）ＡＩＭＩ合并ＣＡＶＢ明显增加心脏并发症的发生率,Ｐ＜ ０．０１;ＡＭＩ合并ＲＶＩ虽有增高趋势,但无显著性差异;（２）溶栓治疗显著降低ＡＩＭＩ住院期间死亡率,特别是ＡＩＭＩ同时合并ＲＶＩ和ＣＡＶＢ的病人,Ｐ＜ ０．０５;（３）与ＣＡＶＢ、ＲＶＩ并存的ＡＩＭＩ以心脏合并症及ＣＫ峰值居高,住院死亡率显著为特点。结论　ＡＩＭＩ合并ＣＡＶＢ及ＲＶＩ表现出极高的心脏合并症发生率及住院死亡率可能是梗面积较大的结果,但是ＲＶＩ及ＣＡＶＢ的协同作用可能是影响ＡＩＭＩ预后的另外因素。     

Prognostic significance of right ventricular dysfunction in patients with acute inferior myocardial infarction and right ventricular involvement

Little is known about the influence of right ventricular (RV) dysfunction on prognosis of patients with acute inferior myocardial infarction (IMI) and RV involvement. Therefore, 99 consecutive patients (mean age 56.6 ± 3.4 years) with RV involvement during acute IMI were followed for a 12-month period to clarify the influence of acute RV dysfunction on short- and long-term survivals. Forty-one patients with IMI evolved with severe arterial hypotension due to RV dysfunction, while 58 patients had no hemodynamic impairment due to RV involvement. Basal hemodynamic data (mean ± SD) for patients with RV dysfunction were blood pressure (BP) 92/59 ± 22/20 mmHg, systemic vascular resistance (SVR) 2314 ± 252 dynes·s·cm^?5, and cardiac index (CI) 1.3 ± 0.31/min/m². Patients without RV dysfunction demonstrated BP 113/74 ± 20/16 mmHg (p≤0.05), SVR 1324 ± 354 dynes·s·cm^?5 (p≤0.01), and CI 2.6 ± 0.5 1/min/m² (p≤0.05). Angiographic differences noted were that hemodynamically compromised patients showed lower RV ejection fractions (0.27 ± 0.08) than patients without hemodynamic disturbance [0.41 ± 0.11 (p≤0.05)]; however, left ventricular ejection fractions were 0.48 ± 0.10 and 0.52 ± 0.12, respectively. Short- and long-term mortality rates were assessed during the follow-up period. Patients with hemodynamic impairment due to RV infarction had a higher mortality rate for the first month and for 11 subsequent months post MI than patients without hemodynamic impairment, that is, 24.4 vs. 6.9 and 14.6 (p≤0.05) vs. 3.4% (p≤0.05), respectively. These data suggest that decreased RV ejection fraction possibly is linked with significantly reduced short- and long-term survival in patients with RV involvement during acute IMI.     

急性下壁心肌梗塞中右室心肌梗塞与房室传导阻滞的关系

目的 探讨急性下壁心肌梗塞(MI)并发右室MI与发生房室传导阻滞的关系.方法 共有120例确诊急性下壁MI的住院患者,根据是否发生房室传导阻滞分为房室传导阻滞组(AVB)和非房室传导阻滞(NAVB)组;是否合并右室MI,则分为右室MI(RVI)组和非右室MI(NRVI)组.结果 急性下壁MI并发AVB组住院死亡率明显高于NAVB组(P<0.05);合并RVI患者,其AVB的发生率明显高于NRVI病人(P<0.01).合并RVI及高血压组患者,其AVB的发生率最高,明显高于RVI组(P<0.05).结论 右室心肌MI是急性下壁心肌MI发生AVB的重要原因之一.     

Left and right ventricular function in inferior acute myocardial infarction and significance of advanced atrioventricular block

Of 139 consecutive patients with a first inferior acute myocardial infarction, 26 (19%) had advanced atrioventricular (AV) block and 113 (81%) did not. All were evaluated by 2-dimensional echocardiography (2-D echo) and radionuclide angiography. Patients with advanced AV block had lower radionuclide left ventricular (LV) ejection fraction (51 +/- 10 vs 58 +/- 11%, p less than 0.01), higher LV wall motion score on 2-D echo (5.6 +/- 2.6 vs 3.1 +/- 2.7, p less than 0.001), lower radionuclide right ventricular (RV) ejection fraction (32 +/- 15 vs 39 +/- 16%, p less than 0.001) and higher RV wall motion score on 2-D echo (3.4 +/- 1.7 vs 1.5 +/- 2, p less than 0.002) than did patients without AV block. The incidence rate of RV dysfunction was higher in patients with advanced AV block (78 vs 40%, p less than 0.02), and the mortality rate was also higher (although not significantly) in patients with advanced AV block (15 vs 6%). In conclusion, patients with inferior acute myocardial infarction and advanced AV block have larger infarct sizes (as seen on radionuclide angiography and 2-D echo) and lower RV and LV function than patients without AV block. This finding may explain the higher mortality rate observed in this group.     

急性下壁心肌梗死合并及不合并右室梗死溶栓疗效分析

目的：确定急性下壁心肌梗死（AIMI）合并或不合并右室梗死（RVI）患溶栓治疗的价值。方法：265例AIMI患中43事并RVI,分为I组（AIMI组）及Ⅱ组（AIMI＋RVI组）,分别就是否接受溶栓治疗,住院期间死亡率及并发症发生率进行对比观察。结果：（1）Ⅱ组合并高血压,糖尿病多于I组,其中糖尿病差异具极显意义（P＜0．01）,（2）263例AIMI中接受溶栓治疗的140例,未接受溶栓治疗的125例的住院死亡率分别是11．4％,21．6％,（P＜0．05）,（3）,I,Ⅱ组用溶栓治疗时病死率分别为11．2％,12．5％,无显差异,未用溶栓治疗时病死率17．9％,42．1％（P＜0．01）。结论：AIMI组溶栓治疗住院期间死亡率较非溶栓治疗组的明显降低;AIMI＋RVI溶栓较单纯AIMI溶栓治疗益处更为显。     

Prognostic importance of complete atrioventricular block complicating acute myocardial infarction

Third-degree atrioventricular block after acute myocardial infarction is considered to have prognostic importance. However, its importance in conjunction with thrombolytic therapy and its relation to left ventricular function remains uncertain. This report also outlines an important distinction between atrioventricular block in the setting of anterior and inferior wall acute myocardial infarction, with profound clinical and prognostic implications.     

Prognostic significance of second and third degree atrioventricular block in acute inferior wall myocardial infarction

High degree atrioventricular block complicates inferior wall acute myocardial infarction in 10 to 15% of cases. Its significance is still controversial. In this study, we have analysed 152 observations of acute inferior wall myocardial infarction during hospitalisation period. The mean age of our patients is 60 years, 48.7% of them have received fibrinolytic treatment. Second or third degree atrioventricular block was detected in 33 cases (21.7%). Mortality is higher in inferior wall myocardial infarctions with atrioventricular block than in those without atrioventricular block (12% versus 2.5%, p < 0.05). Hemodynamic complications like cardiogenic shock due to the extension of the infarction to the right ventricle and left ventricle insufficiency are more frequent (18% versus 3.4%, p < 0.01 and 12% versus 3.5%, p < 0.01 respectively). It appears that the infracted mass of myocardium is larger in case of atrioventricular block, this is assessed by comparing the average value of the peak of creatine Kinase in the two groups with and without atrioventricular block (1534 IU versus 1096 IU, p < 0.02) and by considering the rate of low ejection fraction (EF < 40%) in each group (44.6% versus 16%, p < 0.01). In our study, we note that thrombolysis does not affect the incidence of atrioventricular block (19% and 24% in thrombolyed and not thrombolyzed patients respectively) but it seems that thrombolysis improves the outcome of these patients. The occurrence of atrioventricular block in acute inferior wall myocardial infarction is related to the presence of an important right coronary artery that is occluded, the recanalisation of this vessel leads often to rapid regression of the block that is no longer pejorative.     

Long-term outcome in patients with inferior myocardial infarction and complete atrioventricular block

Some studies have reported increased short-term mortality and higher incidence of multivessel coronary artery disease in patients with inferior myocardial infarction and complete heart block, but information is lacking on clinical outcome after hospital discharge. Therefore, data were obtained and analyzed in 749 patients who were admitted with inferior myocardial infarction to four different centers and followed up for 1 year. Six hundred fifty-four patients (Group 1) did not have complete heart block and 95 (Group 2) had complete heart block during their hospital stay (incidence rate 12.8%). Compared with Group 1, Group 2 patients were older (66 versus 61 years, p less than 0.01), more often had signs of left ventricular failure (p less than 0.001) and had higher peak creatine kinase values (1,840 versus 1,322 IU/liter, p less than 0.001). The in-hospital mortality rate was higher in Group 2 than in Group 1 (24.2 versus 6.3%, p less than 0.001). However, at discharge there was no difference between Group 1 and Group 2 in clinical characteristics, left ventricular ejection fraction (0.52 +/- 0.12 versus 0.52 +/- 0.11) or incidence of complex ventricular arrhythmias on ambulatory electrocardiographic monitoring. Furthermore, during the year after hospital discharge, patients in Groups 1 and 2 did not have significantly different mortality rates (6.4 versus 10.1%, p = NS). The incidence rate of reinfarction (4%) was the same in Groups 1 and 2. The incidence of coronary artery bypass surgery was slightly but not significantly higher in Group 1 compared with Group 2 (11 versus 4%).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of thrombolytic therapy in acute inferior myocardial infarction with or without right ventricular involvement

Objectives. This study assessed the prognostic impact of right ventricular involvement (RVI) in streptokinase-treated patients with inferior acute myocardial infarction (AMI) stratified for small or large AMI.Background. Only scant data exist from small studies about the impact of reperfusion therapy on survival in patients with RVI during inferior AMI.Methods. Right ventricular involvement was assessed by ST-segment elevation ≥0.1 mV in lead V₄R and infarct size by the extent of ST-segment deviation on the baseline electrocardiogram: small AMI = sum ST-segment elevation ≤0.8 mV and no precordial ST-segment depression (small ST); large AMI = presence of precordial ST-segment depression or sum ST-segment elevation >0.8 mV (large ST) in 522 inferior AMI patients of the Hirudin for Improvement of Thrombolysis (HIT-4) Trial. In 187 patients, 90-min coronary angiography was performed.Results. Right ventricular involvement was present in 169 patients (32%). Higher 30-day cardiac mortality rates with RVI (5.9% vs. 2.5%) were related to larger infarct size rather than to RVI. For large ST, a proximal right coronary artery lesion was observed in 52% with and in 23% without RVI. Patency rates at 90 min were similar (54% vs. 52%). In the 28% of patients who had small ST, cardiac mortality was less than 1% irrespective of the presence of RVI. Coronary artery lesions were mostly located distally. Patency rates were 27% with and 80% without RVI.Conclusions. ST-segment elevation of ≥0.1 mV in V₄R in inferior AMI patients is associated with larger infarct size and higher 30-day mortality rates. Right ventricular involvement is not an independent predictor of survival. In patients with small ST, cardiac mortality is low, even if ST V₄R is ≥0.1 mV.     

Long-term prognostic significance of atrioventricular block in inferior acute myocardial infarction

Among 477 consecutive patients admitted for inferior acute myocardial infarction (AMI), 2nd or 3rd degree atrioventricular (AV) block developed in 88 (20%). Compared with the 359 without AV block, these 88 patients presented a higher incidence of Killip class greater than 1 (52% vs 28%, P less than 0.001), pericarditis (30% vs 17%, P less than 0.01), atrial fibrillation (26% vs 11%, P less than 0.01), complete bundle branch block (12% vs 4%, P less than 0.01) and in-hospital mortality (24% vs 4%, P less than 0.001). The 3-year post-hospital mortality was not significantly different in the two groups (12% vs 15%). Among the 88 patients with AV block, those who died at hospital were older (66 +/- 11 vs 59 +/- 11 years, P less than 0.05), had a higher incidence of Killip class greater than 1 (86% vs 42%, P less than 0.001) and bundle branch block (29% vs 7%, P less than 0.05). Thus, patients with inferior AMI who developed AV block had a poor hospital outcome but long-term prognosis was similar in hospital survivors who had AV block and in those without this complication.     

Mechanism and significance of widened QRS complexes during complete atrioventricular block in acute inferior myocardial infarction

Twelve of 35 consecutive patients admitted with complete, atrioventricular (A-V) block complicating acute inferior myocardial infarction manifested widened QRS complexes. The escape beats had the pattern of left bundle branch block in four patients, right bundle branch block in five patients and both left and right bundle branch block in three patients.

His bundle recordings in five patients with escape beats that had a left bundle branch block configuration revealed a His bundle potential preceding the widened QRS complex at His-V intervals of 45 to 60 msec. Bradycardia-dependent left bundle branch block was demonstrated in two patients by His bundle pacing. In three patients the conducted beats had a left bundle branch block configuration after critical lengthening of the R-R interval during second degree A-V block before or after the episode of complete A-V block. In six patients whose escape beats had a right bundle branch block configuration, His bundle recordings did not reveal a His bundle potential preceding these beats.

Our observations suggest that widened QRS complexes with a left bundle branch block configuration could be due to an A-V junctional escape rhythm with phase 4 left bundle branch block. Alternatively in association with a right bundle branch block configuration it is possible that the widened QRS complexes represent a ventricular or fascicular escape rhythm.

Two of 12 patients with widened QRS complexes died. There were no significant differences in immediate mortality, 6 month mortality or mean peak serum glutamic oxaloacetic transaminase (SGOT) values between patients with narrow and widened QRS complexes. This finding suggests that widened QRS complexes during complete A-V block in acute inferior myocardial infarction have no prognostic significance.     

单纯急性下壁心肌梗死及其合并右心室心肌梗死对右心长轴功能的影响

目的应用心肌组织多普勒技术结合M型超声心动图,评价单纯急性下壁心肌梗死及其合并右心室心肌梗死对右心室长轴功能的影响。方法选择首次急性下壁心肌梗死患者28例,分为单纯急性下壁心肌梗死18例(Ⅰ组),急性下壁心肌梗死伴右心室心肌梗死10例(Ⅱ组),另选健康体检者20例(Ⅲ组)。在标准心尖四腔心切面二维图像指引下,应用M型超声记录右心房室环右心室游离壁及中心纤维支架处运动曲线,测量收缩期、舒张早期、舒张晚期最大运动幅度(SD,DED,DAD)及收缩期、舒张早期、舒张晚期平均运动速度(SMV,DEMV,DAMV),计算DED/DAD比值。心肌组织多普勒记录该处运动速度曲线,测量上述各期最大运动速度(Sm、Em、Am)及Em/Am比值。结果与Ⅲ组比较,Ⅰ组和Ⅱ组右心房室环右心室游离壁处SD、DED、DED/DAD、SMV、DEMV、Sm及Em均明显下降。DAD、DAMV、Am虽有下降,但差异无统计学意义。结论急性下壁心肌梗死无论是否合并右心室心肌梗死均可影响右心室长轴功能,导致右心室整体功能降低。     

Prognostic significance of right ventricular ejection fraction following inferior myocardial infarction

The prognostic significance of right ventricular ejection fraction, measured by radionuclide ventriculography, was assessed in 168 consecutive patients with inferior myocardial infarction. Right ventricular ejection fraction was 0.40 or less in 35 patients. Over a follow-up period of 40 months, there were 15 deaths in the total group of 168 patients, eight (23%) in the 35 with right ventricular ejection fraction of 0.40 or less, and seven (5%) in the remainder of the group. The one year survival of patients with right ventricular impairment (84 +/- 6%) was significantly worse (P less than 0.01) than those with a right ventricular ejection fraction over 0.40 (95 +/- 2%). A multivariate Cox model analysis showed age (P less than 0.001), left ventricular ejection fraction (P less than 0.01), and right ventricular ejection fraction (P less than 0.03) to be independent predictors of survival. Impaired right ventricular function is an adverse prognostic factor in patients with inferior infarction, particularly in those with impaired left ventricular function.     

急性下壁梗死伴或不伴右心室心肌梗死患者临床特征的比较

目的：比较急性下壁心肌梗死（IWMI）伴或不伴右心室心肌梗死（RVMI）患者的临床特征差异。方法纳入2006年10月~2012年12月总参保健处发病12 h内入院的急性下壁心肌梗死（IWMI）患者256例,根据冠状动脉造影（CAG）结果将患者分为IWMI不合并RVMI组（n=167）和IWMI合并RVMI组（n=89）,比较两组患者冠心病发病主要危险因素（包括吸烟、高血压、糖尿病、高脂血症、冠心病家族史）、临床表现、并发症和治疗用药的差异。结果两组患者冠心病主要危险因素无差异（P＞0.05）。IWMI合并RVMI患者出现低血压（80.0% vs.19.8%,P＜0.05）、颈静脉怒张（50.6%vs.1.8%）和Kussmaul征（51.7%vs.1.2%）的比例明显增加（P均＜0.01）,需要更多地应用正性肌力药物（60.7%vs.16.2%）来维持血压,且病死率较高（77.9%vs.0.6%,P＜0.05）。结论在IWMI基础上伴RVMI多合并右心功能障碍,可导致预后不良。     

Severe intracranial bleeding mimicking acute inferior myocardial infarction with right ventricular involvement

Electrocardiographic (ECG) changes and wall motion abnormalities of the left ventricle have been observed in patients with severe intracranial hemorrhage. However, ECG evidence of an acute myocardial infarction in this setting is extremely rare but may have important therapeutic consequences. We report the case of a 45-year-old female who became unconscious with respiratory insufficiency after an endoscopic retrograde cholangiopancreaticoscopy with ECG changes consistent of an inferior myocardial infarction with right ventricular involvement. Immediate coronary angiography revealed normal coronaries; however, left ventricular angiography showed extensive wall motion abnormalities predominantly in the anteroseptal region. Immediate cranial computer tomography demonstrated massive intracranial bleeding. Intracranial hemorrhage can be associated in the initial phase with ECG evidence of an acute myocardial infarction. This has to be taken into consideration in the setting of unexplained loss of consciousness or nonresponsiveness of a patient. A rapid diagnostic evaluation has to be initiated to rule out a myocardial infarction and to diagnose intracranial hemorrhage before the use of thrombolytic or anticoagulant therapy.     

Prognostic significance of persistent right ventricular dysfunction as assessed by radionuclide angiocardiography in patients with inferior wall acute myocardial infarction

We evaluated cardiac hemodynamics and long-term prognosis in patients with right ventricular (RV) acute myocardial infarction (AMI) using Fourier phase and amplitude analysis of radionuclide angiocardiographic scanning. In 143 patients with RV AMI, delayed phase and low amplitude in radionuclide RV images persisted in 54 patients (persistent RV dysfunction group) 3 months after AMI, but disappeared in the remaining 89 patients (improved RV function group). No significant differences were present in RV dimensions, left ventricular (LV) wall motion, LV ejection fraction, or RV ejection fraction between these groups during the acute phase. At 3 months, RV dimension and LV and RV wall motion indexes were significantly higher (p = 0.0292, p = 0.0124, p<0.0001, respectively), and LV and RV ejection fractions were lower (p = 0. 0174 and p = 0.0008, respectively) in the persistent RV dysfunction group. Percutaneous transluminal coronary angioplasty in the acute phase was performed in a smaller group of patients (15% vs. 34%, p = 0.0223), and the degree of residual stenosis in the proximal right coronary artery was significantly greater in the persistent RV dysfunction group than in the improved RV function group (82+/-22% vs. 53+/-30%, p<0.0001). The 8-year survival rate was significantly lower in the persistent RV dysfunction group (p<0.0001). Persistent abnormality of phase and amplitude in radionuclide RV images was a significant independent predictor of long-term survival (odds ratio 10.42; 95% confidence interval 3.65 to 29.71; p<0.0001). Radionuclide angiocardiographic Fourier phase and amplitude scanning can detect persistent RV dysfunction in patients with RV AMI and can predict patient outcome.     

Paroxysmal atrioventricular block and right coronary artery stenosis without acute myocardial infarction

Tako-Tsubo Cardiomyopathy (TTC) is described as transient left ventricular (LV) dysfunction without coronary artery stenoses. Typically the onset of TTC-syndrome is following emotional or physical stress. As an acute cardiac syndrome it is mimicking ST-elevation myocardial infarction. In this case we report from a 73-year old woman presenting with cardiac arrest after a long-distance bus-tour, and ongoing resuscitation to our ICU. Advanced life support with temporary ventricular pacing was continued until onset of stable spontaneous circulation. Left ventricular angiography revealed normal coronary arteries and the typical apical ballooning phenomenon. Echocardiographic findings resolved completely within 10 days. The patient survived, achieved good cerebral recovery (CPC 1) and was alert and fully oriented on discharge after 18 days.     

Value of electrocardiogram in diagnosing right ventricular involvement in patients with an acute inferior wall myocardial infarction

To study the value of the electrocardiogram in diagnosing right ventricular involvement in acute inferior wall myocardial infarction, the electrocardiographic findings were analysed in 67 patients who had had scintigraphy to pin-point the infarct. All 67 patients were consecutively admitted because of an acute inferior wall infarction. A 12 lead electrocardiogram with four additional right precordial leads (V3R, V4R, V5R, and V6R) was routinely recorded on admission and every eight hours thereafter for three consecutive days. Thirty-six to 72 hours after the onset of chest pain a 99mtechnetium pyrophosphate scintigraphy and a dynamic flow study were performed to detect right ventricular involvement, which was found in 29 of the 67 patients (43%). ST segment elevation greater than or equal to 1 mm in leads V3R, V4R, V5R, and V6R is a reliable sign of right ventricular involvement. ST segment elevation greater than or equal to 1 mm in lead V4R was found to have the greatest sensitivity (93%) and predictive accuracy (93%). The diagnostic value of a QS pattern in lead V3R and V4R or ST elevation greater than or equal to 1 mm in lead V1 was much lower. ST segment elevation in the right precordial leads was short lived, having disappeared within 10 hours after the onset of chest pain in half of our patients with right ventricular involvement. When electrocardiograms are recorded in patients with an acute inferior wall infarction within 10 hours after the onset of chest pain, additional right ventricular infarction can easily be diagnosed by recording lead V4R.     

Automatic backscatter analysis of regional right ventricular systolic function using colour kinesis in patients with inferior wall acute myocardial infarction with or without right ventricular involvement

BACKGROUND: In patients with inferior acute myocardial infarction (AMI), right ventricular (RV) function is an important determinant of global cardiac performance, prognosis, and exercise capacity. Several echocardiographic methods for quantifying RV function have been developed over the years but the usefulness of colour kinesis (CK) and acoustic quantification (AQ) have not yet been investigated. AIM: To test whether AQ and CK may provide quantitative assessment of global and regional RV function in patients with inferior AMI. METHODS: Thirty two consecutive patients with recent inferior AMI with or without RV involvement (n=17 and n=15, respectively), and 15 age- and gender-matched controls were studied. The graphs of RV fractional area change were displayed along with ECG and the concurrent cross sectional image. CK digitised end-systolic images of RV and were evaluated by reviewing the stored loops obtained from normal subjects and patients. To evaluate the entire RV systolic endocardial excursion, further quantitative CK analysis was performed by measuring the systolic segmental endocardial motion (SEM). RESULTS: In comparison with the control group, patients with inferior AMI with or without RV involvement had reduced RV fractional area change (30+/-7%, 36+/-6%,45+/-6%, p<0.05, p<0.01 respectively), reduced mean free wall SEM (3.9+/-1.1 mm, 5.2+/-1.3 mm, 6.3+/-1.4 mm, p<0.05, p<0.01 respectively) and mean septal wall SEM (4.9+/-1.2 mm, 6.4+/-1.5 mm, 7.2+/-1.4 mm, p<0.05, p<0.05, respectively). CONCLUSIONS: Our results confirmed that RV systolic functions are significantly more altered in patients with inferior AMI than in controls, and that RV abnormalities are more pronounced in patients with rather than without RV involvement. AQ and CK are able to detect wall motion disturbances in patients with inferior AMI with RV involvement.