Prognostic significance of complete atrioventricular block in patients with acute inferior myocardial infarction with and without right ventricular involvement

Data were obtained and analyzed in 243 patients with acute inferior myocardial infarction who were admitted to the coronary care unit during the years 1987 and 1988. One hundred and ninety-eight patients had no signs of right ventricular involvement (group I), whereas 45 patients had inferior myocardial infarction with right ventricular infarction (group II). Patients were divided into groups depending on the presence or absence of complete atrioventricular block during hospital stay (groups Ia and IIa without block and groups Ib and IIb with block). Selected clinical and laboratory variables were compared for each group. We found that patients with inferior myocardial infarction and complete atrioventricular block had significantly higher mortality rates only in the presence of right ventricular infarction: 41% mortality rate in group IIb versus 11% mortality rate in group Ib (p less than 0.05). Patients with right ventricular infarction but without complete atrioventricular block (group IIa) had a mortality rate similar to that found in patients with inferior myocardial infarction and no atrioventricular block (group Ia): 14% versus 11% (p = NS). In patients with inferior myocardial infarction without right ventricular involvement (group I), complete atrioventricular block did not influence survival: 14% mortality rate in group Ib versus 11% mortality rate in group Ia (p = NS). The excessively high mortality rate in patients who have inferior myocardial infarction with right ventricular involvement and complete atrioventricular block could be the consequence of greater infarct size, but the synergistic influence of right ventricular infarction and complete atrioventricular block could be the other factor that influences outcome.     

急性下壁心肌梗死并心力衰竭的临床特征及预后

目的 :分析急性下壁心肌梗死 (AIMI)并心力衰竭 (心衰 )的临床特征及预后。方法 :记录 180例AIMI患者中并心衰者的临床特征及住院并发症 ,行常规 12导联心电图及右胸导联心电图 ,并与无心衰者比较。结果 :AIMI并心衰者 41例 (占 2 2 .8% )。并心衰组较无心衰组年龄大〔6 5 .3± 10 .8)岁∶ (6 1.1± 10 .1)岁〕、肌酸激酶 (CK)峰值高〔(2 70 0 .4± 2 0 87.7) IU / L∶ (1879.1± 16 0 3.1) IU / L〕,右室梗死 (31.7%∶ 5 .8% )及高度房室传导阻滞 (39.0 %∶ 17.3% )发生率高 ,胸前导联 V4～ 6 ST段压低为主者比例高 (5 6 .1%∶ 2 4.5 % ) ,住院病死率高(4 6 .3%∶ 17.3% )。 L ogistic回归分析显示 AIMI并心衰与 CK峰值、右室梗死、胸前导联 V4～ 6 ST段压低及死亡率独立相关 ,而与年龄及高度房室传导阻滞不相关。结论 :AIMI并心衰者胸前 V4～ 6 导联 ST段压低及右室梗死发生率高 ,CK峰值高。 AIMI并心衰住院病死率高 ,预后差 ,为一高危亚组。     

Effect of coronary artery recanalization on right ventricular function in patients with acute myocardial infarction

The effects of coronary artery recanalization by intracoronary administration of streptokinase on left ventricular function during acute myocardial infarction have received increasing attention in recent years. Although myocardial dysfunction is often more pronounced in the right ventricle than in the left ventricle in patients with acute inferior wall myocardial infarction, the effect of coronary artery recanalization on right ventricular dysfunction has not been previously addressed. Accordingly, in this investigation, 54 patients who participated in a prospective, controlled, randomized trial of recanalization during acute myocardial infarction were studied. Among 30 patients with inferior wall infarction, 19 had right ventricular dysfunction on admission; 11 of these 19 had positive uptake of technetium-99m pyrophosphate in the right ventricle, indicative of right ventricular infarction. Patients with successful recanalization (n = 6) exhibited improved right ventricular ejection fraction from admission to day 10 (26 +/- 7 to 39 +/- 14%, p less than 0.03). However, control patients (n = 6) and patients who did not undergo recanalization (n = 7) also exhibited improvement (20 +/- 7 to 29 +/- 11% [p less than 0.02] and 30 +/- 8 to 40 +/- 6% [p less than 0.03], respectively). Improvement in several other variables of right ventricular dysfunction evolved at an equal rate with the ejection fraction changes. Patients with or without right ventricular infarction improved similarly. These data indicate that the right ventricular dysfunction commonly associated with inferior wall infarction is often transient, and improvement is the rule, irrespective of early recanalization of the "infarct vessel."     

Should inferior myocardial infarction be thrombolysed?]

Recent randomised studies have demonstrated the benefits of administration of intravenous thrombolytic agents in the acute phase of myocardial infarction. Though the benefits are generally acknowledged in cases of anterior wall necrosis, the results in inferior infarction have been discordant. The early patency rate at 90 minutes after thrombolysis is lower in the right coronary and left circumflex than in the left anterior descending artery. The secondary reocclusion rate is twice as high on the right coronary artery. The significant increase in ejection fraction after thrombolysis has only been demonstrated in 2 of the 8 studies in the literature. The benefits in terms of early mortality were not significant in the GISSI study. A significant decrease in early mortality (7.2% vs 8.8%) was observed only in the ISIS 2 study with streptokinase. The reinfarction rate at 1 year was twice as high when the initial infarct was on the inferior wall. Analysis of the results in the literature shows that the benefits of intravenous thrombolysis was clearcut in certain subgroups of inferior infarction: ST elevation in over 3 leads, mirror-image anterior lead changes, very early treatment (before the 3rd hour), complicated infarcts (atrioventricular block, right ventricular extension, hypotension) or in inferior infarcts occurring after previous anterior infarction.     

Patterns of coronary compromise leading to bradyarrhythmias and hypotension in inferior myocardial infarction

BACKGROUND: Occlusion and reperfusion of the acutely occluded right coronary artery may result in abrupt bradycardia and hypotension, attributed to Bezold-Jarisch cardio-inhibitory reflexes arising from the ischemic left ventricle. Given that right ventricular infarction, a result of proximal right coronary artery occlusion, predisposes to bradycardia and hypotension, we hypothesized that proximal right coronary occlusions would be more likely to result in bradycardia-hypotension compared to more distal occlusions. METHODS: In 216 patients with acute inferior myocardial infarction undergoing primary angioplasty of the right coronary artery, we retrospectively analyzed the incidence of bradyarrhythmias and hypotension during occlusion and with reperfusion. RESULTS: Occlusion proximal to the right ventricular branches was identified in 151 (70%) of cases, with occlusions distal but compromising the left ventricular and atrioventricular nodal branches in 65 (30%) others. During occlusion, those with proximal occlusions were more likely to suffer hypotension (41 versus 15%, P=0.0002), advanced atrioventricular block (21 versus 3%, P=0.0008) and hypotension with bradycardia (25 versus 9%, P=0.01). Similarly, reperfusion of proximal occlusions more frequently resulted in abrupt hypotension (42 versus 19%, P=0.002), bradycardia (34 versus 14%, P=0.004) and hypotension with bradycardia (27 versus 12%, P=0.02). CONCLUSIONS: These data demonstrate that during right coronary artery occlusion and with reperfusion, bradycardia and hypotension develop more commonly in patients with proximal occlusions compared with those with distal occlusions. These findings suggest that reflexes arising from the ischemic right ventricle may play a role in bradyarrhythmias and hypotension.     

Eligibility for and benefit of thrombolytic therapy in inferior myocardial infarction: Focus on the prognostic importance of right ventricular infarction

Objectives. This study was undertaken to determine eligibility for and benefit of thrombolytic therapy in patients with acute inferior myocardial infarction with or without right ventricular involvement.Background. Right ventricular involvement commonly complicates acute inferior myocardlal infarction and is considered to have prognostic relevance. We hypothesized that the presence of right ventricular infarction, diagnosed early by ST segment elevation in the right precordial lead (V₄R), may be of clinical importance in identifying patients who will benefit most from thrombolytic therapy.Methods. We studied 200 consecutive patients with acute inferior myocardial infarction to assess the prognostic impact of right ventricular infarction in those considered eligible or ineligible for reperfusion therapy. Prognostic analyses were based on the in-hospital period and a 1- to 6-year follow-up (mean [±SD] 37 ± 12 months).Results. ST segment elevation in lead V₄R was a reliable marker of right ventricular infarction (sensitivity 88%, specificity 78%, diagnostic efficiency 83%) in 107 patients (54%) with inferior myocardial infarction. Seventy-one eligible patients (36%) received thrombolytic therapy and had a lower mortality (8% [6 of 71]) and complication (31% [22 of 71]) rate than ineligible patients (mortality rate 25% [32 of 129], p < 0.001; complication rate 56% [72 of 129], p < 0.01). However, the overall benifit of thrombolysis was restricted to patients with right ventricular infarction complicating acute inferior myocardial infarction (with vs. without thrombolysis, respectively: mortality rate 10% vs. 42%, p < 0.005; complication rate 34% vs. 54%, p < 0.05). In the absence of right ventricular infarction, no difference was observed in the mortality (7% vs. 6%, p = NS) and major in-hospital complication (27% vs. 29%, p = NS) rates, whether or not the patient underwent thrombolytic therapy. Posthospital course over 37 ± 12 months was not different in patients with and without right ventricular infarction but was best in all patients considered for reperfusion therapy.Conclusions. During acute inferior myocardial infarction, the right precordial electrocardiogram is a simple but promising variable to identify a subgroup of patients with an unfavorable course who will benefit most from thrombolytic therapy.     

Right ventricular infarction: unusual electrocardiographic and electrophysiological manifestations

Right ventricular infarction occurs in 19-43% of patients with acute inferior wall infarction (Lorell et al., 1979). Its clinical, hemodynamic, and anatomic features are well known and include associated inferior wall infarction, distended neck veins, clear lung fields, hypotension, and heart block (Cintron et al., 1981; Coma-Canella et al., 1979; Lloyd et al., 1981; Lopez-Sendon et al., 1981; Raabe and Chester, 1978; Rotman et al., 1974). Isolated right ventricular infarction is less frequent and occurs in 2.5-4.6% of autopsy studies of myocardial infarction (Cohn et al., 1974; Erhardt et al., 1976; Wartman and Hellerstein, 1948). This report describes a patient with isolated right ventricular infarction with unusual electrophysiological findings. Her initial electrocardiogram showed atrial escape rhythm with incomplete right bundle-branch block and left posterior hemiblock. Later, she developed atrioventricular (AV) block with supra- and infra-Hisian, "phase 4," conduction defects. The sinus malfunction and high degree AV block persisted over 2 weeks and an atrioventricular sequential pacemaker was implanted. Hymodynamic study showed that her cardiac output was highly dependent on the heart rate and properly timed AV interval, and the pacemaker was programmed accordingly.     

Temporal electric stimulation and right ventricular extension in acute postero-inferior myocardial infarction. Influence on clinical characteristics and prognosis]

In 386 patients with acute inferior myocardial infarction (AIMI) who were admitted to our institution from 1984 to 1990, temporary pacemaker (TP) was required in 34 patients (9%) due to disturbances in the genesis and/or conduction of the electric stimulus (Group I). The remainder, 352 AIMI, conform the Group II. Each group was divided into groups depending on the presence (Groups Ia and IIa) or absence (Groups Ib and IIb) of right ventricular necrosis (ECG criteria: ST elevation greater than 0.1 mV in a V3r and V4R). Clinical data (cardiovascular risk factors, history of myocardial infarction or angina, CPK and CK-MB peak, Killip class, atrioventricular block and right ventricular infarction) and hospital mortality rate and its cause were analyzed. The Group I patients related to Group II had significantly higher diabetes rate (p less than 0.01), CPK and CK-MB peak (p less than 0.001), Killip class (p less than 0.001), right ventricular involvement and atrioventricular block (p less than 0.001), the mortality rate equally was statistically higher (Group I, 11 patients, 31%, versus group II, 38 patients, 11%) (p less than 0.001). The Group Ia patients related to Group Ib had a higher CPK and CK-MB peak (p less than 0.001), Killip class and atrioventricular block (p less than 0.001). The mortality rate was statistically equal. The group IIb patients related to Group IIb patients had a higher CPK and CK-MB peak (p less than 0.001), without differences in the mortality rates.(ABSTRACT TRUNCATED AT 250 WORDS)     

The incidence, clinical characteristics and prognostic significance of a left bundle-branch block associated with an acute myocardial infarct

To assess the current incidence and meaning of left bundle-branch block associated with acute myocardial infarction we studied 1,239 patients consecutively admitted in three hospitals. Left bundle branch block was present in 42 cases (3.3%). Compared to the patients without left bundle-branch block, those with left bundle-branch block were older (70 +/- 8.8 versus 63.9 +/- 11.4 years; p < 0.001), and had a more prevalent history of diabetes, angina, myocardial infarction and heart failure. Left bundle-branch block was associated more frequently with female gender and poor left ventricular ejection fraction. Patients with left bundle branch block were admitted with a longer interval from the onset of the symptoms (7.8 +/- 6.3 versus 5.4 +/- 6.7 hours; p < 0.01) and received in a lesser rate thrombolytics agents (21% versus 56%; p < 0.001), than those without left bundle-branch block. Complications significatively associated with left bundle-branch block were: complete AV block; heart failure and one-year mortality (40.4% versus 19.5%, p < 0.01). Female gender, age and heart failure were independent predictors of mortality whereas left bundle-branch block was not. In conclusion, current incidence of left bundle-branch block in acute myocardial infarction is lower than that referred in the pre-thrombolytic era. Left bundle-branch block is accompanied by a low rate of thrombolysis, whereas a higher mortality rate of these patients seems to depend on their clinical characteristics.     

Antecedent angina pectoris as a predictor of better functional and clinical outcomes in patients with an inferior wall acute myocardial infarction

We examined whether angina pectoris (AP) occurring shortly before the onset of acute myocardial infarction (AMI) can render the right ventricle and the conducting tissue resistant to ischemia in 75 patients with an inferior wall AMI. Each patient had total occlusion in the proximal right coronary artery and underwent successful coronary angioplasty < or =24 hours from the onset. We divided patients into 2 groups based on presence or absence of antecedent AP < or =24 hours before the system onset: group 1 (absent) = 57 patients; group 2 (present) = 18 patients. Collateral circulation was more frequently observed in group 2 than in group 1 (group 1 vs 2, 28% vs 61%, p <0.01). Elevation in ST segment > or =1 mm in lead V4R, hemodynamic right ventricular dysfunction, and frequency of high-degree heart block were more frequent in group 1 than in group 2 (75% vs 44%, 79% vs 39%, 53% vs 11%, p <0.05, respectively). Multivariate analysis demonstrated that antecedent AP is the only factor related to these complications. Thus, episodes of AP occurring shortly before onset may restrain development of ischemic damage of the right ventricle and conducting tissue, and are associated with better clinical and functional outcomes among patients with an inferior wall AMI.     

心电图J／R比值对下壁心肌梗死并发房室阻滞的预测价值

目的探讨急性下壁心肌梗死早期心电图表现对高度房室阻滞的预测价值以及与冠状动脉病变的关系。方法分析97例急性下壁心肌梗死患者早期心电图（下壁导联）J／R≥0．5的发生情况，部分病例结合冠脉造影结果，探讨其对房室阻滞的预测价值。结果27例（21．6％）在心肌梗死急性期发生二度以上房室阻滞。有房室阻滞者，心电图下壁导联J／R≥0．5多于无房室阻滞者（69．56％vs30．44％，p〈0．01）。冠状动脉造影显示，有房室阻滞者，右冠状动脉近中段的高度狭窄明显多于无房室阻滞者（100％vs58．33％）。结论急性下壁心肌梗死伴房室阻滞者的病损冠脉以右冠状动脉多见，下壁导联心电图J／R≥0．5对下壁心肌梗死合并房室阻滞的发生有一定的预测价值。     

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.     

Right ventricular myocardial infarction in patients with chronic lung disease: possible role of right ventricular hypertrophy

To determine the relation between right ventricular hypertrophy and right ventricular myocardial infarction in patients with chronic lung disease, the records of 28 patients with chronic lung disease, inferior myocardial infarction and significant coronary artery disease (group I) and 20 patients with right ventricular hypertrophy, chronic lung disease without inferior myocardial infarction or significant coronary artery disease (group II) were reviewed. Chronic lung disease was diagnosed by clinical criteria, chest radiographs and pulmonary function tests. All patients had postmortem examinations. Patients in group I were classified into two subgroups: group Ia (without right ventricular hypertrophy) and group Ib (with right ventricular hypertrophy). Right ventricular wall thickness was 3.3 mm +/- 0.5 in group Ia, 6.0 mm +/- 1.1 in group Ib and 8.8 mm +/- 2.4 in group II (group Ia versus Ib, p less than 0.001; group Ia versus II, p less than 0.001; group Ib versus II, p less than 0.001). Eleven patients (78.6%) in group Ib (chronic lung disease with both right ventricular hypertrophy and inferior myocardial infarction) had right ventricular myocardial infarction compared with only 3 patients (21.9%) in group Ia (chronic lung disease without right ventricular hypertrophy and with inferior myocardial infarction) (p less than 0.008). Isolated right ventricular myocardial infarction occurred in four patients (20%) in group II (chronic lung disease with right ventricular hypertrophy, but without evidence of infarction of the left ventricle or significant coronary artery disease). There was no significant difference in the extent of anatomic coronary disease in groups Ia and Ib.(ABSTRACT TRUNCATED AT 250 WORDS)     

An unusual presentation of massive pulmonary embolism mimicking septal acute myocardial infarction treated with tenecteplase

A 31-year-old man (175 cm, 82 kg) was referred to the emergency department 2 h after the sudden onset of acute dyspnea. Immediate ECG showed sinus tachycardia with ST elevations from V1 through V2 and a diagnosis of septal acute myocardial infarction was made. ECG on admission to the cardiology department showed the same results plus the S1–Q3–T3 pattern. Echocardiogram revealed a normally contracting left ventricle, a distended right ventricle with free wall hypokinesia and displacement of the interventricular septum towards the left ventricle. Thrombolytic therapy with tenecteplase 8000 IU and heparin 5000 IU was administered 5–10 min after hospitalisation and the patient was haemodynamically stable 30 min later. Echocardiogram performed 12 h after thrombolysis showed a normal left ventricle and a less distended right ventricle. Lung spiral computed tomography (CT) and lower abdominal CT on the fourth day showed large emboli in the inferior pulmonary arteries of the right and left lung. Rarely, massive pulmonary embolism may mimic anteroseptal acute myocardial infarction on ECG and this case demonstrates the utility of echocardiography for a differential diagnosis, as well as the efficacy of tenecteplase for thrombolytic therapy.     

Angiographic correlates of anterior ST segment depression in acute inferior wall myocardial infarction.

This study was conducted prospectively to assess the correlation between the pattern of anterior ST segment depression on the admission electrocardiogram and the in-hospital morbidity and mortality in patients with acute inferior wall myocardial infarction. Coronary angiography was also done to assess its correlation, if any, with pattern of anterior ST segment depression. Our study cohort comprised of 165 consecutive patients with acute inferior wall myocardial infarction divided into four groups based on admission electrocardiogram. Group I (n = 33): patients with no anterior ST segment depression; group II (n = 16): patients with ST segment depression in leads V1-V3; group III (n = 71): patients with ST segment depression in leads V4-V6, I and aVF, and; group IV (n = 45): patients with ST segment depression in all anterior leads (V1-V6, I, aVL). The outcomes were analysed in terms of high grade atrioventricular block, Killip class II or higher failure, and in-hospital mortality. Coronary angiography was performed to analyse coronary anatomy. Group IV patients had increased incidence of complete heart block (37.8% vs 15.2% in the total group) (p < 0.001) and increased mortality (11.1% vs 4.2% in the total group) (p < 0.05). This group also had greater incidence of triple vessel disease (76.7%) (p < 0.001). Group II patients had greater incidence of double vessel disease (88.9%) (p < 0.05) and had no triple vessel disease. Group III patients had double vessel disease (76.5%) (p < 0.05) or triple vessel disease (23.5%) (p = NS) and no single vessel disease. Coronary angiography in group II showed greater incidence of involvement of left circumflex artery and right coronary artery while in group III there was left anterior descending artery and right coronary artery disease. We conclude that patients with anterior ST segment depression in group III and group IV categories are in high risk subset with acute inferior wall myocardial infarction.     

Inferior ST segment changes during acute anterior myocardial infarction: a marker of the presence or absence of concomitant inferior wall ischemia

The significance of inferior ST segment changes during acute anterior myocardial infarction was studied in 60 patients with acute anterior infarction who had angiographic visualization of the entire distribution of the left anterior descending artery after thrombolytic therapy with streptokinase. In 34 patients (Group 1) this artery supplied the anterior wall of the left ventricle up to or including the apex but did not reach the inferior wall; in 16 patients (Group 2) it continued beyond the apex onto the inferior wall of the left ventricle; and in 10 patients with prior inferior infarction (Group 3) it partially supplied the inferior wall of the left ventricle through collateral channels to an occluded right or dominant circumflex coronary artery. Consistent with this anatomy, evidence of inferior wall ischemia was significantly more frequent in Groups 2 and 3 than in Group 1 by thallium-201 scintigraphy (91 versus 7%) and by contrast left ventriculography (91 versus 13%). There was no difference in the magnitude of precordial ST segment elevation among the three groups but the inferior ST segment depression was significantly smaller in Groups 2 and 3 with concomitant inferior wall ischemia than in Group 1 (aVF: -0.5 +/- 0.7; -0.5 +/- 1.0; -1.8 +/- 0.8 mm, respectively; p less than 0.001) with 10 of the 26 patients in Groups 2 and 3 having an elevated or isoelectric ST segment in aVF compared with none of the 34 patients in Group 1 (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Bedside recognition,incidence and clinical course of right ventricular infarction

To evaluate the incidence, clinical characteristics and course of right ventricular infarction, 96 patients with an established diagnosis of acute myocardial infarction were evaluated during a 10 month study period. Of the 44 patients with acute inferior wall myocardial infarction, 16 had bedside evidence of right ventricular dysfunction. All had a positive Kussmaul's sign, and 12 had either a right ventricular third or fourth heart sound. Inspiratory elevation of right atrial and right ventricular end-diastolic pressures was documented in nine patients. Ventricular fibrillation developed in one patient and advanced atrioventricular block in three. All 16 patients survived and were alive 3 months after infarction. The hospital course and 3 month survival rate were not different from those of the usual patient with inferior wall infarction. Approximately one third of the patients with inferior wall myocardial infarction have bedside evidence of right ventricular infarction, which usually does not alter short-term prognosis.     

Duration of complete atrioventricular block complicating inferior wall infarction treated with fibrinolysis

INTRODUCTION AND OBJECTIVES: The aim of this study was to determine the duration of complete atrioventricular block complicating inferior wall acute myocardial infarction after the administration of fibrinolytic therapy. PATIENTS AND METHOD: From 1 January 1992 to 31 January 2002 a total of 449 patients were admitted directly to our hospital with inferior wall acute myocardial infarction in the first 6 hours; 282 of them (64%) received fibrinolytic therapy. Complete atrioventricular block appeared in 39 of these 282 patients (13.8%, group A). Of the 167 patients who did not receive thrombolytic therapy, complete atrioventricular block appeared in 13 (8%, control group). We compared the two groups by analyzing the duration of heart block, time to appearance, hemodynamic repercussion, and treatment required. RESULTS: On admission, 38% of the patients in group A and 61% (P=NS) of those in the control group had complete atrioventricular block. Median duration of the block was 75 minutes (10 minutes to 48 hours) in group A and 24 hours (15 minutes to 9 days) in the control group (P=.004). After fibrinolytic therapy was administered, median duration of the block was 45 minutes (5 minutes to 48 hours). A temporary pacemaker was implanted in 43% of the group A patients and 84.6% of the control group patients (P=.01). CONCLUSION: Complete atrioventricular block appears as a complication of inferior myocardial infarction within the first hours after the event. Duration of the block seems to be shorter in patients treated with fibrinolytic therapy.     

Clinical and angiographic outcome of patients with acute inferior myocardial infarction

OBJECTIVES: This study sought to determine the procedural success and the in-hospital outcome after primary coronary angioplasty in patients with acute inferior myocardial infarction and right ventricular involvement (RVI). BACKGROUND: RVI represents an easily detectable, highly prevalent subset of acute inferior infarction associated with poor outcome even in the era of thrombolysis. Primary PTCA may offer advantages in patients with inferior infarction involving the right ventricle. METHODS: Primary coronary angioplasty with optimal stenting was performed in 87 of 88 consecutive patients presenting within 24 hours after onset of acute inferior myocardial infarction. On the basis of right precordial ST segment elevations at admission, patients were classified into those without (n=61) and those with RVI (n=27). The patients were followed prospectively for angiographic success at 10 days and for in-hospital clinical outcome. RESULTS: Baseline characteristics including age, severity of coronary artery disease, proportion of stent implantation, and occurrence of cardiogenic shock were comparable. Patients with RVI had larger infarct sizes (lactate dehydrogenase level: 962 vs 580 U/l, P=0.03), developed more often complete atrioventricular block (18.5 vs. 2%, p=0.0038), needed more often parasympatholytics (48.1 vs 18.8%, p<0.001), and had a substantially higher incidence of the Bezold-Jarisch reflex (29.6 vs 6.6%, p<0.01) following reperfusion.Success of recanalization therapy acutely and at 10 days, as well as in hospital mortality were similar in patients with and without RVI (88.5 vs. 85.2%, 79.3 vs. 84.7%, 7.4 vs 9.8%). However, patients with RVI revealed a greater lumen gain acutely after PTCA (2.49 vs. 2.13 mm, p=0.025) and experienced less frequently major cardiac events (14.8 vs. 36.1%, p=0.04) which included reinfarction, re-ischemia, coronary bypass grafting, stent thrombosis, and cardiac death. In addition, procedural success was established more rapidly (fluoroscopy time: 10 vs 15 min., p=0.032) and with less contrast material (242 vs 295 ml, p=0.015) in patients with RVI. This is probably due to the more proximal location (84.6 vs 6.6%, p<0.0001) and the larger reference diameter (3.17 vs. 2.79 mm, p=0.03) of the occluded right coronary artery. CONCLUSIONS: Primary PTCA is an appropriate reperfusion strategy in patients with RVI. Further comparative studies are required to compare the effectiveness of primary PTCA with early thrombolytic therapy in this high risk setting.     

The distinction between coronary and myocardial reperfusion after thrombolytic therapy by clinical markers of reperfusion

Objectives. We sought to examine the hypothesis that rapid resolution of ST-segment elevation in acute myocardial infarction (AMI) patients with early peak creatine kinase (CK) after thrombolytic therapy differentiates among patients with early recanalization between those with and those without adequate tissue (myocardial) reperfusion.Background. Early recanalization of the epicardial infarct-related artery (IRA) during AMI does not ensure adequate reperfusion on the myocardial level. While early peak CK after thrombolysis results from early and abrupt restoration of the coronary flow to the infarcted area, rapid ST-segment resolution, which is another clinical marker of successful reperfusion, reflects changes of the myocardial tissue itself.Methods. We compared the clinical and the angiographic results of 162 AMI patients with early peak CK (≤12 h) after thrombolytic therapy with (group A) and without (group B) concomitant rapid resolution of ST-segment elevation.Results. Patients in groups A and B had similar patency rates of the IRA on angiography (anterior infarction: 93% vs. 93%; inferior infarction: 89% vs. 77%). Nevertheless, group A versus B patients had lower peak CK (anterior infarction: 1,083 ± 585 IU/ml vs. 1,950 ± 1,216, p < 0.01; and inferior infarction: 940 ± 750 IU/ml vs. 1,350 ± 820, p = 0.18) and better left ventricular ejection fraction (anterior infarction: 49 ± 8, vs. 44 ± 8, p < 0.01; inferior infarction: 56 ± 12 vs. 51 ± 10, p = 0.1). In a 2-year follow-up, group A as compared with group B patients had a lower rate of congestive heart failure (1% vs. 13%, p < 0.01) and mortality (2% vs. 13%, p < 0.01).Conclusions. Among patients in whom reperfusion appears to have taken place using an early peak CK as a marker, the coexistence of rapid resolution of ST-segment elevation further differentiates among patients with an opened culprit artery between the ones with and without adequate myocardial reperfusion.