Early atrial arrhythmias in acute myocardial infarction. Role of the sinus node artery.

We studied atrial arrhythmias during the first 12 h of admission to the hospital in 266 consecutive patients with acute myocardial infarction who subsequently underwent coronary angiography. Ten patients developed atrial fibrillation, one atrial flutter, and one supraventricular tachycardia. Another five developed sinus dysrhythmias. All of the above patients had an acute inferior myocardial infarction, and in 10 of the 12 patients with supraventricular arrhythmias and in four of five with sinus dysrhythmias, the origin of the sinus node artery started just after an occluded right coronary or left circumflex artery or was involved in the occlusion. Thus, ischemia of the sinus node due to coronary occlusion proximal to the origin of the sinus node artery was a likely cause of these arrhythmias.     

Conduction disturbances and paroxysmal atrial fibrillation during acute inferior myocardial infarction

Associated symptoms and conduction disturbances are reported during acute inferior myocardial infarction. Differentiation of right coronary artery from left circumflex artery occlusion may be difficult since both can present an electrocardiographic pattern of inferior myocardial infarction. Paroxysmal atrial fibrillation is considered a frequent complication of acute myocardial infarction and the patients with paroxysmal atrial fibrillation probably should be targeted for earlier and more aggressive treatment. These patients in the thrombolytic era have a better overall outcome than counterparts in the prethrombolytic era. We describe a case of conduction disturbances and paroxysmal atrial fibrillation in a 51-year-old Italian man with acute inferior myocardial infarction and right coronary artery stenosis.     

Conversion of infarction-associated atrial fibrillation by restoration of atrial perfusion

We report a patient who presented with new onset atrial fibrillation in the setting of inferior ST-segment elevation myocardial infarction (STEMI). Cardiac catheterization revealed proximal occlusion of the left circumflex artery. Balloon angioplasty and stenting restored flow to a large left atrial branch, with prompt conversion of the rhythm to atrial flutter, and then to sinus rhythm. To our knowledge this represents the first demonstration of restoration of sinus rhythm by reversing left atrial ischemia in the setting of STEMI.     

急性下壁心肌梗死患者心电图胸前导联ST段改变的临床意义

目的探讨急性下壁心肌梗死患者心电图胸前导联ST段改变与冠状动脉造影(CAG)所见冠状动脉病变部位的关系及其临床意义。方法 187例急性下壁心肌梗死患者,按入院时18导心电图胸前导联ST段改变分为3组,ST段无变化组(47例),ST段抬高组(16例),ST段压低组(124例);所有患者均行CAG。结果急性下壁心肌梗死伴胸前导联ST段抬高时多为右冠状动脉(RCA)近段闭塞(14例,82.3%),尤其是伴圆锥支动脉闭塞,与RCA中远端闭塞(2例,5.9%)比较差异有统计学意义(P0.01),且14例(73.7%)伴有右心功能不全和血流动力学障碍。下壁心肌梗死胸前导联ST段压低者可见于RCA、回旋支(LCX)闭塞及RCA、LCX闭塞与前降支(LAD)、对角支(D)病变的不同组合,其中LCX闭塞伴RCA病变者多表现为朐前ST V_4～V_6的压低,RCA闭塞伴LAD近端病变多有胸前ST V_1～V_6的压低,RCA伴D病变胸前ST V_1～V_3压低,与对照组比较差异有统计学意义(P0.05)。结论急性下壁心肌梗死合并胸前导联ST段抬高表明为RCA近段或丌口闭塞且多伴右心室心肌梗死和心功能不全;下壁心肌梗死伴胸前导联ST段压低提示为多支病变,ST V_1～V_3压低多伴有对角支严重狭窄,STV_1～V_6压低多伴有前降支的严重狭窄。     

Complications of emergency coronary angioplasty for acute myocardial infarction]

To assess the incidence and consequences of complications occurring during emergency percutaneous transluminal coronary angioplasty (PTCA) for acute myocardial infarction (AMI), we studied 347 patients who underwent PTCA within 24 hours after the onset of AMI. Acute occlusion occurred in 29 patients (8.4%), of whom 16 patients underwent successful repeat PTCA. All of them survived until hospital discharge. The in-hospital reocclusion rates of these 16 patients were comparable to those of patients who had not experienced acute occlusion (18.8 vs 12.8%, ns). In the remaining 13 patients, reperfusion were not successful after acute occlusion, and 6 died. Side branch occlusion occurred in 21 patients (6.1%). Left circumflex artery occlusion occurring during PTCA for the proximal left anterior descending artery was fatal in 3 patients. Right ventricular branch occlusion during PTCA for the middle of the right coronary artery resulted in intractable right ventricular infarction in one patient, and he died. Among 14 patients who underwent repeat angiography, 13 had a patent side branch which had been occluded during PTCA. One patient had coronary rupture and died. During PTCA of the proximal left anterior descending artery, acute occlusion of the artery without reperfusion or occlusion of the left circumflex artery was often fatal. However, the prognosis of acute occlusion was relatively good, if repeat PTCA was successful and most of the occluded side branches remained patent in the chronic state.     

急性心肌梗死患者Ⅲ度房室传导阻滞与房室结动脉血供的关联性

目的 观察和分析急性心肌梗死(AMI)患者Ⅲ度房室传导阻滞(AVB)与房室结动脉血供的关系。方法 将入选的AMI患者,按是否并发Ⅲ度AVB分为两组:病例组为AMI并发Ⅲ度AVB的患者（n=35例）,对照组为AMI未并发Ⅲ度AVB的患者（n=215例）,通过观察梗死相关动脉并分析房室结动脉血供来源情况,分析AMI患者不同房室结动脉血供来源发生Ⅲ度AVB的几率,并观察AMI并发Ⅲ度AVB的患者,房室结动脉血运改善后Ⅲ度AVB恢复时间。结果 房室结动脉血供来源于右冠状动脉的右上降支动脉和回旋支的kugel’s动脉之一或二者双重血供。病例组患者,其房室结动脉血供仅来源于右冠状动脉的右上降支或回旋支的kugel’s动脉,无前降支来源,并且右冠状动脉较回旋支多见（P<0.01）。当梗死相关动脉得到再灌注,恢复血运后,AVB均恢复到窦性心律。结论 急性心肌梗死Ⅲ度AVB发生患者与其房室结动脉血供中断有关,恢复房室结动脉血供后AVB恢复窦性心律。     

急性下壁ST段抬高心肌梗死直接冠脉内支架置入术靶血管判定及预后评估

目的 总结急诊介入治疗（PCI）的急性下壁心肌梗死患者心电图及临床资料,分析其对急性下壁心肌梗死患者罪犯血管判定及预后评估的作用.方法 选择2007年1月到2010年7月进行急诊PCI的急性下壁心肌梗死患者280例,根据冠脉造影结果分为右冠状动脉（RCA）梗死组及左冠回旋支（LCX）梗死组;根据临床结果分为高危急性下壁心梗组（高危组）及低危组.分析各组的心电图表现、危险因素及预后.结果 RCA组与LCX组比较,STⅢ＞STⅡ、STavL或STⅠ＞1 mm下移更多见于RCA梗死.高危组年龄比低危组偏大,糖尿病患者更多,更多出现心肌梗死溶栓治疗（TIMI）分级中的0级（无灌注）及1级（渗透而无灌注）,RCA近端闭塞及双支、三支病变患者,心电图出现STV3R-5R↑、STV7-V9↑、STV4-6↓、STV1↑、STAVR↓的比例更高.结论 心电图在急性下壁心肌梗死进行急诊PCI的患者诊断及预后判断中有重要作用,对进行急诊PCI靶血管判定有一定的协助作用.冠脉造影TIMI 0、1级,RCA近端闭塞,双支、三支病变患者,年龄偏大患者和糖尿病患者整体预后均较差.     

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.     

Site of myocardial infarction. A determinant of the cardiovascular changes induced in the cat by coronary occlusion.

The influence of site of acute myocardial infarction on heart rate, blood pressure, cardiac output, total peripheral resistance (TPR), cardiac rhythm, and mortality was determined in 58 anesthetized cats by occlusion of either the left anterior descending (LAD), left circumflex or right coronary artery. LAD occlusion resulted in immediate decrease in cardiac output, heart rate, and blood pressure, an increase in TPR, and cardiac rhythm changes including premature ventricular beats, ventricular tachycardia, and occasionally ventricular fibrillation. The decrease in cardiac output and increase in TPR persisted in the cats surviving a ventricular arrhythmia. In contrast, right coronary occlusion resulted in a considerably smaller decrease in cardiac output. TPR did not increase, atrioventricular condition disturbances were common, and sinus bradycardia and hypotension persisted in the cats recovering from an arrhythmia. Left circumflex ligation resulted in cardiovascular changes intermediate between those produced by occlusion of the LAD or the right coronary artery. Mortality was similar in each of the three groups. We studied the coronary artery anatomy in 12 cats. In 10, the blood supply to the sinus node was from the right coronary artery and in 2, from the left circumflex coronary artery. The atrioventricular node artery arose from the right in 9 cats, and from the left circumflex in 3. The right coronary artery was dominant in 9 cats and the left in 3. In conclusion, the site of experimental coronary occlusion in cats is a major determinant of the hemodynamic and cardiac rhythm changes occurring after acute myocardial infarction. The cardiovascular responses evoked by ligation are related in part to the anatomical distribution of the occluded artery.     

Compromised atrial coronary anatomy is associated with atrial arrhythmias and atrioventricular block complicating acute myocardial infarction

BACKGROUND: The relevance of the atrial coronary anatomy in the pathogenesis of atrial arrhythmias and atrioventricular (AV) block complicating acute myocardial infarction (AMI) remains unclear. OBJECTIVES: We evaluated the location of the infarct-related coronary lesion relative to the principal atrial branches (ie, sinoatrial nodal, AV nodal, left atrial circumflex) in 454 patients with ST-elevation AMI in the CAPTORS II trial. METHODS: Patients underwent systematic 60-minute postfibrinolytic angiograms, and coronary anatomy was correlated with evidence of atrial arrhythmias and AV block on sequential electrocardiograms. RESULTS: Patients with either sinoatrial nodal or left atrial circumflex compromise (n = 34) had a higher incidence of "early" (ie, up to 90 minutes postfibrinolysis) atrial arrhythmias vs those without (23.5% vs 7.1%; P = .004). Patients with AV nodal compromise (n = 207) had a higher incidence of "early" AV block vs those without (12.1% vs 3.6%; P = .001). CONCLUSION: These findings support the etiological role of acute atrial ischemia in the development of early atrial arrhythmias and AV block complicating AMI.     

Angioplasty in total coronary artery occlusion

Percutaneous transluminal coronary angioplasty was attempted without streptokinase in 24 patients with total coronary artery occlusion but without acute transmural myocardial infarction. The maximal duration of occlusion was estimated to be 1 week or less in 10 patients, more than 1 to 4 weeks in 6, more than 4 to 12 weeks in 3 and more than 12 weeks in 5. Dilation of the occluded artery was attempted in the left anterior descending coronary artery in 17 patients, in the right coronary artery in 4 and in the circumflex coronary artery in 3. Angioplasty was successful in 13 patients (54%): left anterior descending coronary artery in 59%, right coronary artery in 50% and circumflex coronary artery in 33%. In patients with successful dilation, there was a mean decrease in coronary artery stenosis from 100 to 23%. In the 19 patients whose occlusion was estimated to be of 12 weeks' duration or less, angioplasty was successful in 68%. In the five patients whose occlusion was estimated to be of more than 12 weeks' duration, dilation was not successful in any (p = 0.006). It is concluded that in selected patients with symptomatic coronary artery disease and recent coronary artery occlusion without associated acute myocardial infarction, percutaneous transluminal coronary angioplasty alone may be effective in restoring patency.     

Evaluation of electrocardiographic algorithms in the assessment of the infarct-related artery in acute myocardial infarction

OBJECTIVES: In acute myocardial infarction, it is of great value to identify the infarct-related artery and the site of occlusion in a coronary artery (proximal versus distal).This study assessed the diagnostic value of two previously published electrocardiographic algorithms to identify the infarct-related artery and the site of occlusion in anterior and inferior acute myocardial infarction. METHODS AND RESULTS: We studied retrospectively a group of 88 patients with a first myocardial infarction. We determined the infarct-related artery using the electrocardiographic algorithms on the electrocardiogram at the time of admission and compared these results with the angiographically determined infarct-related artery. The best electrocardiographic algorithm could determine the infarct-related artery in an inferior myocardial infarction as the left circumflex coronary artery and as the proximal and distal right coronary artery with a sensitivity of 63%, 67% and 80%, respectively, and a specificity of 100%, 82% and 69%, respectively. One algorithm was unable to diagnose a left circumflex coronary artery occlusion. In an anterior myocardial infarction the best electrocardiographic algorithm could determine the infarct-related artery as the proximal and distal left anterior descending coronary artery with a sensitivity of 85% and 80%, respectively, and with a specificity of 77% and 82%, respectively. CONCLUSION: In acute myocardial infarction the use of electrocardiographic algorithms is helpful to predict the site of occlusion and can play a crucial role in the care of patients.     

Transcoronary chemical ablation of atrioventricular conduction

In seven patients with symptomatic atrial fibrillation and uncontrollable ventricular rates, selective catheterization of the atrioventricular (AV) nodal artery was performed to chemically destroy the AV node. Ethanol at a concentration of 96% and a dose of 0.5-2 ml was used after selective catheterization of the AV nodal artery had demonstrated temporary AV block after the administration of isotonic iced saline. Complete AV block was produced in five patients and AV conduction was sufficiently modified to control symptoms in the remaining two patients. A minimal enzyme rise occurred in six patients. A severe complication in the remaining patient occurred when, after 2 ml ethanol in the AV nodal artery, occlusion developed in the midright coronary artery that led to an inferior wall myocardial infarction. It is concluded that the AV nodal artery can be selectively catheterized using presently available angioplasty techniques. Ethanol can be used to destroy the AV node and block AV conduction.     

Stenosis in a coronary collateral artery--a case report

The coronary cineangiography of a man with an inferoposterior myocardial infarction is reported. An occlusion of the proximal right coronary artery and an occlusion at the origin passing around the left atrial wall of the circumflex artery was observed. A large collateral artery connected the right coronary artery and the distal circumflex artery. This vessel showed a significant stenosis of 70%. This case suggests that collateral arteries are not protected from atherosclerotic degeneration. Alternatively, since the exact caliber of the anastomosis before the occlusion of the recipient artery is not known, an extrinsic compression or kinking may have generated the stenosis at the time of the flow-related dilatation of the vessel.     

Coronary artery dissection following radiofrequency ablation for atrial fibrillation: Case report and review of the literature

Coronary artery injury following catheter ablation for cardiac arrhythmias is very rare. We present a case of left circumflex (LCx) coronary artery dissection causing inferoposterior ST-elevation myocardial infarction following radiofrequency (RF) ablation for atrial fibrillation (AF) in a 39-year-old male with no cardiovascular risk factors. This was confirmed on coronary angiography and intracoronary vascular ultrasound (IVUS). The likely etiology is thermal injury during RF ablation for AF, due to the close proximity of the left atrial appendage and left pulmonary veins to the LCx. He was successfully treated with primary percutaneous coronary intervention with good outcome. This is, to our knowledge, the first reported case of proven acute coronary dissection secondary to RF ablation for AF reported in the literature, and highlights the importance of considering this as a mechanism for coronary occlusion in these patients.     

Infarctus du myocarde secondaire à l’occlusion aiguë simultanée des portions proximales de la circonflexe et de la coronaire droite : à propos d’un cas

Acute myocardial infarction due to simultaneous occlusion of two major coronary arteries is a rare phenomenon. We report a case of a 53-year-old man with many cardiovascular risk factors, who presented to the emergency with an acute coronary syndrome with ST segment elevation in anterior and inferior leads, complicated by atrioventricular block and cardiogenic shock. The coronary angiogram showed proximal occlusion of left circumflex artery and right coronary artery. Both arteries were treated successfully with thrombectomy followed by coronary stent implantation. Some similar cases have been reported, but the exact physiopathological mechanism is unknown. There is no clear strategy established for the therapeutic coverage, however, percutaneous revascularisation seems to be actually appropriated treatment.     

Anterior ST-segment deviation during inferior myocardial infarction: arteriographic correlations during the acute phase

Electrocardiographic changes in the anterior wall lead in inferior myocardial infarction were studied in coronary angiographic findings in the acute stage. The subjects were 40 patients with initial inferior myocardial infarction due to right coronary lesions. ST segments were elevated in 7 patients, remained unchanged in 11 and were depressed in 22. Two patients predominantly perfused in the left coronary artery showed ST elevation. All seven patients who showed elevation of the ST segments had occlusion of the ventricular branch proximal to right. However, another 15 (68%) of the patients with occlusion of the same lesion did not show elevation of any ST segment. There was no difference in left ventricular ejection fraction between the groups. The regional ejection fraction at the left ventricular inferior wall was significantly (p less than 0.01) higher in the ST elevated group than in the ST depressed group. Elevation of the ST segments in the anterior wall lead was observed only when the right ventricular free wall sustained injury, and no elevation of any ST segment was observed when the range of injury in the inferoposterior wall was wide, even in the presence of injury to the right ventricular free wall.     

The necessary conditions of chronic total occlusion of all three coronary vessels--the relationship between portions of coronary occlusion and collateral vessels

This study was performed to define the conditions present in chronic total occlusion of all three coronary vessels. Each left descending coronary artery (LAD), left circumflex branch (LCX) and right coronary artery (RCA) was totally occluded angiographically in 5 patients (mean age 64, male 3, female 2). Four of them had history of myocardial infarction. Anginal type was effort angina in all patients, and two cases showed unstable angina. Good collateral supply was found in the distal portions of occluded vessels from proximally located branches, such as Conus branch, Right ventricular branch, Septal branch and Left atrial circumflex branch. Almost all of the occlusions were located at mid portions (13/15: mid, 2/15: proximal). Ejection fractions (EF%) of the 5 patients were 70%, 69%, 60%, 28% and 22% respectively. EF was correlated with the degree of collateral supply and one of them (22%) ended in sudden death. These findings suggest that the mid portion occlusion, good collateral supply and a long history of angina pectoris are important factors involved in chronic total occlusion of the three coronary vessels.     

Brugada phenocopy secondary to extensive inferior wall ischemia induced by coronary steal effect

The diagnosis of Brugada syndrome is usually made with a typical ECG pattern. However, different disorders can emulate this pattern (Brugada phenocopies). Pathophysiologic mechanisms underlying this phenomenon remain controversial. We describe the development of type‐1 Brugada ECG pattern associated with extensive coronary steal effect during myocardial perfusion scintigraphy. Proximal occlusion of the right coronary artery and severe proximal stenosis in distally occluded left circumflex artery were confirmed by coronary angiogram. Brugada ECG pattern can be a reversible sign associated with inferior left ventricular and right ventricular ischemia. Its presence during acute ischemia deserves appropriate risk stratification.     

Recurrence of Prinzmetal angina seven years following aortocoronary bypass surgery: a clinical and angiographic follow-up.

A patient with Prinzmetal angina and ST segment elevation in the anterior ECG leads became asymptomatic after a 50% left anterior descending coronary artery stenosis was bypassed. However, seven years later Prinzmetal angina recurred but with ST segment elevation in the inferior ECG leads. Although the coronary bypass graft had remained patent, the proximal and distal left anterior descending coronary artery was occluded. No significant stenosis was present in the right coronary artery. Perhexiline maleate controlled his symptoms but when the drug was stopped because of side effects an acute inferior myocardial infarction occurred.