Early ventricular fibrillation in patients with acute myocardial infarction: correlation with coronary angiographic findings

To define coronary angiographic characteristics of patientsexperiencing early primary ventricular fibrillation (VF) inthe acute phase of myocardial infarction we studied 266 consecutivepatients without clinical evidence of heart failure. Twenty-sixpatients (group 1) experienced early (< 12 h from the onsetof symptoms of myocardial infarction) primary VF whereas 240patients (group 2) with the same clinical characteristics servedas an appropriately matched cohort. All patients were catheterizedbefore or soon after hospital discharge (1 to 8 weeks afterthe acute event). There was no significant difference in left ventricular ejectionfraction between the two groups of patients (39.6±6%vs 36.9±8%, P = ns). Patients with early VF had a significantlygreater number of diseased vessels than those without VF (3.38±1.05vs 2.03±1.25. P <0.001) and a higher coronary arteriographicGensini score (29.31±4.80 vs 20.16±4.14, P <0.001).The left anterior descending coronary artery was identifiedas the infarct-related vessel in 53.6% of group 1 vs 44.5% ofgroup 2 patients (P <0.05). The mean maximal serum creatinekinase values were not significantly different (1897±1062vs 1426 ±839 IU.l–1, P=ns) between the two groups. These data indicate that patients with early primary VF in thesetting of acute myocardial infarction may have more extensivecoronary artery disease than similar patients without VF. Aworse prognosis could be anticipated for these patients on thebasis of worse coronary anatomy. A more aggressive therapeuticapproach with routine coronary angiography before hospital dischargecould reasonably be justified for patients with early primaryVF complicating acute myocardial infarction.     

Primary ventricular fibrillation in acute myocardial infarction

Primary ventricular fibrillation is an acute life-threatening event if not treated promptly. The ability to predict this event during the course of an acute myocardial infarction could therefore have an important impact on the mode of treatment and monitoring. In the present study, clinical and laboratory information available at the initial evaluation of patients with an acute myocardial infarction was tested for its ability to predict subsequent primary ventricular fibrillation. Multiple logistic regression analysis was employed to select the predictors. Serum potassium, serum creatinine and no smoking were significant predictors of subsequent ventricular fibrillation. Although the prediction was statistically significant, the clinical value of the prediction is quite limited.     

Routine coronary angiographic follow-up and subsequent revascularization in patients with acute myocardial infarction

The aims of the present study are to: (1) clarify the angiographic follow-up (AFU) rate after discharge; (2) elucidate the characteristics of those undergoing it; and (3) determine the impact of AFU on subsequent revascularization procedures among patients with acute myocardial infarction (AMI). Three thousand and twenty-one consecutive patients presenting within 48 h of AMI onset were enrolled from 17 centers in Japan between January 1999 and June 2001. To clarify the frequency of AFU and their characteristics, 2736 patients who survived at discharge were analyzed. Among 1160 patients matched by propensity score, the impact of AFU on subsequent revascularization was analyzed. Of 2736 patients, 1367 (50%) underwent AFU and constituted the lower-risk population. Of the 580 matched patient pairs, 120 (21%) in the clinical follow-up group and 198 (34%) in the AFU group underwent subsequent revascularization (hazard ratio 7.54; 95% confidence interval 5.74–9.91). Of the 198 patients in the AFU group, 157 (79%) underwent revascularization at the discretion of the responsible physician based on angiographic findings. Angiographic follow-up led to more subsequent revascularization. More evidence would be necessary to determine the effectiveness and the methods by which patients are selected.     

Observations on patients with primary ventricular fibrillation complicating acute myocardial infarction.

In order to evaluate the events preceding primary ventricular fibrillation (PVF), continuous tape recording was performed in 262 patients consecutively admitted to the hospital within six hours of infarction in whom antiarrhythmic therapy was withheld. Warning arrhythmias (defined as ventricular ectopic beats occurring with a frequency of more than five beats per minute, in runs, falling in the vulnerable phase of the cardiac cycle or being multiformed) were registered in an equal percentage in patients who did or did not develop PVF. Immediately prior to PVF seven patients showed sinus tachycardia, 10 a sinus rate ranging from 60 to 100 beats per minute and two bradycardia due to complete atrioventricular block. The ventricular ectopic beat initiating PVF had a late coupling interval (QR'/QT larger than or equal to 0.85) in 11 patients and a left bundle branch block configuration as frequent as a right bundle branch block. Conclusions: 1) Warning arrhythmias are not considered good criteria for institution of antiarrhythmic therapy in order to prevent PVF. 2) In patients with sinus rhythm there may be an association between heart rate and onset of PVF. 3) The malignancy of a ventricular ectopic beat is not determined by its coupling interval or its configuration.     

Primary ventricular fibrillation complicating acute myocardial infarction

A controversy exists about whether or not primary ventricular fibrillation in patients with acute myocardial infarction is always preceded by premonitory cardiac arrhythmias. The monitoring system in the Toronto General Hospital Coronary Unit yields a permanent record of every heartbeat and provides a unique opportunity to answer this question. Of 851 patients with proved myocardial infarction, primary ventricular fibrillation developed in 20; 12 of these had frequent ventricular arrhythmias before ventricular fibrillation. In 5 patients, ventricular fibrillation occurred without any warning arrhythmia and the remaining 3 patients had only rare ventricular premature beats.     

Predicting angiographic distal embolization following percutaneous coronary intervention in patients with acute myocardial infarction

The aim of this study was to investigate the relation between lesion morphology identified by intravascular ultrasound (IVUS) before intervention and angiographic distal embolization after percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI). PCI for AMI has already been established as beneficial therapy, although some complications remain unresolved. Distal embolization is 1 of the important complications of PCI. Recently, some new devices have been developed for the prevention of distal embolization. However, few studies exist that look into the relation between lesion morphology and distal embolization. IVUS was performed safely in 140 consecutive patients with AMI before coronary intervention. No patient received thrombolytic therapy. From the incidence of angiographic distal embolization, patients were divided into 2 groups--an embolization group and a nonembolization group--and clinical background, IVUS, and angiographic information were evaluated. Distal embolization was observed in 12 patients (9%). Peak creatine kinase levels (3,877 +/- 2,285 vs 2,293 +/- 1,792 IU/L, p <0.05) and the incidence of angiographic thrombus (25% vs 5%, p <0.05) and intracoronary mobile mass detected by IVUS (75% vs 16%, p <0.001) were higher for patients in the embolization group. From the multivariate logistic regression analysis, only an intracoronary mobile mass detected by IVUS emerged as a predictor of distal embolization (odds ratio 53, 95% confidence interval 2.7 to 1,040, p <0.01). Patients with an intracoronary mobile mass detected by IVUS are prone to distal embolization after PCI and larger infarction. IVUS imaging before PCI may be useful for determining which patients need a distal protection device.     

Hypokalaemia and ventricular fibrillation in acute myocardial infarction

Serum potassium concentrations obtained on admission to hospital were inversely related to the incidence of ventricular fibrillation in 289 women and 785 men with acute myocardial infarction, 92 of whom developed ventricular fibrillation. Hypokalaemia (serum potassium concentration less than or equal to 3.5 mmol/l) was found in 122 patients (11.4%). The incidence of ventricular fibrillation was significantly greater in patients with hypokalaemia compared with those classified as normokalaemic (serum potassium concentration greater than or equal to 3.6 mmol/l) (17.2% v 7.4%). The increased risk of ventricular fibrillation in the hypokalaemic group was about the same for women and men. While they were in hospital patients with hypokalaemia developed ventricular fibrillation significantly earlier than did normokalaemic patients (median 0.3 hours v 7 hours). Hypokalaemia was more common in women (17.3%) than in men (9.2%), and 55% of the hypokalaemic patients had been treated with diuretics before admission compared with 22% of the normokalaemic group. Hypokalaemia on admission to hospital predicts an increased likelihood and early occurrence of ventricular fibrillation in patients with acute myocardial infarction.     

急性非Q波心肌梗死的冠状动脉造影特点

目的:分析急性非Q波心肌梗死(NQMI)相关血管病变的影像特点。方法:回顾性分析进行冠状动脉造影的NQMI96例,以GE血管造影机的LCPlus计算测量系统对病变血管进行QCA分析。结果:单支血管病变34例(35.4%),2支血管病变26例(27.1%),多支血管病变36例(37.5%),合并左主干病变9例。梗死相关血管为左主干2例;前降支病变50例;回旋支病变26例;右冠状动脉病变18例。其中A型病变26例(44.8%),B型病变19例(32.7%),C型病变13例(22.4%)。结论:NQMI多支血管病变、80%以上的严重狭窄发生率较高,影像学上以B型、C型病变多见。     

Initiation of ventricular fibrillation by supraventricular beats in patients with acute myocardial infarction

The role of supraventricular extrasystoles in the initiation of ventricular arrhythmia was studied in 72 consecutive patients who developed primary ventricular fibrillation during the acute phase of myocardial infarction. In six patients (8%), a total of 12 episodes of ventricular fibrillation and 16 episodes of ventricular tachycardia were initiated by supraventricular extrasystoles. Ventricular fibrillation and tachycardia were initiated by single supraventricular extrasystoles in 16 and by salvos greater than or equal to two beats in 12 episodes. The RR coupling interval of the supraventricular impulse immediately preceding ventricular tachycardia ranged from 240 to 420 ms (mean 356 (62)) and was characteristic of R-on-T (prematurity index less than 1) in 63% of episodes. Average peak serum creatine kinase activity in the six patients in whom ventricular tachycardia was initiated by a supraventricular extrasystole was 1275 units compared with 720 units in the remaining 66 patients. Five of these six patients later showed evidence of pump failure. Lignocaine or procainamide or both suppressed the ventricular arrhythmia in five of the six patients. The initiation of ventricular fibrillation or tachycardia by supraventricular extrasystoles in acute myocardial infarction is not uncommon and may reflect the increased vulnerability of the heart after a large infarct. These arrhythmias may respond to drugs that suppress ventricular irritability.     

年轻急性心肌梗死患者临床及冠状动脉病变特征分析

目的 探讨年轻急性心肌梗死（AMI）患者临床及冠状动脉病变特征.方法 从我院2005年1月至2010年9月期间收治的AMI患者中,选取年龄＜40岁有完整冠脉造影资料的AMI患者48例作为年轻组,选取同期年龄＞60岁有完整冠脉造影资料的AMI患者52例作为对照组.比较两组的临床资料及冠脉造影结果.结果 两组患者均为男性占优势,而年轻组这一优势更加显著（91.7%比57.7%,P＜0.05）.年轻组中有冠心病家族史、长期大量吸烟、肥胖、血脂异常及ST段抬高型心肌梗死（STEMI）的比例均高于对照组（分别为27.1%比 9.2%,81.3%比 40.4%,47.9%比26.9%,29.2%比19.2%,89.6%比65.4%,P均＜0.05）,而高血压、糖尿病、既往劳累性心绞痛及非ST段抬高型心肌梗死（NSTEMI）的比例均低于对照组（分别为33.3%比51.9%,16.7%比32.7%,12.5%比38.5%,10.4%比34.6%,P值均＜0.05）.年轻组TG高于对照组[（179.6±32.5）mg/dl比（138.5±27.3） mg/dl,P＜0.05],HDL-C低于对照组[（36.7±16.8）mg/dl比 （43.2±13.7）mg/dl,P＜0.05],而TC及LDL-C均与对照组相当[分别为（191.9±45.3）mg/dl比（187.4±42.8）mg/dl,P＞0.05;（118.4±30.5）mg/dl比（115.7±36.6）mg/dl,P＞0.05].年轻组中就诊时有典型胸痛的比例高于对照组（70.8%比28.8%,P＜0.05）.年轻组罪犯血管在左主干者占2.1%,前降支者占56.3%,回旋支者为8.3%,右冠状动脉者占33.3%,和对照组相比,差异无统计学意义.年轻组单支血管病变所占比例明显高于对照组（56.3%比26.9%,P＜0.05）,而多支血管病变所占比例明显低于对照组（37.3%比71.2%,P＜0.05）.结论 长期大量吸烟、冠心病家族史、肥胖、血脂异常是年轻人患AMI的主要危险因素.年轻AMI患者发病时症状典型,多表现为STEMI,且多为单支血管病变.     

Late induction of tachycardia in patients with ventricular fibrillation associated with acute myocardial infarction

A prospective study was made of 57 asymptomatic patients, 1 to 24 months after acute myocardial infarction, 17 with (Group I) and 40 without (Group II) ventricular fibrillation during the acute event. None of the 57 patients had symptomatic arrhythmias, uncontrolled heart failure or unstable angina. There was no significant difference between the two patient groups in time from acute myocardial infarction, medication used or left ventricular ejection fraction. Repetitive forms of arrhythmia (Lown grade 4) were more prevalent (29 versus 16%, not significant) during 24 hour ambulatory monitoring in patients in Group I (ventricular fibrillation group). Programmed extrastimulation was performed using 1 to 3 twice-threshold, 2 ms decremental extrastimuli delivered during right ventricular drive. Of the 17 patients in Group I, 8 had no induced arrhythmia (less than or equal to 4 extra responses), 4 had nonsustained ventricular tachycardia and 5 had sustained ventricular tachycardia (degenerating into ventricular fibrillation requiring electrical reversion in 4). None of the 40 patients in Group II had induced sustained ventricular tachycardia (p less than 0.005), although 9 had nonsustained ventricular tachycardia. Patients with ventricular fibrillation during acute myocardial infarction may have an increased risk for ventricular tachycardia or ventricular fibrillation that may be exposed by programmed electrical stimulation even when not yet clinically manifest.     

胺碘酮治疗中老年人急性心肌梗死合并快速心室率心房颤动的疗效观察

目的观察胺碘酮治疗中老年人急性心肌梗死合并快速心室率心房颤动的临床疗效。方法对2013-05~2016-05收治的60例发生心肌梗死的中老年患者,入院24 h内并发心室率120次/mim快速心室率心房颤动的中老年患者,年龄48~78岁,给予胺碘酮静脉加口服治疗,观察临床疗效。结果 60例患者中51例(85%)在48 h转复为窦性心律,4例死亡,5例未转复,疗效显著,心室率下降明显(P0.01),血压无明显变化(P0.05)。不良反应:窦性心动过缓1例,长R-R间歇3例,血压下降1例,静脉炎1例,予停药或对症处理后均好转。56例患者出院后随访30 d内无一例死亡,无其他不良反应发生。结论中老年人急性心肌梗死合并快速心室率心房颤动患者,应用胺碘酮静脉加口服治疗疗效显著、不良反应率低,值得临床推广应用。     

Out-of-hospital pleomorphic ventricular tachycardia and resuscitation: association with acute myocardial ischemia and infarction.

Pleomorphic ventricular tachycardia is characterized by QRS complexes with repeated variation in polarity, amplitude, and regularity. When associated with prolongation of the QT interval, the term torsades de pointes is used to describe the arrhythmia. It usually is seen clinically in association with class IA antiarrhythmic drugs such as quinidine and procainamide, bradycardia, hypokalemia, and, much less often, other drugs and electrolyte disorders as well as a result of congenital and neurogenic causes. It also may accompany acute myocardial infarction or ischemia. We describe four patients in whom pleomorphic ventricular tachycardia was observed as the presenting rhythm or during the course of resuscitation in out-of-hospital cardiac arrest. In all four patients, acute myocardial ischemia appeared to be the provocative mechanism. Therapeutic implications include an awareness of the unusual behavior of this arrhythmia, especially its propensity to terminate spontaneously. Such awareness may prevent the delivery of unnecessary defibrillatory shocks.     

Left ventricular aneurysm formation after anterior myocardial infarction: clinical and angiographic determinants in 809 patients.

BACKGROUND: Previous studies have reported controversial results regarding the clinical and angiographic factors involved in the left ventricular aneurysm (LVA) formation after myocardial infarction (MI). OBJECTIVE: This study was performed to determine the clinical and angiographic factors that are priori predictors of LVA following anterior myocardial infarction and so to provide a paradigm which may identify patients who were candidates for aneurysm formation. METHODS: Of the patients who underwent coronary angiography during the interval between 1995 and 2000 in our clinic, 809 were found to have anterior MI and LVA (aneurysm group) (677 men, 132 women, mean age 53.3+/-11.4 years). The clinical and the angiographic data of these patients were compared with those of 446 patients (399 men, 47 women, mean age 55.2+/-10.5 years) with previous anterior MI and without LVA (control group). RESULTS: LVA was found to occur more frequently in females (16.3% in women and 10.4%, in men, P=0.03) and in patients without previous angina (23.5 vs. 8.2%, P<0.0001). Major cardiovascular risk factors, previous anti-anginal medication and thrombolytic therapy did not show a significant difference between the two groups. Angiographic examination revealed that single-vessel disease, proximal left anterior descending artery (LAD) stenosis, total LAD occlusion, mean stenosis in LAD artery, end-diastolic pressure and left ventricular score were all higher in the aneurysm group compared to control group. After adjustment for other clinical and angiographic variables, single-vessel disease [odds ratio (OR) 5.89, 95% confidence interval (CI)=3.68-9.28, P<0.0001), absence of previous angina (OR=4.21, 95% CI=2.1-7.48, P=0.0003), total LAD occlusion (OR=2.63, 95% CI=1.97-3.53, P<0.0017) and female gender (OR=1.60, 95% CI=1.20-2.28, P=0.043) remained the independent determinants of LVA formation after anterior MI. CONCLUSION: In patients with LVA, logistic regression analysis revealed that (1) single-vessel disease, (2) absence of previous angina, (3) total LAD occlusion and (4) female gender were independent determinants in the formation of LVA after anterior MI. Coronary collateral status and risk factors, such as hypertension, diabetes mellitus, hypercholesterolemia, smoking and family history of CAD were not found to be important determinants in the aneurysm formation.     

Initiation of ventricular fibrillation by supraventricular beats in patients with acute myocardial infarction.

The role of supraventricular extrasystoles in the initiation of ventricular arrhythmia was studied in 72 consecutive patients who developed primary ventricular fibrillation during the acute phase of myocardial infarction. In six patients (8%), a total of 12 episodes of ventricular fibrillation and 16 episodes of ventricular tachycardia were initiated by supraventricular extrasystoles. Ventricular fibrillation and tachycardia were initiated by single supraventricular extrasystoles in 16 and by salvos greater than or equal to two beats in 12 episodes. The RR coupling interval of the supraventricular impulse immediately preceding ventricular tachycardia ranged from 240 to 420 ms (mean 356 (62)) and was characteristic of R-on-T (prematurity index less than 1) in 63% of episodes. Average peak serum creatine kinase activity in the six patients in whom ventricular tachycardia was initiated by a supraventricular extrasystole was 1275 units compared with 720 units in the remaining 66 patients. Five of these six patients later showed evidence of pump failure. Lignocaine or procainamide or both suppressed the ventricular arrhythmia in five of the six patients. The initiation of ventricular fibrillation or tachycardia by supraventricular extrasystoles in acute myocardial infarction is not uncommon and may reflect the increased vulnerability of the heart after a large infarct. These arrhythmias may respond to drugs that suppress ventricular irritability.     

Hypokalaemia and ventricular fibrillation in acute myocardial infarction.

Serum potassium concentrations obtained on admission to hospital were inversely related to the incidence of ventricular fibrillation in 289 women and 785 men with acute myocardial infarction, 92 of whom developed ventricular fibrillation. Hypokalaemia (serum potassium concentration less than or equal to 3.5 mmol/l) was found in 122 patients (11.4%). The incidence of ventricular fibrillation was significantly greater in patients with hypokalaemia compared with those classified as normokalaemic (serum potassium concentration greater than or equal to 3.6 mmol/l) (17.2% v 7.4%). The increased risk of ventricular fibrillation in the hypokalaemic group was about the same for women and men. While they were in hospital patients with hypokalaemia developed ventricular fibrillation significantly earlier than did normokalaemic patients (median 0.3 hours v 7 hours). Hypokalaemia was more common in women (17.3%) than in men (9.2%), and 55% of the hypokalaemic patients had been treated with diuretics before admission compared with 22% of the normokalaemic group. Hypokalaemia on admission to hospital predicts an increased likelihood and early occurrence of ventricular fibrillation in patients with acute myocardial infarction.