Right heart catheterization and cardiac complications in patients undergoing noncardiac surgery: an observational study

CONTEXT: Right heart catheterization (RHC) is commonly performed before high-risk noncardiac surgery, but the benefit of this strategy remains unproven. OBJECTIVE: To evaluate the relationship between use of perioperative RHC and postoperative cardiac complication rates in patients undergoing major noncardiac surgery. DESIGN: Prospective, observational cohort study. SETTING: Tertiary care teaching hospital in the United States. PATIENTS: Patients (n = 4059 aged >/=50 years) who underwent major elective noncardiac procedures with an expected length of stay of 2 or more days between July 18, 1989, and February 28, 1994. Two hundred twenty one patients had RHC and 3838 did not. MAIN OUTCOME MEASURE: Combined end point of major postoperative cardiac events, including myocardial infarction, unstable angina, cardiogenic pulmonary edema, ventricular fibrillation, documented ventricular tachycardia or primary cardiac arrest, and sustained complete heart block, classified by a reviewer blinded to preoperative data. RESULTS: Major cardiac events occurred in 171 patients (4.2%). Patients who underwent perioperative RHC had a 3-fold increase in incidence of major postoperative cardiac events (34 [15.4%] vs 137 [3.6%]; P<.001). In multivariate analyses, the adjusted odds ratios (ORs) for postoperative major cardiac and noncardiac events in patients undergoing RHC were 2.0 (95% confidence interval [CI], 1.3-3.2) and 2.1 (95% CI, 1.2-3.5), respectively. In a case-control analysis of a subset of 215 matched pairs of patients who did and did not undergo RHC, adjusted for propensity of RHC and type of procedure, patients who underwent perioperative RHC also had increased risk of postoperative congestive heart failure (OR, 2.9; 95% CI, 1.4-6.2) and major noncardiac events (OR, 2.2; 95% CI, 1.4-4.9). CONCLUSIONS: No evidence was found of reduction in complication rates associated with use of perioperative RHC in this population. Because of the morbidity and the high costs associated with RHC, the impact of this intervention in perioperative care should be evaluated in randomized trials.     

Long-term cardiac prognosis following noncardiac surgery. The Study of Perioperative Ischemia Research Group.

OBJECTIVE--To determine the long-term (2-year) cardiac prognosis of high-risk patients undergoing noncardiac surgery and to determine the predictors of long-term adverse cardiac outcome. DESIGN--Prospective cohort study. Historical, clinical, and laboratory data were collected during the in-hospital period, and at 6 months, 1 year, and 2 years following surgery. Data were analyzed using proportional hazards models. SETTING--University-affiliated Veterans Affairs medical center. POPULATION--A consecutive sample of 444 patients with or at high risk for coronary artery disease who had undergone elective noncardiac surgery and were discharged from the hospital in stable condition. MAIN OUTCOME MEASURES--Cardiac death, myocardial infarction, unstable angina, progressive angina requiring coronary artery bypass graft surgery or coronary angioplasty, and new unstable angina requiring hospitalization. RESULTS--Forty-seven patients (11%) had major cardiovascular complications during a 728-day (median) follow-up period: 24 had cardiac death; 11, nonfatal myocardial infarction; six, progressive angina requiring coronary artery bypass graft surgery or coronary angioplasty; and six, new unstable angina requiring hospitalization. Thirty percent of outcomes occurred within 6 months of surgery and 64% within 1 year. Five independent predictors of long-term outcome were identified. Three predictors reflected the preexisting chronic disease state: (1) the presence of known vascular disease (hazard ratio, 6.1; 95% confidence interval [CI], 2.5 to 15.0; P less than .0001); (2) a history of congestive heart failure (hazard ratio, 5.0; 95% CI, 2.0 to 12.0; P less than .0005); and (3) known coronary artery disease (hazard ratio, 3.7; 95% CI, 1.7 to 8.0; P less than .0007). Two predictors reflected acute postoperative ischemic events: (1) myocardial infarction/unstable angina (hazard ratio, 20; 95% CI, 7.5 to 53.0; P less than .0001) and (2) myocardial ischemia (hazard ratio, 2.2; 95% CI, 1.1 to 4.3; P less than .03). Patients surviving a postoperative in-hospital myocardial infarction had a 28-fold increase in the rate of subsequent cardiac complications within 6 months following surgery, a 15-fold increase within 1 year, and a 14-fold increase within 2 years (95% CI, 5.8 to 32; P less than .00001). Seventy percent of all long-term adverse outcomes were preceded by in-hospital postoperative ischemia that occurred at least 30 days (median, 282 days) before the long-term event. The development of congestive heart failure or ventricular tachycardia (without ischemia) during hospitalization was not associated with adverse long-term outcome. CONCLUSIONS--The incidence of long-term adverse cardiac outcomes following noncardiac surgery is substantial. At increased risk are patients with chronic cardiovascular disease; at highest risk are patients with acute perioperative ischemic events. We conclude that survivors of in-hospital perioperative ischemic events, specifically myocardial infarction, unstable angina, and postoperative ischemia, warrant more aggressive long-term follow-up and treatment than is currently practiced.     

Monitoring for myocardial ischemia during noncardiac surgery. A technology assessment of transesophageal echocardiography and 12-lead electrocardiography. The Study of Perioperative Ischemia Research Group.

OBJECTIVE--Transesophageal echocardiography (TEE) and 12-lead electrocardiography (ECG) are sophisticated techniques that are increasingly being used to monitor for myocardial ischemia during noncardiac surgery. We examined whether the routine use of these techniques has incremental clinical value in identifying patients at high risk for perioperative ischemic outcomes when compared with preoperative clinical data and intraoperative monitoring using continuous two-lead bipolar ECG. DESIGN--Cohort study. SETTING--Veterans Affairs medical center. PATIENTS--A total of 332 men undergoing noncardiac surgery who had or were at high risk for coronary artery disease. INTERVENTIONS--TEE, 12-lead ECG, and two-lead ECG were performed continuously during noncardiac surgery (47% vascular, 53% nonvascular). Monitoring results were not available to anesthesiologists or surgeons, and data were blindly analyzed after surgery. MAIN OUTCOME MEASURE--Perioperative ischemic outcomes (cardiac death, nonfatal myocardial infarction, unstable angina). RESULTS--In a subset of 285 patients who were adequately studied by all three techniques, 111 patients (39%) were identified as having intraoperative myocardial ischemia (by one or more monitoring techniques). By univariate analysis, intraoperative ischemia was associated with all perioperative cardiac outcomes, including ischemic outcomes, congestive heart failure, and ventricular tachycardia (P less than or equal to .02 for each of the three monitoring techniques). However, when monitoring results for TEE and 12-lead ECG were added to a multivariate model that included preoperative clinical data and continuous two-lead ECG results, the incremental value of TEE was small (odds ratio, 2.6; 95% confidence interval [CI], 1.2 to 5.7; P = .02) and that of 12-lead ECG was not significant (odds ratio, 1.5; 95% CI, 0.6 to 3.8). Furthermore, when the multivariate analysis was repeated with only ischemic outcomes, neither TEE nor 12-lead ECG retained significant associations (odds ratio, 2.2; 95% CI, 0.5 to 9.4, and odds ratio, 1.1; 95% CI, 0.2 to 6.1, respectively). CONCLUSION--When compared with preoperative clinical data and intraoperative monitoring using two-lead ECG, routine monitoring for myocardial ischemia with TEE or 12-lead ECG during noncardiac surgery has little incremental clinical value in identifying patients at high risk for perioperative ischemic outcomes.     

Impact of potentially lethal ventricular arrhythmias on long-term outcome in patients with chronic heart failure

Background  Potentially lethal ventricular arrhythmias (PLVAs) occur frequently in survivors after acute myocardial infarction and are increasingly recognized in other forms of structural heart diseases. This study investigated the prevalence and prognostic significance of PLVAs in patients with chronic heart failure (CHF).

Methods  Data concerning demographics, etiology of heart failure, NYHA functional class, biochemical variables, electrocardiographic and echocardiographic findings, and medical treatments were collected by reviewing hospital medical records from 1080 patients with NYHA II–IV and a left ventricular (LV) ejection fraction ≤45%. PLVAs were defined as multi-focal ventricular ectopy (>30 beats/h on Holter monitoring), bursts of ventricular premature beats, and nonsustained ventricular tachycardia. All-cause mortality, sudden death, and rehospitalization due to worsening heart failure, or cardiac transplantation during 5-year follow-up after discharge were recorded.

Results  The occurrence rate of PLVAs in CHF was 30.2%, and increased with age; 23.4% in patients <45 years old, 27.8% in those between 45–65 years old, and 33.5% in patients >65 years old (P=0.033). Patients with PLVAs had larger LV size and lower ejection fraction (both P <0.01) and higher all-cause mortality (P=0.014) during 5-year follow-up than those without PLVAs. Age (OR 1.041, 95% CI 1.004–1.079, P=0.03) and LV end-diastolic dimension (OR 1.068, 95% CI 1.013–1.126, P=0.015) independently predicted the occurrence of PLVAs. And PLVA was an independent factor for all-cause mortality (RR 1.702, 95% CI 1.017–2.848, P=0.031) and sudden death (RR 1.937, 95% CI 1.068–3.516, P=0.030) in patients with CHF.

Conclusion  PLVAs are common and exert a negative impact on long-term clinical outcome in patients with CHF.

     

In-hospital and long-term mortality in male veterans following noncardiac surgery. The Study of Perioperative Ischemia Research Group.

OBJECTIVES--To determine the causes of and risk factors for mortality following noncardiac surgery. DESIGN--Prospective cohort study. SETTING--A university-affiliated Veterans Affairs medical center. PATIENTS--Consecutive series of 474 men between the ages of 38 and 89 years (mean age, 68 years) who were undergoing major noncardiac surgery involving general anesthesia. All subjects had known coronary artery disease or were at high risk for coronary artery disease. MEASUREMENTS AND RESULTS--During the initial hospitalization, 26 patients (5%) died, most commonly from sepsis (n = 6) or cardiac diseases (n = 6). Deaths occurred from postoperative days 2 to 69; half occurred more than 3 weeks after surgery. Multivariable analysis disclosed that a history of hypertension (odds ratio [OR] = 3.8; 95% confidence interval [CI], 1.1 to 13), a severely limited activity level (OR = 9.7; 95% CI, 2.5 to 37), and a creatinine clearance of less than 0.83 mL/s (OR = 6.8; 95% CI, 2.8 to 16) were all independently associated with an increased risk of postoperative mortality. The mortality rate in patients with two or more of these risk factors was 20%, nearly eight times higher (95% CI, 3.6 to 16) than those with one or no risk factors. An additional 82 patients died within the next 2 years; cancer, renal dysfunction, congestive heart failure, and obstructive pulmonary disease were independently associated with long-term mortality. CONCLUSIONS--Even in patients at high risk of cardiac complications following surgery, noncardiac causes of death are more common. Patients with a history of hypertension, severely limited activity, and reduced renal function appear to be at especially high risk of in-hospital mortality after noncardiac surgery.     

Fatal ventricular tachycardia in association with propafenone, a new class IC antiarrhythmic agent.

A man with a past history of malignant ventricular arrhythmias occurring late after myocardial infarction was admitted for assessment. Monitoring revealed frequent ventricular premature beats and occasional non-sustained runs of ventricular tachycardia. Other drugs having failed, he was started on oral propafenone which is a new Vaughan Williams class IC antiarrhythmic agent. Several hours after starting this drug he had incessant ventricular tachycardia and subsequently died. Other class IC agents have been shown to have a high incidence of proarrhythmic effects, and particular care should be taken with these potent new drugs.     

39例急性百草枯中毒心律失常分析

  目的 探讨急性百草枯中毒时心律失常发生类型及不同类型与死亡率的关系。方法 分析39例急性百草枯中毒患者的入院心律失常心电图,其中男15例,女24例,年龄20-~49岁。结果 25例次发生窦性心动过速;22例次室性早搏（7例室性早搏二、三联律）,3例次室性心动过速（其中1例转为室性扑动及心室颤动）和1例心室停博;8例次ST-T异常及T波、U波改变。发生室性心律失常的中毒患者死亡率高于其它类型心律失常患者发生室性心律失常的中毒患者死亡率高于其他类型心律失常患者。结论 急性百草枯中毒可出现多种心律失常,发生室性心律失常患者伴有较差预后。     

原发性高血压患者血压晨峰与心律失常及心肌缺血的关系

目的 探讨原发性高血压患者血压晨峰对心脏重构以及心血管事件的影响。方法2006年2月至2009年1月在本院就诊的高血压病患者中,按就诊顺序连续入选386例高血压患者,根据动态血压检测结果,分为晨峰组（146例）和非晨峰组（240例）,均同步记录24h动态血压和动态心电图,观察24h动态血压参数,24h动态心电图检出的房性、室性心律失常及ST段偏移;行超声心动图检测左室质量指数（LVMI）、左房内径等指标。结果晨峰组与非晨峰组LVMI分别为（119±21）g／m^2和（93±12）g／m^2（P〈0．01）;左房内径分别为（46±11）mm与（38±10）mm（P〈0．05）;房性早搏检出率分别为98．6％与84．2％（P〈0．05）;房性心动过速检出率分别为54．1％与20．8％（P〈0．01）;心房颤动检出率分别为24．0％与0（P〈0．01）;室性早搏和室性心动过速的检出率分别为79．5％与57．9％（P〈0．05）和6．8％与2．5％（P〈0．05）;检出ST段水平型压低率分别为33．6％与13．8％（P〈0．01）。两组左室肥厚的检出率分别为67．1％与30．4％（P〈0．01）。53．2％的心律失常和57．6％的ST段压低发作出现在清晨6：00～8：00。相关分析表明,清晨血压和血压晨峰升高与对应时域ST段压低呈正相关。结论与无血压晨峰的高血压病患者相比,具有血压晨峰的高血压患者左心室肥厚更显著,心律失常和心肌缺血更常见,且多出现在清晨。     

Arrhythmias in dilated cardiomyopathy

Sixty-five patients with dilated cardiomyopathy underwent 24 hour electrocardiographic monitoring: 62 (95.4%) showed ventricular arrhythmias and 52 (80%) complex ventricular arrhythmias (multiform ventricular extrasystoles, paired ventricular extrasystoles and ventricular tachycardia). Complex ventricular arrhythmias correlated significantly with some haemodynamic indices of ventricular dysfunction: patients with multiform and paired ventricular extrasystoles and with ventricular tachycardia had lower values of ejection fraction (31.9 +/- 11.8%, P = 0.002) and of cardiac index (2.9 +/- 0.7 litres/min/m2, P = 0.029) than the others (41.1 11.1% and 3.5 +/- 0.9 litres/min/m2 respectively). Patients were followed for a period of 30 +/- 18 months (20 days to 64 months). During follow-up 19 died and mortality was higher among patients with multiform and paired ventricular extrasystoles and/or ventricular tachycardia. Complex ventricular arrhythmias are frequent in dilated cardiomyopathy: ventricular tachycardia and multiform and paired ventricular extrasystoles seem to be related to a more depressed ventricular function and to a poor prognosis. The importance of antiarrhythmic treatment in these patients has still to be evaluated.     

牵张激活性离子通道对膨胀大鼠心室电生理的影响

目的 制备离体心脏灌流模型,观察急性牵张左室对离体心脏电生理的作用,揭示牵张激活性离子通道在心脏机械电反馈中的作用.方法 45只大鼠分为3组:不牵张组、牵张组及牵张加链霉素组,每组15只.离体灌流大鼠心脏的同时,将一自制乳胶球囊经左心耳置入左心室.急性膨胀球囊牵张左室,记录并分析实验各组心律失常的出现频率和种类.结果 牵张组可出现室性早搏、室性心动过速等心律失常;而牵张加链霉素组仅出现室性早搏,且两组心律失常的发生率有明显差异.结论 链霉素作为牵张激活性离子通道阻断剂,能明显减少急性膨胀心室所致心律失常的发生,提示牵张激活性离子通道在急性膨胀心室致心律失常的发生中发挥重要作用.     

心脏钝性损伤的心电图改变

目的探讨心电图改变在心脏钝性损伤中的诊断意义、发生机理及其对预后的价值。方法用心脏彩超、心肌酶（ＣＰＫ－ＭＢ）、心脏核素扫描和磁共振诊断为心脏钝性损伤的９３例患者进行连续心电监护和１８导联心电图检查，７～１４ｄ内，每天复查一次心电图。结果９３例患者中发现心电图异常者７６例（８１．７２％），其中以ＳＴ－Ｔ波改变、室早、房早、室上速最常见，而且致命性心律失常占有相当比例。其中心电图改变与心脏损伤程度、心衰和预后都有明显关系。结论心脏钝性损伤所出现的多种心电图改变中以ＳＴ段抬高和新Ｑ波最具诊断价值，心电图改变可作为心脏钝性损伤患者预后的一项参考。     

Tachycardia-induced elevations in cardiac troponin in the absence of coronary artery disease

Elevations in serum cardiac troponins are used to diagnose myocardial infarction caused by ischemic heart disease. Several other conditions result in elevated cardiac makers in the absence of significant coronary artery disease. While not commonly recognized elevations of troponin I (TNI) may be seen in patients with protracted arrhythmias. We describe three patients with prolonged tachycardia, heart rates of 200-260 beats per minute, who had elevated TNI (0.81-4.6 ng/ml) but no significant coronary artery disease. Two patients presented with ventricular tachycardia and one had an atrioventricular re-entrant tachycardia. None of the patients presented with symptomatic hypotension. Coronary angiography in all three patients did not demonstrate significant coronary artery disease. The finding of an elevated TNI level may be the result of tachycardia and not myocardial infarction related to ischemic heart disease.     

Ventricular arrhythmias.

Sudden cardiac death claims thousands of Canadians annually. Ventricular tachycardia and fibrillation account for up to 85% of these deaths. Identifying the patients at risk remains a major challenge. Those who have recurrent ventricular tachycardia or have been resuscitated from ventricular fibrillation are generally considered to be at highest risk. Although ventricular premature beats in the absence of previous ventricular tachycardia or fibrillation are not helpful in identifying such patients in most cases, they can indicate increased risk for sudden cardiac death in the presence of a structural cardiac abnormality, particularly recent myocardial infarction; however, the need for treatment in such cases is speculative and is being investigated. Treatment is mandatory for survivors of an episode of ventricular fibrillation and those with recurrent sustained ventricular tachycardia or torsade de pointes ventricular tachycardia. The approach to management is either invasive or noninvasive. Selection of an antiarrhythmic agent is facilitated by knowledge of some basic electrophysiologic features of the heart and of the classification of antiarrhythmic drugs. However, drug therapy has to be individualized on the basis of efficacy, left ventricular function and adverse effects or potential adverse effects of the drug. Amiodarone therapy or nonpharmacologic therapy should be considered if a suitable antiarrhythmic agent cannot be found.     

Survey of physician practices in managing patients with chronic ventricular arrhythmias

To better understand how physicians manage patients with chronic ventricular arrhythmias, questionnaires were mailed in July, 1989, to 680 internists, family physicians and cardiologists in West Virginia. Responses were returned by 35 per cent; those from 33 physicians who seldom prescribed drugs to treat arrhythmias were excluded from analysis. Quinidine and procainamide were the preferred first-line antiarrhythmics for 53.3 per cent and 24.3 per cent of physicians, respectively. Control of symptoms was listed as the usual indication for therapy by 32.2 per cent, and improvement in prognosis by 20.1 per cent. Physicians perceived a high prognostic benefit to antiarrhythmic treatment in patients with sustained ventricular tachycardia or history of cardiac arrest, and a generally low prognostic benefit in those with mitral valve prolapse. Opinion was divided on the prognostic benefit in other patient groups including those with frequent ventricular premature beats following myocardial infarction. These results help quantify current physician practices in managing patients with chronic ventricular arrhythmias.     

复方罗布麻片联合胺碘酮治疗冠心病室性心律失常的系统评价和Meta分析

目的系统评价复方罗布麻片联合胺碘酮治疗冠心病室性心律失常的有效性和安全性。方法计算机检索在PubMed、中国知识基础设施工程网（CNKI）、中国生物医学文献数据库（CBM）、维普（VIP）和万方（WanFang）数据库收录的有关复方罗布麻片联合胺碘酮治疗冠心病室性心律失常的疗效对比文献。采用Cochrane Handbook 5.1.0评价随机对照试验的质量标准,对纳入文献进行质量评价,判断偏倚风险。应用RevMan5.3软件进行统计学分析。结果最终纳入9项研究,合计1 033例病人,其中治疗组464例,对照组569例（胺碘酮组464例,普罗帕酮组105例）。Meta分析结果:复方罗布麻片联合胺碘酮治疗心律失常的临床总有效率高于单用胺碘酮（OR=5.46;95%CI:3.40~8.75;Z=7.04;P < 0.00001;I2=0%）、普罗帕酮（OR=2.99;95%CI:1.48~6.07;Z=3.04;P=0.002;I2=0%）;室早发生次数（SMD=-1.39;95%CI:-1.61~-1.17;Z=12.34;P < 0.00001;I2=0%）和短阵室速发生次数（SMD=-1.51;95%CI:-1.73~-1.28;Z=13.16;P < 0.00001;I2=0%）比单用胺碘酮均明显减少;治疗后不良反应发生率比较,2组差异无统计学意义（OR=0.94;95%CI:0.58~1.53;Z=0.25;P=0.80;I2=0%）。结论复方罗布麻片联合胺碘酮治疗冠心病室性心律失常的效果优于单独使用胺碘酮、普罗帕酮,并且应用安全。     

Preoperative beta-blocker use and mortality and morbidity following CABG surgery in North America

CONTEXT: beta-Blockade therapy has recently been shown to convey a survival benefit in preoperative noncardiac vascular surgical settings. The effect of preoperative beta-blocker therapy on coronary artery bypass graft surgery (CABG) outcomes has not been assessed. OBJECTIVES: To examine patterns of use of preoperative beta-blockers in patients undergoing isolated CABG and to determine whether use of beta-blockers is associated with lower operative mortality and morbidity. DESIGN, SETTING, AND PATIENTS: Observational study using the Society of Thoracic Surgeons National Adult Cardiac Surgery Database (NCD) to assess beta-blocker use and outcomes among 629 877 patients undergoing isolated CABG between 1996 and 1999 at 497 US and Canadian sites. MAIN OUTCOME MEASURE: Influence of beta-blockers on operative mortality, examined using both direct risk adjustment and a matched-pairs analysis based on propensity for preoperative beta-blocker therapy. RESULTS: From 1996 to 1999, overall use of preoperative beta-blockers increased from 50% to 60% in the NCD (P<.001 for time trend). Major predictors of use included recent myocardial infarction; hypertension; worse angina; younger age; better left ventricular systolic function; and absence of congestive heart failure, chronic lung disease, and diabetes. Patients who received beta-blockers had lower mortality than those who did not (unadjusted 30-day mortality, 2.8% vs 3.4%; odds ratio [OR], 0.80; 95% confidence interval [CI], 0.78-0.82). Preoperative beta-blocker use remained associated with slightly lower mortality after adjusting for patient risk and center effects using both risk adjustment (OR, 0.94; 95% CI, 0.91-0.97) and treatment propensity matching (OR, 0.97; 95% CI, 0.93-1.00). Procedural complications also tended to be lower among treated patients. This treatment advantage was seen among the majority of patient subgroups, including women; elderly persons; and those with chronic lung disease, diabetes, or moderately depressed ventricular function. Among patients with a left ventricular ejection fraction of less than 30%, however, preoperative beta-blocker therapy was associated with a trend toward a higher mortality rate (OR, 1.13; 95% CI, 0.96-1.33; P =.23). CONCLUSIONS: In this large North American observational analysis, preoperative beta-blocker therapy was associated with a small but consistent survival benefit for patients undergoing CABG, except among patients with a left ventricular ejection fraction of less than 30%. This analysis further suggests that preoperative beta-blocker therapy may be a useful process measure for CABG quality improvement assessment.     

Detection and significance of intraoperative and postoperative myocardial ischemia in peripheral vascular surgery.

OBJECTIVE--To determine the incidence and significance of intraoperative and postoperative myocardial ischemia and their relationship to preoperative ischemia and postoperative cardiac events in patients undergoing peripheral arterial surgery. DESIGN--Prospective cohort trial. PATIENTS--One hundred fifteen patients undergoing elective vascular surgery who met predefined eligibility criteria and were thought to have acceptable cardiac risk as assessed by independent cardiologists. INTERVENTIONS--Ambulatory electrocardiographic monitoring preoperatively, intraoperatively, and up to 72 hours postoperatively. MEASUREMENTS--Preoperative clinical characteristics and laboratory data were collected. Predefined adverse cardiac events were identified by an investigator who was "blinded" to monitoring results. Monitor recordings were interpreted for ST-segment depression by investigators blinded to patient information. MAIN RESULTS--Intraoperative ischemia was present in 21 patients (18%), and postoperative ischemia was present in 35 (30%). There were 16 postoperative cardiac events. The relative risk of suffering a cardiac event was 2.7 in patients with intraoperative ischemia and was 16 in patients with postoperative ischemia. Preoperative ischemia closely correlated with intraoperative and postoperative ischemia. Preoperative and postoperative ischemia preceded cardiac events in 14 of 16 patients. CONCLUSIONS--Preoperative ischemia appears to identify high-risk patients, and subsequent perioperative monitoring detects silent ischemia that commonly precedes clinical events and that may be treatable with anti-ischemia therapy.     

Perioperative anesthetic risk of noncardiac surgery in hypertrophic obstructive cardiomyopathy

To determine their perioperative risk, we reviewed the records of 35 patients with hypertrophic cardiomyopathy diagnosed by cardiac ultrasound and/or catheterization who underwent general (52) or spinal (four) anesthesia--a total of 56 major surgical procedures. There were no operative or related perioperative deaths and no significant ventricular tachyarrhythmias. Intraoperative or postoperative complications included: myocardial infarction with heart failure in one patient who also had coronary artery disease and was one of three patients who had spinal anesthesia, arrhythmia requiring therapy in eight, and angina during supraventricular tachycardia in one. We conclude that the risk of general anesthesia and major noncardiac surgery is low in patients with hypertrophic obstructive cardiomyopathy. Spinal anesthesia, which decreases systemic vascular resistance and increases capacitance, may be relatively contraindicated. Concomitant coronary artery disease may increase the risk.     

The prevalence and outcome of ventricular arrhythmias in acute myocardial infarction

One hundred and seventy-two consecutive cases of acute myocardial infarction (MI) admitted to a coronary care unit were studied with regard to ventricular arrhythmias - pre-mature ventricular contractions (PVC), ventricular tachycardia (VT) and ventricular fibrillation (VF). Sixty-seven (39%) patients had ventricular arrhythmias (PCC-VT-VF), of whom 17 (9.8%) had VT and 11 (6.4%) VF. VT and VF, but not total arrhythmias, were more common in anterior infarctions. Fifty-six out of 67 (83.5%) of these patients arrived at Accident & Emergency (A&E) within the first six hours of onset of chest pain. Ten out of 11 (91 %) patients who had VF did so in the first six hours. PVCs were poor predictors of the occurrence of VF (positive predictive value 5.9%). Forty-three patients (84%) who had PVCs did not develop any further arrhythmias. Spontaneous heart rate had no influence on the occurrence of ventricular arrhythmias. Frequent PVCs were more commonly associated with progression to VT and VF. In 30 cases (88%) lignocaine was effective. There was no death due to VT/VF and all responded to drugs and/or cardioversion.     

Life-threatening ventricular tachycardia and fibrillation induced by painless myocardial ischemia during exercise testing

The clinical importance of myocardial ischemia without associated symptoms in patients with atherosclerotic coronary disease has not been clarified. We present three patients in whom painless cardiac ischemia was associated with the induction of cardiac arrest and/or ventricular tachycardia/fibrillation. In the two surviving patients, programmed ventricular stimulation did not induce ventricular arrhythmias. In one patient, successful coronary bypass surgery resulted in the elimination of exercise-induced painless myocardial ischemia and associated ventricular fibrillation; the other patient suffered a myocardial infarction after which ischemia and ventricular tachyarrhythmias could not be reproduced with exercise testing. We conclude that painless myocardial ischemia can cause life-threatening arrhythmias and is, therefore, a potentially lethal phenomenon.