Temporal trends (1975 through 1990) in the incidence and case-fatality rates of primary ventricular fibrillation complicating acute myocardial infarction. A communitywide perspective

Twenty-five year trends (1986-2011) in hospital incidence and case-fatality rates of ventricular tachycardia and ventricular fibrillation complicating acute myocardial infarction

BACKGROUND

Long-term trends in the incidence rates (IRs) and hospital case-fatality rates (CFRs) of ventricular tachycardia (VT) and ventricular fibrillation (VF) among patients hospitalized with acute myocardial infarction (AMI) have not been recently examined.

METHODS

We used data from 11,825 patients hospitalized with AMI at all 11 medical centers in central Massachusetts on a biennial basis between 1986 and 2011. Multivariable adjusted logistic regression modeling was used to examine trends in hospital IRs and CFRs of VT and VF complicating AMI.

RESULTS

The median age of the study population was 71 years, 57.9% were men, and 94.7% were white. The hospital IRs declined from 14.3% in 1986/1988 to 10.5% in 2009/2011 for VT and from 8.2% to 1.7% for VF. The in-hospital CFRs declined from 27.7% to 6.9% for VT and from 49.6% to 36.0% for VF between 1986/1988 and 2009/2011, respectively. The IRs of both early (<48 hours) and late VT and VF declined over time, with greater declines in those of late VT and VF. The incidence rates of VT declined similarly for patients with either an ST-segment elevation myocardial infarction (STEMI) or non-STEMI, whereas they only declined in those with VF and a STEMI.

CONCLUSIONS

The hospital IRs and CHRs of VT and VF complicating AMI have declined over time, likely because of changes in acute monitoring and treatment practices. Despite these encouraging trends, efforts remain needed to identify patients at risk for these serious ventricular arrhythmias so that preventive and treatment strategies might be implemented as necessary.

Customers' satisfaction about prehospital emergency medical services in Lorestan, Iran

Introduction

Patient’s satisfaction with health care in ambulance services is an important quality indicator and a helpful tool for managers of prehospital emergency services. This study aimed to measure patient satisfaction with health provided by prehospital emergency medical services (EMS) in Lorestan, Iran.

Methods

This cross-sectional study was conducted on patients (n=450) transferred by EMS to hospitals of Lorestan University of Medical Sciences in a two-year period (2013–2014). Data collection was performed by patient questionnaire, which is a standard LKFR tool. Validity and reliability of the instrument was confirmed by scientific method. Collected data were analyzed by SPSS Version 19. Descriptive and inferential statistics such as Chi-square, paired-samples t-test, independent-samples t-test, ANOVA, Pearson’s product-moment correlation coefficient, and Fisher’s exact test were used.

Results

One hundred ninety-two (42.8%) and 257 (57.2%) patients were female and male, respectively (mean: 41 years, r: 37–83). Patient satisfaction of the dispatcher was good, and satisfaction level in regards to the technicians’ performance, physical situation, and facilities inside the ambulance was moderate. The Wilcoxon test did not show any significant difference between pain severity before and after arriving EMS in the cardiac and respiratory patients (p=0.691), but severity of pain in orthopedic patients after arriving EMS was decreased (p=0.001). Cardiac and respiratory patients had low satisfaction of EMS, and the Chi-square test was significant (p=0.001). Orthopedic patients had the most satisfaction of EMS.

Conclusion

Generally, patients’ satisfaction of EMS was low. Satisfaction with pain relief in orthopedic patients was better than pain relief in cardiac and respiratory patients. It is recommended to take necessary actions to improve the level of patient satisfaction of EMS.

Incidence, prognosis, and factors associated with cardiac arrest in patients hospitalized with acute coronary syndromes (the Global Registry of Acute Coronary Events Registry)

OBJECTIVES

Contemporary data are lacking with respect to the incidence rates of, factors associated with, and impact of cardiac arrest from ventricular fibrillation or tachycardia (VF-CA) on hospital survival in patients admitted with an acute coronary syndrome (ACS). The objectives of this multinational study were to characterize trends in the magnitude of in-hospital VF-CA complicating an ACS and to describe its impact over time on hospital prognosis.

METHODS

In 59 161 patients enrolled in the Global Registry of Acute Coronary Events Study between 2000 and 2007, we determined the incidence, prognosis, and factors associated with VF-CA.

RESULTS

Overall, 3618 patients (6.2%) developed VF-CA during their hospitalization for an ACS. Incidence rates of VF-CA declined over time. Patients who experienced VF-CA were on average older and had a greater burden of cardiovascular disease, yet were less likely to receive evidence-based cardiac therapies than patients in whom VF-CA did not occur. Hospital death rates were 55.3% and 1.5% in patients with and without VF-CA, respectively. There was a greater than 50% decline in the hospital death rates associated with VF-CA during the years under study. Patients with a VF-CA occurring after 48 h were at especially high risk for dying during hospitalization (82.8%).

CONCLUSION

Despite reductions in the magnitude of, and short-term mortality from, VF-CA, VF-CA continues to exert an adverse effect on survival among patients hospitalized with an ACS. Opportunities exist to improve the identification and treatment of ACS patients at risk for VF-CA to reduce the incidence of, and mortality from, this serious arrhythmic disturbance.

Thirty-year trends (1975-2005) in the magnitude, patient characteristics, and hospital outcomes of patients with acute myocardial infarction complicated by ventricular fibrillation

Limited contemporary data are available describing the incidence rates, hospital prognosis, and factors associated with the occurrence of ventricular fibrillation (VF) in patients hospitalized with acute myocardial infarction (AMI). The objectives of our study were to examine 3-decade-long trends (1975 to 2005) in the magnitude, predictors, and hospital case-fatality rates associated with VF in residents of a large New England metropolitan area hospitalized at all area medical centers with an uncomplicated AMI. The study population consisted of 7,472 residents of the Worcester (Massachusetts) metropolitan area hospitalized with an uncomplicated AMI in 15 annual periods from 1975 to 2005. The overall proportion of patients who developed VF was 4.2%. The incidence rates of VF remained stable from 1975 to 1995 but decreased thereafter, reaching their lowest frequency in 2005 (1.9%). Hospital case-fatality rates were significantly higher in patients with (40.9%) compared with those without (2.5%) VF. Decreases in hospital death rates over time were observed in patients with and without VF, with the decreases in death rates being greater for patients with VF. Patients who developed a Q-wave MI or a left or right bundle branch block were at particularly increased risk for developing VF. In conclusion, our results indicate that the incidence and hospital death rates associated with VF have decreased during recent years.

Early sustained ventricular arrhythmias complicating acute myocardial infarction

OBJECTIVE

Sustained ventricular arrhythmias complicate 2% to 20% of acute myocardial infarctions (MIs) and are associated with increased in-hospital mortality. However, it remains unclear whether successful mechanical revascularization improves outcomes in these patients. The objective of this analysis was to identify predictors of sustained ventricular arrhythmias after acute MI and to determine the influence of successful revascularization on in-hospital mortality.

METHODS

We conducted a retrospective cohort study of all patients who underwent percutaneous coronary intervention for acute MI in New York State between 1997 and 1999.

RESULTS

Of the 9015 patients who underwent percutaneous coronary intervention for acute MI, 472 (5.2%) developed sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) before revascularization. After multivariable adjustment, independent predictors of sustained VT/VF included cardiogenic shock (odds ratio [OR], 4.10; 95% confidence interval [CI], 3.20-5.58; P <.001), heart failure (OR, 2.86; 95% CI, 2.24-3.67: P <.001), chronic kidney disease (OR, 2.58; 95% CI, 1.27-5.23; P=.009), and presentation within 6 hours of symptom onset (OR, 1.46; 95% CI, 1.18-1.81; P=.001). Patients with sustained VT/VF had greater in-hospital mortality (16.3% vs 3.7%, P <.001). Although successful percutaneous coronary intervention was associated with decreased in-hospital mortality in patients with VT/VF (P <.001), patients with sustained VT/VF and successful revascularization experienced increased mortality compared with patients without sustained ventricular arrhythmias (P <.001).

CONCLUSION

Among patients undergoing percutaneous coronary intervention for acute MI, sustained VT/VF remains a significant complication associated with a 4-fold increased risk of in-hospital mortality. Early mortality is reduced after successful percutaneous coronary intervention, but remains elevated in this high-risk group.

Sustained ventricular tachycardia as a marker of inadequate myocardial perfusion during the acute phase of myocardial infarction

BACKGROUND

Sustained ventricular tachycardia (VT) complicating the acute phase of myocardial infarction (AMI) is a quite rare event but with short-term unfavorable prognosis. The clinical characteristics as well as the therapeutic implications have not yet been well defined.

HYPOTHESIS

This paper attempts to prove that VT may be considered a marker of inadequate myocardial perfusion after thrombolysis.

METHODS

To assess the clinic-electroangiographic characteristics and prognosis of patients with VT occurring within the first 4 days of an AMI, a case-control study was carried out in 23 patients from a total of 1,100 patients (1.9%) hospitalized with AMI between March 1993 and July 1997. These patients were compared with a control group of 131 patients hospitalized consecutively. A statistical analysis was made using the chi-square test, t-test, and logistic regression.

RESULTS

There were no differences among groups with regard to age, gender, and area of necrosis. Average time for the onset of VT was 26 h (range 0-92 h). Sixteen patients underwent coronary angiography: 4 patients had left main coronary artery disease, 2 had single-vessel disease, 8 had lesions in two vessels, and 2 had triple-vessel disease. Univariate analysis showed that patients with VT had a higher incidence of creatine phosphokinase (CPK)-MB peak > 300 UI/l (61 vs. 30%; p<0.001), more frequent occurrence of previous AMI (48 vs. 17%; p<0.001), and acute intraventricular conduction disorders (26 vs. 4%; p<0.001). Furthermore, these patients suffered ischemia previous to VT more frequently (65 vs. 11%; p<0.0001), and had a greater mortality rate than that in the control group (35 vs. 4%; p<0.0001). In the multivariant analysis, the variables related to the occurrence of VT were CPK-MB peak > 300 IU/l (OR 5.9; 95% CI 1.6-21), acute intraventricular conduction disorders (OR 9.02; 95% CI 1.7-48), and ischemia immediately prior to VT (odds ratio [OR] 19.64; 95% confidence interval [CI] 5.3-73).

CONCLUSIONS

Ventricular tachycardia may be considered a marker of inadequate myocardial perfusion after thrombolysis; therefore, a more aggressive revascularization treatment in these patients would be advisable. The profile of patients with AMI, hospitalized in the coronary care unit, who will likely suffer from VT is previous AMI, CPK-MB peak > 300, acute intraventricular conduction disorders, Killip > I, and ischemia previous to VT.

Ventricular arrhythmias after acute myocardial infarction: a 20-year community study

BACKGROUND

Although myocardial infarction (MI) severity is declining, the occurrence of ventricular arrhythmia (VA) after MI and its effect on outcome is unknown. This study was undertaken to examine the frequency and timing of VA and the effect of VA on mortality after MI.

METHODS

Myocardial infarctions recorded between 1979 and 1998 were validated. Baseline characteristics, occurrence of VA, and survival were determined. Ventricular arrhythmias were categorized as primary ventricular fibrillation (VF), nonprimary VF, and ventricular tachycardia (VT). Logistic regression was used to analyze associations between VA and baseline characteristics. Temporal trends were assessed with the Mantel-Haenszel chi2. Survival was analyzed with the Kaplan-Meier method. Proportional hazards regression was used to examine the association between death and occurrence of VA.

RESULTS

Among 2317 persons with incident MI, 7.5% experienced VA (3.6% nonprimary VF, 2.1% primary VF, 1.8% VT). Ventricular arrhythmia-associated factors were younger age, female sex, higher Killip class, ST elevation, and atrial fibrillation. Ventricular arrhythmias were associated with increased risk of death at 30 days.

CONCLUSION

Ventricular arrhythmias after MI are relatively common, particularly among persons with more severe MI and no prior history of coronary disease. Over time, the incidence of VF declined, whereas VT did not change. Ventricular arrhythmia after MI was associated with a 6-fold increase in morality. Thus, identification of high-risk MI survivors and prevention of VA could markedly improve outcomes. Further studies are needed to determine the cause of the shift in distribution of VA subtype.

Arrhythmic complications of acute coronary syndromes

Cardiac arrhythmias routinely manifest during or following an acute coronary syndrome (ACS). Although the incidence of arrhythmia is directly related to the type of ACS the patient is experiencing, the clinician needs to be cautious with all patients in these categories. As an example, nearly 90% of patients who experience acute myocardial infarction (AMI) develop some cardiac rhythm abnormality and 25% have a cardiac conduction disturbance within 24 hours of infarct onset. In this patient population, the incidence of serious arrhythmias, such as ventricular fibrillation (4.5%) ,is greatest in the first hour of an AMI and declines rapidly thereafter. This article addresses the identification and treatment of arrhythmias and conduction disturbances that complicate the course of patients who have ACS, particularly AMI and thrombolysis. Emphasis is placed on mechanisms and therapeutic strategies.

Prognostic implications of ventricular fibrillation in acute myocardial infarction: new strategies required for further mortality reduction

OBJECTIVE

To determine the changing risk of ventricular fibrillation, the prognostic implications, and the potential long term prognostic benefit of earlier hospital admission, after acute myocardial infarction.

DESIGN

Prospective observational study.

SETTING

A district general hospital in east London.

PATIENTS

1225 consecutive patients admitted to a coronary care unit with acute myocardial infarction.

MAIN OUTCOME MEASURES

Time of onset of pain and ventricular fibrillation, and long term survival of patients admitted with acute myocardial infarction.

RESULTS

The rate of ventricular fibrillation in these hospital inpatients was high in the first hour from onset of pain (118 events/1000 persons/h; 95% confidence interval (CI) 50.7 to 231) and fell rapidly to an almost constant low level by six hours; 27.4% of patients with early ventricular fibrillation died in hospital, compared with 11.6% of those without (p < 0.0001), but mortality in patients who survived to hospital discharge was not altered by early ventricular fibrillation (five year survival: 75.0% (95% CI 60.0% to 84.8%) with ventricular fibrillation v 73.3% (95% CI 69.6% to 76.6%) without ventricular fibrillation).

CONCLUSIONS

Patients successfully resuscitated from early ventricular fibrillation have the same prognosis as those without ventricular fibrillation after acute myocardial infarction. Faster access to facilities for resuscitation must be achieved if major improvements in the persistently high case fatality of patients after acute myocardial infarction are to be made.

Changes over time in the incidence and case-fatality rates of primary ventricular fibrillation complicating acute myocardial infarction: perspectives from the Worcester Heart Attack Study

BACKGROUND

Limited population-based data are available that describe temporal and recent trends in the incidence and case-fatality rates in patients with primary ventricular fibrillation (VF) complicating acute myocardial infarction (AMI). The purpose of this study was to describe changes over a 22-year period (1975 through 1997) in the incidence and hospital case-fatality rates of primary VF complicating AMI from a multihospital, community-wide perspective.

METHODS AND RESULTS

This was an observational study of metropolitan Worcester residents hospitalized with a validated uncomplicated AMI (n = 5020) in all hospitals in the Worcester, Massachusetts, metropolitan area (1990 census population = 437,000) during 11 1-year periods between 1975 and 1997. The overall incidence rate of primary VF complicating AMI was 4.7%. The crude as well as multivariable adjusted odds of the development of VF did not change significantly over the 22-year period under study. The overall in-hospital case-fatality rate of patients with primary VF was 44%, which was significantly greater in comparison with AMI patients in whom VF did not develop (5%). Hospital mortality rates associated with primary VF declined over time. Improved survival was observed in patients who had primary VF in the 1990s after adjusting for potential prognostic confounders.

CONCLUSIONS

The results of this community-wide study failed to indicate changes over time in the incidence rates of primary VF in patients hospitalized with AMI between 1975 and 1997. On the other hand, hospital death rates in patients with primary VF have shown encouraging declines during more recent periods. These mortality trends are likely to be the results of improvements in the treatment and more careful surveillance of patients with AMI.

A two-decades (1975 to 1995) long experience in the incidence, in-hospital and long-term case-fatality rates of acute myocardial infarction: a community-wide perspective

OBJECTIVES

The purpose of the present study is to describe changes over two decades (1975 to 1995) in the incidence, in-hospital and long-term case-fatality rates associated with acute myocardial infarction (AMI) from a multihospital community-wide perspective.

BACKGROUND

Despite the magnitude of, and mortality associated with acute myocardial infarction (AMI), relatively limited population-based data are available to describe recent and temporal trends in the attack and case-fatality rates associated with AMI from a representative population-based perspective.

METHODS

The community-based study included 5,270 residents of the Worcester, Massachusetts, metropolitan area hospitalized with confirmed initial AMI in all metropolitan Worcester, Massachusetts, hospitals (1990 census population = 437,000) in 10 one-year periods between 1975 and 1995.

RESULTS

The age-adjusted incidence rates of initial AMI increased between 1975 (244 per 100,000) and 1981 (272 per 100,000), after which time these rates declined through 1995 (184 per 100,000). The crude and multivariable-adjusted in-hospital case-fatality rates exhibited a consistent decline between 1975/1978 (17.8%), 1986/1988 (17.0%) and 1993/1995 (11.7%). Although there were no statistically significant differences in the unadjusted long-term case-fatality rates of discharged hospital survivors over the periods under study, declines in the multivariable-adjusted risk of dying within the first year after hospital discharge were observed between the earliest and most recently discharged patients with AMI.

CONCLUSIONS

The results of this population-based study of patients with validated initial AMI provide encouragement for efforts directed at the primary and secondary prevention of AMI given declining incidence and case-fatality rates.

Incidence and prognosis of early primary ventricular fibrillation in acute myocardial infarction--results of the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico (GISSI-2) database

Primary ventricular fibrillation (VF) complicating acute myocardial infarction (MI) predicts short-term mortality. The broad category of patients with primary VF might include subgroups with different outcomes. It is still not certain whether early-onset (< or =4 hours) primary VF is a risk predictor, and information on correlates of these early fibrillations is scarce. This study sought to prospectively analyze the incidence and prognosis of early, as opposed to late (time window >4 to 48 hours) primary VF and retrospectively identify predisposing factors for early-onset primary VF. We analyzed the incidence and recurrence rate of early and late primary VF in 9,720 patients with a first acute MI, treated with thrombolytics, enrolled in the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico (GISSI)-2 trial. The independent prognostic significance of early and late primary VF was assessed by logistic regression analysis. The incidence rates of early and late primary VF were 3.1% and 0.6%, respectively; recurrence rates were 11% and 15%, respectively. The 2 variables most closely related to early primary VF were hypokalemia and systolic blood pressure < 120 mm Hg on admission. Patients with early primary VF had a more complicated in-hospital course than matched controls. Both early (odds ratio [OR] 2.47, 95% confidence interval [CI] 1.48 to 4.13) and late primary VF (OR 3.97, 95% CI 1.51 to 10.48) were independent predictors of in-hospital mortality. Postdischarge to 6-month death rates were similar for both primary VF subgroups and controls. Primary VF, irrespective of its timing, was an independent predictor of in-hospital mortality. Postdischarge to 6-month prognosis was unaffected by the occurrence of either early or late primary VF.

Sex differences in symptom presentation associated with acute myocardial infarction: a population-based perspective

OBJECTIVES

To describe sex differences in symptom presentation after acute myocardial infarction (AMI) while controlling for differences in age and other potentially confounding factors.

BACKGROUND

Although several studies have examined sex differences in diagnosis, management, and survival after AMI, limited data exist about possible sex differences in symptom presentation in the setting of AMI.

METHODS

Community-based study of patients hospitalized with confirmed AMI in all 16 metropolitan Worcester, Mass., hospitals (1990 census population = 437,000). Men (n = 810) and women (n = 550) hospitalized with validated AMI in 1986 and 1988 comprised the study sample.

RESULTS

After simultaneously controlling for age, medical history, and AMI characteristics through regression modeling, men were significantly less likely to complain of neck pain (adjusted odds ratio (OR) = 0.52; 95% CI: 0.35, 0.78), back pain (OR = 0.38; 95% CI: 0.26, 0.56), jaw pain (OR = 0.50; 95% CI: 0.31, 0.81), and nausea (O.R. = 0.58; 95% CI: 0.45, 0.75) than women. Conversely, men were significantly more likely to report diaphoresis (OR = 1.27; 95% CI: 1.00, 1.61) than women. There were no statistically significant sex differences in complaints of chest pain though men were more likely to complain of this symptom.

CONCLUSIONS

The results of this population-based observational study suggest differences in symptom presentation in men and women hospitalized with AMI. These findings have implications for public and health care provider education concerning recognition of sex differences in AMI-related symptoms and health care seeking behaviors.

Arrhythmias associated with acute myocardial infarction and thrombolysis

Ninety percent of patients with acute myocardial infarction have some cardiac rhythm abnormality, and approximately twenty-five percent have cardiac conduction disturbance within 24 hours following infarct onset. Almost any rhythm disturbance can be associated with acute myocardial infarction, including bradyarrhythmias, supraventricular tachyarrhythmias, ventricular arrhythmias, and atrioventricular block. With the advent of thrombolytic therapy, it was found that some rhythm disturbances in patients with acute myocardial infarction may be related to successful coronary artery reperfusion. This article addresses the role and treatment of arrhythmias and conduction disturbances that complicate the course of patients with acute infarction and thrombolysis.

Comparison of patients with acute myocardial infarction with and without ventricular fibrillation

Among 1,590 patients with acute myocardial infarction from 1990 to 1994, the rate of primary ventricular fibrillation was 3.6%. The prevalence of smoking, complete left bundle branch block, hypokalemia, and decreased left ventricular function was higher in patients with ventricular fibrillation while those on thrombolytic therapy and those with non-Q-wave myocardial infarction were significantly lower.

Effect of elevated leukocyte count on in-hospital mortality following acute myocardial infarction

The peripheral white blood cell count on presentation with acute myocardial infarction directly correlates with short-term in-hospital mortality. This association is independent of other prognostic factors, including extent and size of the acute myocardial infarction.