What percentage of community-based first myocardial infarctions (MIs) are fatal?

Percentage of Community-Based First Heart Attacks That Are Fatal

Community studies have consistently shown that the overall fatality rate of acute heart attacks in the first month is between 30% and 50%, with about half of these deaths occurring within the first 2 hours after symptom onset. 1, 2

Mortality Data Breakdown

The mortality of first myocardial infarctions can be analyzed from several perspectives:

Overall Community-Based Mortality

• 30-50% of all heart attacks in community settings are fatal within the first month 1
• Approximately half of these deaths (15-25%) occur within the first 2 hours after symptom onset 1
• This high initial mortality rate has remained relatively unchanged over the past 30 years 1, 2

Timing of Fatal Events

• The earliest phase (first 2 hours) is the most dangerous period, with the highest mortality rate 1
• Many victims die before reaching medical care, which is why community-based mortality rates are much higher than hospital-based rates 2

Contrast with Hospital-Based Mortality

• In-hospital mortality has decreased dramatically over time:
  • 25-30% before coronary care units (pre-1960s) 1
  • 18% in the mid-1980s (pre-thrombolytic era) 1
  • 6-7% with modern treatments (fibrinolysis, aspirin, coronary interventions) 1
  • 8.4% at 1 month in the European Heart Survey for ST-segment elevation acute coronary syndromes 1

Factors Influencing Mortality

Several factors affect the likelihood of a fatal outcome in first heart attacks:

Patient-Related Factors

• Age (older patients have higher mortality) 1
• Previous medical history (diabetes increases risk) 1
• Infarct location (anterior infarctions carry worse prognosis than inferior) 1
• Initial blood pressure (low BP indicates poorer outcomes) 1
• Killip class on admission (higher class indicates worse heart failure and higher mortality) 1
• Extent of ischemia as expressed by ST-segment elevation/depression 1

Healthcare System Factors

• Time to treatment (earlier treatment dramatically improves survival) 1
• Availability of emergency medical services 1
• Implementation of reperfusion strategies 1

Important Considerations

• The true natural history of myocardial infarction is difficult to establish due to:

  • Common occurrence of silent infarctions
  • Frequency of acute coronary death outside hospital
  • Varying methods used in diagnosis 1

• There are significant regional differences in 30-day acute MI hospital mortality and readmission rates 1

• While hospital-based mortality has decreased dramatically, community-based mortality remains high, highlighting the importance of early recognition and rapid emergency response 2

Clinical Implications

• Public education about heart attack symptoms is crucial since a substantial portion of deaths occur before patients reach the hospital 2
• The development of efficient emergency medical systems and networks between hospitals with various levels of technology is essential for improving outcomes 1
• Immediate reperfusion strategies have been shown to significantly reduce mortality 1

The persistent high community-based mortality rate of 30-50% underscores the critical importance of prevention, early recognition, and rapid access to emergency care for patients experiencing their first heart attack.