Can the mode of death be predicted in patients with angiographically documented coronary artery disease?
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Predicting sudden cardiac death is challenging. While factors like coronary disease and heart dysfunction predict overall cardiac mortality, they don't distinguish between sudden and non-sudden deaths. Prolonged QTc interval may indicate sudden death risk.
Area of Science:
- Cardiology
- Clinical Medicine
- Morticational Epidemiology
Background:
- Identifying predictors for sudden cardiac death (SCD) versus non-sudden cardiac death (NSCD) in high-risk patients is crucial for targeted interventions.
- Traditional risk factors for cardiac mortality do not consistently differentiate between SCD and NSCD.
Purpose of the Study:
- To investigate whether clinical, hemodynamic, and angiographic variables can predict sudden versus non-sudden cardiac death in high-risk patients.
- To explore the role of the corrected QT (QTc) interval in predicting cardiac death outcomes.
Main Methods:
- A cohort of 1157 high-risk patients underwent coronary angiography and were followed for an average of 46 months.
- 18 pre-defined risk variables were analyzed, and deaths were classified into sudden cardiac death, acute myocardial infarction, or non-cardiac causes.
- QTc interval was measured at baseline and, in a subset, before death.
Main Results:
- While older age, male sex, history of myocardial infarction, unstable angina, congestive heart failure, abnormal cardiothoracic ratio, multivessel disease, and impaired left ventricular function predicted overall cardiac mortality, they did not differentiate SCD from NSCD.
- Both SCD and NSCD groups showed depressed left ventricular function and multivessel coronary disease.
- Patients experiencing SCD had a lower incidence of new myocardial infarction or heart failure during follow-up compared to those dying from acute myocardial infarction.
- Prolongation of the QTc interval (≥440 ms) was significantly higher in patients experiencing sudden death during follow-up.
Conclusions:
- The severity of coronary artery disease and left ventricular dysfunction are linked to cardiac mortality but do not distinguish between sudden and non-sudden cardiac deaths.
- Patients experiencing sudden death are characterized by a low incidence of new myocardial infarction or congestive heart failure and a higher incidence of QTc interval prolongation.
Abstract:
To determine whether sudden versus non-sudden cardiac death could be predicted in high risk patients, 1157 medical patients were followed for an average of 46 months after a diagnostic coronary angiogram and 18 clinical, hemodynamic, and angiographic variables known to be associated with a high risk of mortality were analyzed. The total group of 141 deaths was classified into 3 subgroups: (1) 82 sudden deaths (less than 1 hour after onset of symptoms); (2) 46 deaths due to acute myocardial infarction with or without heart failure, and (3) 13 deaths unrelated to cardiac symptoms. In a subset of 64 patients, the duration of electrical systole (QTc) was calculated before angiography and before death. A comparison was made of QTc measurements at entry with QTc values of subjects with normal coronary arteries and normal left ventricular function. Deaths from cardiac causes could often be predicted from older age, male sex, history of myocardial infarction, unstable angina, congestive heart failure, abnormal cardiothoracic ratio, multivessel disease, abnormal left ventricular contraction, and abnormal ejection fraction. However, these variables did not discriminate between sudden and nonsudden cardiac deaths and both modes of death were characterized by depressed left ventricular function and multivessel coronary disease. During follow-up the incidence of acute myocardial infarction was not different in patients with cardiac and noncardiac deaths and in long-term survivors. However, patients dying from cardiac causes had a higher incidence of heart failure. Patients dying suddenly did not present new infarctions during follow-up whereas patients dying from acute myocardial infarction had a 13% incidence of prior infarction and a higher incidence of heart failure. In addition, QTc at entry was longer in nonsurvivors than in normal subjects (p less than 0.0001) and patients experiencing sudden death exhibited the highest incidence of QTc prolongation (greater than or equal to 440 ms) during follow-up (p less than 0.05). We conclude that: (1) although the severity of coronary disease and left ventricular dysfunction are closely related to cardiac mortality, they do not discriminate between sudden and nonsudden cardiac deaths; (2) patients experiencing sudden death are characterized by a low incidence of new myocardial infarction or congestive heart failure and prolongation of the QTc interval during follow-up.