John DeCamilla

Ventricular ectopic beats and their relation to sudden and nonsudden cardiac death after myocardial infarction.

The role of ventricular ectopic beats (VEBs) in identifying patients who die of cardiac cause in the posthospital phase of myocardial infarction was evaluated in 940 patients who survived an acute coronary event. Six-hour Holter ECG recordings were obtained before hospital discharge, and VEBs were classified as complex (bigeminal, multiform, repetitive or R on T), simple (one or more VEBs that did not have complex patterns), or not present. Patients were followed 1-60 months (average 36 months) and cardiac mortality was categorized as sudden (⩾ I hour) or nonsudden (> I hour) among 98 witnessed cardiac deaths. Complex VEBs were associated with a significantly increased cardiac death rate, but did not discriminate between sudden and nonsudden death. Simple VEBs were associated with a 3-year cardiac mortality rate intermediate between those with complex and those with no VEBs. The relationship between complex VEBs and cardiac mortality was independent of 10 relevant clinical variables.

Clinical significance of ventricular tachycardia (3 beats or longer) detected during ambulatory monitoring after myocardial infarction.

SUMMARY Six-hour ECG recordings were performed every four months during follow-up periods (4-48 months) in 915 patients less than 66 years of age who survived the hospital phase of myocardial infarction. One hundred ninety-nine episodes of ventricular tachycardia (VT) were identified in 66 patients. Most patients (74%) had only one episode of VT. In 47% of the patients, the longest run of VT consisted of three ventricular premature beats in a row. A double set of control patients (N = 132) was assembled by matching each VT patient according to sex, admission date and VT recording date. The VT and control patients were similar in most clinical characteristics. However, VT patients had more severe cardiac disease (P < 0.05) and more evidence of ventricular irritability (P < 0.01) than their matched controls. The mortality rates in the VT and control groups were 16% (11/66) and 8% (11/132), respectively (P < 0.11). The risk of VT patients dying was 2.35 (95% confidence interval 0.82 to 6.77) times that of patients without VT. Life-table analysis of the survival of VT and control patients revealed a 48-month VT survival of 75% compared to 87% in the control group. Among those who died, the age, sex, cause of death, suddenness of death and mechanism of death were similar in the VT and control patients. Within the VT group, those who died had more severe underlying heart disease than the survivors. The occurrence of VT in the posthospital phase of myocardial infarction, while associated with a lower survival rate, does not indicate as much danger as generally assumed.

Survivorship patterns in the posthospital phase of myocardial infarction.

A prospective postinfarction follow-up study was used to identify subsets of patients with different survival patterns. Nine hundred forty patients who survived the hospital phase of an acute myocardial infarction were followed for 12-60 months. During the 5-year follow-up, 115 patients died of cardiac causes. Univariate analysis showed that prior myocardial infarction (PMI), left ventricular dysfunction (LVD) in the CCU, one or more ventricular premature depolarizations (VPDs) on a 6-hour Holter recording, and anterior myocardial infarction were significantly (p < 0.01) more frequent in patients who died of cardiac causes than in survivors. Survivorship analyses revealed a variety of survival patterns, depending on the presence or absence of the risk factors PMI, LVD, VPD and anterior infarction, as well as their interactive combinations. A combination of anterior infarction with LVD and VPDs identified a high-risk subset that made up 15% of the myocardial infarction population, and this group had 6-month and 3-year survival rates of 85% and 70%, respectively. After we excluded the high-risk subset, PMI, LVD and VPD each had significant yet independent influence on survival, with PMI having a greater effect on mortality than either LVD or VPDs. A low-risk subset that made up 24% of the population was identified by the absence of PMI, LVD and VPDs, and this group had a 3-year survival of 94%.

The Posthospital Phase of Myocardial Infarction Identification of Patients with Increased Mortality Risk

A prospective follow-up study was carried out on 100 patients recovering from acute myocardial infarction in order to develop a method for identifying those patients who are at high risk of late cardiac death. Variables, which were recorded just prior to the patients hospital discharge after the acute attack, included six rhythm parameters from a six-hour tape ECG recording, three indices of severity of the acute coronary event, and seven nonspecific variables. Seventy-nine of the 100 patients survived a two-year follow-up, and 17 of 21 patients who died succumbed from cardiac-related problems. A stepwise discriminant analysis program was used to derive a formula which would predict the likelihood of surviving two years after a myocardial infarction. The population was divided into two groups on the basis of the presence (Group A, N = 67) or absence (Group B, N = 29) of ventricular premature beats on the initial ECG tape recording. In Group A, 91% of both the survivors and nonsurvivors were correctly identified by a discriminant combination of three arrhythmia parameters and age. In Group B, 75% of the survivors and 100% of the nonsurvivors were properly classified simply from age and one index of severity.

The early posthospital phase of myocardial infarction. Prognostic stratification.

Prognostic stratification was carried out on 518 patients ≤ 65 years of age who were discharged from the hospital following a definite or probable acute myocardial infarction and followed for four months. The total population was made up of 272 patients hospitalzed in 1973 and 246 patients hospitalized in 1974; one hundred and forty-two variables were collected on each patient. The clinical characteristics of the 1973 and 1974 populations were remarkably similar, and both groups had a four-month posthospital cardiac mortality rate of 4%. Two prognostic stratification schemes were developed on the 1973 population which identified low and high risk groups with meaningfully different four-month cardiac death rates. Both stratification schemes were tested on the 1974 population, and one of the two schemes was validated as identifying a significantly increased cardiac mortality rate in the high as opposed to the low risk group. The four-month posthospital cardiac mortality rate was 3% in the low and 14% in the high risk group (Z = 2.70, P < 0.003). The high risk group was characterized by two or more of the following characteristics: 1) history of angina at ordinary levels of activity or at rest; 2) CCU hypotension and/or congestive heart failure; 3) ventricular premature beat frequency ≥ 20/hr on a sixhour electrocardiographic tape recording. The low risk group had none or only one of the above characteristics. The prognostic power of this stratification scheme is such that sixteen percent of the posthospital population can be identified as high risk, and this subgroup contains forty-six percent of the patients who die of cardiac cause in the four-month posthospital interval.

Ventricular Arrhythmias 3 Weeks After Acute Myocardial Infarction

Abstract One hundred patients who were convalescing from a definite or probable acute myocardial infarction had a 6-hour ECG rhythm tape recording made just before contemplated discharge from the h...