Early and late advanced atrioventricular block in acute inferior myocardial infarction

Decision tree model for predicting in-hospital cardiac arrest among patients admitted with acute coronary syndrome

BACKGROUND

In-hospital cardiac arrest (IHCA) may be preventable, with patients often showing signs of physiological deterioration before an event. Our objective was to develop and validate a simple clinical prediction model to identify the IHCA risk among cardiac arrest (CA) patients hospitalized with acute coronary syndrome (ACS).

HYPOTHESIS

A predicting model could help to identify the risk of IHCA among patients admitted with ACS.

METHODS

We conducted a case-control study and analyzed 21 337 adult ACS patients, of whom 164 had experienced CA. Vital signs, demographic, and laboratory data were extracted from the electronic health record. Decision tree analysis was applied with 10-fold cross-validation to predict the risk of IHCA.

RESULTS

The decision tree analysis detected seven explanatory variables, and the variables' importance is as follows: VitalPAC Early Warning Score (ViEWS), fatal arrhythmia, Killip class, cardiac troponin I, blood urea nitrogen, age, and diabetes. The development decision tree model demonstrated a sensitivity of 0.762, a specificity of 0.882, and an area under the receiver operating characteristic curve (AUC) of 0.844 (95% CI, 0.805 to 0.849). A 10-fold cross-validated risk estimate was 0.198, while the optimism-corrected AUC was 0.823 (95% CI, 0.786 to 0.860).

CONCLUSIONS

We have developed and internally validated a good discrimination decision tree model to predict the risk of IHCA. This simple prediction model may provide healthcare workers with a practical bedside tool and could positively impact decision-making with regard to deteriorating patients with ACS.

Bloqueo auriculoventricular en la angina inestable. Resultados del registro ARIAM

OBJECTIVE

Describe the frequency of high degree atrioventricular block (HDAVB) in patients with unstable angina (UA), analyze the variables associated with their appearance and evaluate whether HDAVB is independently associated with increased mortality or increased length of ICU stay.

DESIGN

Retrospective descriptive study of patients with UA included in the ARIAM registry.

SETTING

ICUs from 129 hospitals in Spain.

PATIENTS

From June 1996 to December 2003 a total of 14,096 patients were included in the ARIAM registry with a diagnosis of UA.

MAIN VARIABLES OF INTEREST

Variables associated with the development of HDAVB, variables associated with the mortality of patients with UA, variables associated with the length of ICU stay of patients with UA.

RESULTS

HDAVB frequency was 1%. Development of HDAVB was independently associated with the Killip classification and the presence of sustained ventricular tachycardia or ventricular fibrillation. Crude mortality of patients was significantly increased when HDAVB was present (9% versus 1%, p < 0,001). When adjusted for other variables, HDAVB was not associated with increased mortality. Development of HDAVB in patients with UA was independently associated with an increase in the length of ICU stay (adjusted odds ratio 1.89: 95% confidence interval: 1.33-5.69).

CONCLUSIONS

Patients with UA complicated with HDAVB represent a high-risk population with an increased ICU stay.

Fatality of myocardial infarction in relation to the coronary anatomy: role of culprit lesion location

OBJECTIVE

We set out to study the effect of the location of the culprit coronary lesion on myocardial infarction (MI) fatality by combining data from MI survivors in the coronary care unit (CCU) and autopsied patients with pre-hospital fatal MI.

DESIGN

We studied two simultaneous series of men under 70 years with fatal pre-hospital MI (n = 36) and men admitted for acute ST-elevation-MI (n = 92). The culprit lesion was identified by the presence of thrombus at autopsy and by coronary angiography in patients admitted to the CCU.

RESULTS

The culprit lesion was located in the right coronary artery (RCA) in 22 (61%) of 36 men with fatal MI compared to 30 (33%) of 92 men with non-fatal MI (P = 0.01). Seventy-three percent of fatal RCA occlusions were proximal as opposed to only 30% of non-fatal RCA occlusions (P < 0.001). Forty-four percent of all fatal MI were due to proximal RCA occlusion as opposed to only 10% of non-fatal MI (P < 0.005).

CONCLUSIONS

Proximal RCA occlusions were very often found among men with fatal pre-hospital MI, whereas left-sided coronary occlusions were significantly more frequent in hospital-admitted survivors of MI. Left-sided coronary occlusions may be associated with a more favourable pre-hospital phase of acute MI compared to proximal RCA occlusions.

Prognostic importance of complete atrioventricular block complicating acute myocardial infarction

Third-degree atrioventricular block after acute myocardial infarction is considered to have prognostic importance. However, its importance in conjunction with thrombolytic therapy and its relation to left ventricular function remains uncertain. This report also outlines an important distinction between atrioventricular block in the setting of anterior and inferior wall acute myocardial infarction, with profound clinical and prognostic implications.

Acute myocardial infarction complicated by heart block in the elderly: prevalence and outcomes

BACKGROUND

Although second- and third-degree heart block (HB) are common conduction disorders associated with acute myocardial infarction (MI), patient characteristics and HBs association with outcomes, particularly among the elderly, remain poorly defined.

METHODS

We evaluated 106,780 Medicare beneficiaries aged 65 years and older treated for acute MI between January 1994 and February 1996 for development of HB. HB and non-HB patients were compared by univariate analysis, and the influence of HB on outcomes was evaluated by unadjusted and multiple logistic regression.

RESULTS

HB was documented in 5048 (4.7%) patients; 1646 presented with HB and 3402 developed HB during hospitalization. HB was more common among patients with inferior infarctions than anterior infarctions (7.3% vs 3.0%, P =.001), particularly the cohort of patients with inferior MI treated with reperfusion therapy (8.3%). HB patients had higher rates of in-hospital mortality (29.6% vs. 17.5% vs. non-HB patients, P =.001). After adjustment for demographic and clinical factors, HB remained an independent predictor of in-hospital mortality (relative risk [RR] 1.41, 95% confidence interval [CI] 1. 34-1.48), but HB had no prognostic significance at 1 year among hospital survivors (RR 0.94, 95% CI 0.88-1.01). Mortality risks varied on the basis of MI location. Both anterior MI (RR 1.46, 95% CI 1.30-1.63) and inferior MI (RR 1.52, 95% CI 1.39-1.66) patients with HB had increased risks of in-hospital mortality. There was a trend toward increased mortality among patients with anterior MI (RR 1.15, 95% CI 0.99-1.32) at 1 year, whereas those with inferior MI were at lower risk (RR 0.83, 95% CI 0.75-0.98).

CONCLUSIONS

HB is a common complication of acute MI in elderly patients, particularly among patients with inferior MIs who received reperfusion therapy. HB is independently associated with short-term but not long-term mortality.

Effect of aminophylline in patients with atropine-resistant late advanced atrioventricular block during acute inferior myocardial infarction

BACKGROUND

Advanced atrioventricular (AV) block is a frequent complication in patients with acute inferior myocardial infarction (AIMI). This conduction abnormality is associated with narrow QRS complex in conducted or junctional escape beats, suggesting that the site of block is the AV node; however, its pathophysiology has not been properly established.

HYPOTHESIS

This study investigated the effect of aminophylline in eight patients (5 men, 3 women, age range 51 to 78 years, mean 67.5 +/- 8.8 years) with atropine-resistant late advanced AV block during AIMI.

METHODS

Advanced AV block was late in appearance in all patients, starting 2 to 5 days after AIMI, and consisted of second-degree Mobitz II type in two patients and of complete AV block in six patients; all patients had narrow QRS complexes. Before aminophylline administration, all patients had a temporary pacemaker installed which was switched off throughout the study. They were given intravenous atropine (1 mg) that was found to be ineffective. One-half h after atropine, the first aminophylline injection (240 mg) was given intravenously over 10 min. One h following the first injection, a second aminophylline dose (240 mg) was administered. Electrocardiographic rhythm strips were obtained before and after drug administration, and the type of AV block and atrial and ventricular rate were noted.

RESULTS

Aminophylline restored 1:1 conduction with first-degree AV block in six patients, Mobitz I AV block in one patient, and normal sinus rhythm in one patient. Mean atrial and ventricular rates before aminophylline were 104 +/- 16 beats/min and 57 +/- 9 beats/min, respectively, and after drug administration 95 +/- 25 beats/min and 89 +/- 17 beats/min, respectively, (p = 0.012).

CONCLUSION

These results indicate that aminophylline improves AV conduction in atropine-resistant late advanced AV block complicating AIMI.