Burden of Arrhythmias in Acute Myocardial Infarction Complicated by Cardiogenic Shock

Abstract

There are limited data on arrhythmias in acute myocardial infarction with cardiogenic shock (AMI-CS). Using a 17-year AMI-CS population from the National Inpatient Sample, we identified common arrhythmias - atrial fibrillation (AF), atrial flutter, supraventricular tachycardia, ventricular tachycardia, ventricular fibrillation, and atrioventricular blocks (AVB). Admissions with concomitant cardiac surgery were excluded. Outcomes of interest included temporal trends, predictors, in-hospital mortality, and resource utilization in cohorts with and without arrhythmias. Of the 420,319 admissions with AMI-CS during 2000 to 2016, arrhythmias were noted in 213,718 (51%). AF (45%), ventricular tachycardia (35%) and ventricular fibrillation (30%) were the most common arrhythmias. Compared with those without, the cohort w`ith arrhythmias was more often male, of white race, with ST-segment elevation AMI-CS presentation, and had higher rates of cardiac arrest and acute organ failure (all p <0.001). Temporal trends of prevalence revealed a stable trend of atrial and ventricular arrhythmias and declining trend in AVB. The cohort with arrhythmias had higher unadjusted (42% vs 41%; odds ratio [OR] 1.03 [95% confidence interval 1.02 to 1.05]; p <0.001), but not adjusted (OR 1.01 [95% CI 0.99 to 1.03]; p = 0.22) in-hospital mortality compared with those without. The cohort with arrhythmias had longer hospital stay (9 ± 10 vs 7 ± 9 days; p <0.001) and higher hospitalization costs ($124,000 ± 146,000 vs $91,000 ± 115,000; p <0.001). In the cohort with arrhythmias, older age, female sex, non-white race, higher co-morbidity, presence of acute organ failure, and cardiac arrest, predicted higher in-hospital mortality. In conclusion, cardiac arrhythmias in AMI-CS are a marker of higher illness severity and are associated with greater resource utilization.

Figure 1.. Arrhythmias in AMI-CS

Cumulative arrhythmias in AMI-CS showing overlap and relative percentages between different arrhythmia categories and types in the arrhythmia cohort (N=213,718) Abbreviations: AF: atrial fibrillation; AFlut: atrial flutter; AMI: acute myocardial infarction; AVB: atrio-ventricular block; CS: cardiogenic shock; SVT: supraventricular tachycardia; VF: ventricular fibrillation; VT: ventricular tachycardia

Figure 2.. Trends in the prevalence of atrial, ventricular and AVB arrhythmias in AMI-CS

17-year unadjusted trends in the prevalence of atrial arrhythmias (A), ventricular arrhythmias (B), AVB and PPM (C); all p<0.001 for trend over time; D: Adjusted multivariate logistic regression for prevalence of atrial, ventricular and AVB arrhythmias temporal trends with 2000 as referent year; adjusted for age, sex, race, comorbidity, primary payer, socio-economic stratum, hospital characteristics, comorbidities, AMI type, acute organ failure, cardiac arrest, cardiac and non-cardiac procedures (p<0.001 for trend over time). Abbreviations: AF: atrial fibrillation; AFlut: atrial flutter; AMI: acute myocardial infarction; AVB: atrio-ventricular block; CS: cardiogenic shock; PPM: permanent pacemaker; SVT: supraventricular tachycardia; VF: ventricular fibrillation; VT: ventricular tachycardia

Figure 3.. Trends of in-hospital mortality in AMI-CS admissions with and without arrhythmias

A: Unadjusted in-hospital mortality in AMI-CS by year of admission, stratified by arrhythmias (p<0.001 for trend over time); D: Adjusted multivariate logistic regression for in-hospital mortality temporal trends stratified by arrhythmias with 2000 as referent year; adjusted for age, sex, race, comorbidity, primary payer, socio-economic stratum, hospital characteristics, comorbidities, AMI type, acute organ failure, cardiac arrest, cardiac and non-cardiac procedures (p<0.001 for trend over time). Abbreviations: AMI: acute myocardial infarction; CS: cardiogenic shock

Figure 4.. Adjusted odds ratio for in-hospital mortality in AMI admissions with arrhythmias

Odds ratio with 95% confidence interval using multivariable regression analysis for prediction of in-hospital mortality; for cohorts with multiple categories (i.e. age, sex, race, primary payer, CCI, SES, AMI type) the first category was used as reference category for calculating odds ratios Abbreviations: AMI: acute myocardial infarction; CCI: Charlson comorbidity index; CS: cardiogenic shock; IHDM: invasive hemodynamic monitoring; IMV: invasive mechanical ventilation; MCS: mechanical circulatory support; NSTEMI: non-ST-elevation myocardial infarction; PCI: percutaneous coronary intervention; SES: socio-economic status; STEMI: ST-elevation myocardial infarction