The predictive value of heart rate turbulence for ventricular systolic dysfunction and prognosis in the peri-infarction period

OBJECTIVES
This study was conducted to investigate the relationship between heart rate turbulence (HRT) and acute left ventricular systolic dysfunction due to ST-segment elevation acute myocardial infarction (STEMI).

STUDY DESIGN
The study included 50 consecutive patients with acute STEMI. All the patients received thrombolytic therapy on admission and underwent transthoracic echocardiographic (TTE) examination at the 24th hour of hospitalization. The patients were divided into two groups according to whether they had decreased or normal left ventricular ejection fraction (LVEF). There were 25 patients (mean age 48±9 years; LVEF: <55%) in group 1, and 25 patients (mean age 52±9 years; LVEF: ≥55%) in group 2. All the patients underwent 24-hour Holter monitoring after TTE to derive the two HRT parameters, turbulence onset (TO) and turbulence slope (TS), showing early acceleration and late deceleration phases, respectively.

RESULTS
Patients in group 1 exhibited a significantly higher mean TO (0.74±1.82% vs -2.35±1.48%, p<0.05) and a significantly lower LVEF (39.1±6.7% vs 57.2±5.3%, p<0.05). The other Holter and echocardiographic variables did not differ significantly between the two groups (p>0.05). An abnormal TO value (≥0%) was found to have sensitivity and specificity of 88% (p<0.05) in predicting acute left ventricular systolic dysfunction (LVEF<55%) during the peri-infarction period of STEMI.

CONCLUSION
Impaired TO may be used as a useful predictor of left ventricular systolic dysfunction and poor prognosis in the peri-infarction period of STEMI.