Abstract 16129: Mechanical Alternans Associated With Ventricular Tachyarrhythmias
Alternans of calcium cycling is important for the development of ventricular tachyarrhythmias (VTs). We hypothesized that mechanical alternans (MA) predicts VTs in the cardiac intensive care unit (CCU) patients.
Methods: We prospectively studied 25 patients (mean age 56±14; 21 male [84%]) admitted to the CCU due to congestive heart failure (CHF) exacerbation (15 patients [60%]), acute myocardial infarction (3 patients [12%]), or VT storm / VF cardiac arrest (7 patients [28%]). Patients with pericardial effusion or valvular heart disease were excluded. Two-lead surface ECG simultaneously with pulmonary artery pressure via balloon directed catheter or arterial pressure via peripheral arterial line was recorded continuously for at least 12 hours. Time-domain method of MA detection was employed. Sustained MA was defined as MA that lasted for more than 20 beats with alternating pulse pressure greater than 4 mmHg.
Results: Recording of both pulmonary and systemic pressure was performed in 6 patients, pulmonary pressure in 5 patients, and systemic pressure in 14 patients. The total pressure monitoring time was 34±39 hours per patient. Sustained MA was observed in 8 patients (32%). On average 1.0±2.4 sustained MA per hour was observed, with alternating pulse pressure 48.8±25.2 mmHg that lasted for 24±1 beats. An example of pressure MA in a patient with subsequent sustained VT is shown in Figure 1. A trend of low EF in patients with sustained MA was observed (21.9±13.6 vs. 30.6±17.7 % P=0.193). No difference in indications for CCU admission among patients with sustained MA was noted. Two patients with sustained MA developed sustained VT with appropriate ICD shock during CCU stay. Extremely frequent non-sustained VT (≥50% of VT beats during 1 hour) was recorded in another patient with sustained MA. No VT/VF was observed in patients without MA.
Conclusions: MA was observed in CCU patients who subsequently developed sustained VT/VF. Further study of MA in this population is warranted.
- © 2010 by American Heart Association, Inc.