Wearable defibrillator use in heart failure (WIF): results of a prospective registry.

BACKGROUND: Heart failure (HF) patients have a high risk of death, and implantable cardioverter defibrillators (ICDs) are effective in preventing sudden cardiac death (SCD). However, a certain percentage of patients may not be immediate candidates for ICDs, particularly those having a short duration of risk or an uncertain amount of risk. This includes the newly diagnosed patients, as well as those on the cardiac transplant list or NYHA class IV heart failure patients who do not already have an ICD. In these patients, a wearable cardioverter defibrillator (WCD) may be used until long term risk of SCD is defined. The purpose of this study was to determine the incidence of SCD in this population, and the efficacy of early defibrillation by a WCD. METHODS: Ten enrolling centers identified 89 eligible HF patients who were either listed for cardiac transplantation, diagnosed with dilated cardiomyopathy, or receiving inotropic medications. Data collected included medical history, device records, and outcomes (including 90 day mortality). RESULTS: Out of 89 patients, final data on 82 patients has been collected. Patients wore the device for 75±58 days. Mean age was 56.8±13.2, and 72% were male. Most patients (98.8%) were diagnosed with dilated cardiomyopathy with a low ejection fraction (<40%) and twelve were listed for cardiac transplantation. Four patients were on inotropes. There were no sudden cardiac arrests or deaths during the study. Interestingly, 41.5% of patients were much improved after WCD use, while 34.1% went on to receive an ICD. CONCLUSIONS: In conclusion, the WCD monitored HF patients until further assessment of risk. The leading reasons for end of WCD use were improvement in left ventricular ejection fraction (LVEF) or ICD implantation if there was no significant improvement in LVEF.

VO2 Max and anaerobic threshold in hypertension: a tissue Doppler study.

BACKGROUND: Hypertension can impair left ventricular (LV) relaxation causing shortness of breath and reduced exercise capacity, which may affect the clinical evaluation of the symptomatic hypertensive patient. In this study we used tissue Doppler imaging (TDI) to identify correlates of anaerobic threshold (AT) and maximum oxygen uptake (VO2 Max). Our goal was to assess the feasibility of TDI as a surrogate of functional capacity in hypertensive individuals. METHODS: We studied subjects without metabolic syndrome and with normal LV function (ejection fraction (EF) >50%). Traditional echocardiographic variables were obtained before and after a cardiopulmonary exercise test. Systolic (S) and diastolic (E'and A') myocardial velocities were measured at the basal septal (bs) and posterior (bp) walls. RESULTS: After multivariate analysis, resting E'bp (r =0.56, P < 0.002) and isovolumic relaxation time (IVRT) (r =-0.49, I < 0.03) correlated with VO2 Max, while A Valsalva correlated with AT (r =-0.46, P < 0.03). Peak stress E'/A'bp correlated with age and gender corrected METs (r =-0.63, P < 0.0004) and VO2 Max (r =-0.39, P< 0.04). CONCLUSIONS: Resting E'bp and peak stress E'/A'bp correlate with VO(2) Max in hypertensive patients. TDI may be an important tool when assessing symptoms in this population.