Heart rate turbulence in adults with repaired tetralogy of Fallot.

BACKGROUND: Tetralogy of Fallot (ToF) patients face an increased risk of sudden cardiac death late after repair. Heart rate turbulence (HRT) indices are well-known predictors of sudden cardiac death. We aimed to estimate whether HRT is impaired in repaired ToF patients compared to healthy controls and relate those HRT parameters to already recognized prognostic markers. METHODS: Continuous ECG recordings were performed in 19 patients late after ToF repair (36.3+/-12.4 years, 26.6+/-7.1 years after repair) and 20 age-matched healthy controls (40.8+/-8.1 years). Turbulence slope (TS) and onset (TO), frequency and time domain heart rate variability parameters and QRS duration were estimated. Volumes of the right (RV) and left ventricle (LV) and ejection fraction (EF) were assessed by cardiovascular magnetic resonance imaging. Cardiopulmonary exercise testing was used to estimate peak oxygen consumption (VO(2)) and VE/VCO(2) slope. RESULTS: TS (15.95+/-9.41 vs 28.73+/-12.24 ms/RRI, p=0.0007) and TO (-0.98+/-2.06% vs -3.45+/-3.25%, p=0.007) were found to be significantly different between ToF patients and controls. TO correlated with LVEF (r=0.47, p<0.05), LVSVi (r=0.50, p=0.03), RVEF (r=0.53, p=0.02), peak VO(2) (r=0.50, p=0.05), VE/VCO(2) slope (r=-0.55, p=0.03) and with heart rate variability frequency domain indices (log LF, r=0.47, p=0.04, log HF, r=0.56, p=0.01). CONCLUSION: HRT indices are impaired in ToF patients late after surgical repair compared to healthy controls and relate to coexisting haemodynamic, ventilatory and autonomic impairment. A clinical prognostic role of HRT may be speculated, which warrants further investigation.

Quantitative analysis of semi-supine exercise echocardiography--influence of age on myocardial Doppler imaging indices.

OBJECTIVES: This study was performed to evaluate the feasibility of quantitative analysis of exercise echocardiography using pulsed wave Doppler myocardial imaging (DMI) and to examine the relation between age and DMI parameters at rest and during graded exercise in normal subjects. METHODS AND RESULTS: Seventy-two healthy volunteers were divided into three age groups (group I, age < or = 40 years, group II, age 41 - 59 years and group III, age > or = 60 years), and underwent a semi-supine exercise echocardiogram. Peak systolic velocity (SV), time to peak SV (TPV), systolic velocity time integral (VTI) and peak diastolic velocities (VE and VA) were measured off-line. There was a heterogeneity in DMI parameters between different myocardial walls and a gradient was found between basal and mid segments. Both persisted during exercise. Group I had significantly higher TPV than groups II and III. Increase in workload was accompanied by an increase in velocities, while TPV decreased. Differences between groups persisted throughout exercise. CONCLUSIONS: Off-line measurements of DMI parameters are feasible during exercise. SV and E decline as age increases while A increases. SV already increases at low charge exercise and may serve as a quantitative marker for the detection of myocardial viability. Change of the absolute DMI velocity values during exercise may provide a better indicator of ischaemia or viability than the absolute values themselves.