Adrian M. Suszko

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AIMS Dispersion of repolarization (DOR) in the human heart is minimized by activation-repolarization coupling. Adrenergic stimulation can be proarrhythmic in patients with impaired left-ventricular function and its effect on repolarization dispersion has not been systematically investigated. Our objective was to study the effect of dobutamine on(More)
BACKGROUND Action potential duration alternans (APDA) can vary regionally in magnitude and phase. The influence of APDA heterogeneity on T-wave alternans (TWA) has not been defined. OBJECTIVE Our objectives were: (1) to determine how APDA affects the magnitude and spatial distribution of TWA, and (2) to optimize electrocardiographic (ECG) lead(More)
BACKGROUND Bipolar voltage mapping has a role in defining endocardial-based scar in postinfarct patients undergoing ventricular tachycardia catheter ablation. The utility of bipolar and unipolar voltages in characterizing scar has not been evaluated in patients with nonischemic cardiomyopathy. OBJECTIVE To relate left ventricular (LV) endocardial bipolar(More)
Rotors are rotating electrical waves that may sustain atrial fibrillation (AF); thereby providing therapeutic targets for catheter ablation. We propose a method for identifying rotors from circular catheter recordings of bipolar intracardiac electrograms (EGM) during AF. We use dominant frequency-based periodicity detection along with a graph search(More)
Scar delineation with late gadolinium-enhanced MRI can direct VT substrate mapping and ablation, but imaging is poor and relatively contraindicated in the majority of patients with ICDs. We present a case of scar definition using late iodine-enhanced multidetector CT in a patient with ischemic cardiomyopathy and multiple ICD shocks for VT. CT images were(More)
BACKGROUND Nonsustained ventricular tachycardia (NSVT) detected by ambulatory Holter (Holter NSVT) is a major risk factor for sudden cardiac death in hypertrophic cardiomyopathy (HCM). We hypothesized that the prognostic utility of Holter NSVT in HCM would improve with prolonged monitoring and a higher heart rate cut-off for detection. METHODS We enrolled(More)
A novel method for automatic detection of peaks corresponding to the periodic activations in complex periodic signals is proposed. The approach involves dominant frequency-based periodicity detection combined with a graph search algorithm to identify periodic activations or peaks of interest. The performance of the proposed method is demonstrated in human(More)
Biological signals, such as intracardiac electrograms during atrial fibrillation (AF), can contain multiple periodic components or peaks. We propose a method for identifying individual periodic peak trains in signals containing multiple such periodic sequences. We use dominant frequency-based periodicity detection along with a graph search algorithm to(More)
BACKGROUND The arrhythmogenic substrate in survivors of unexplained cardiac arrest (UCA) has not been defined. OBJECTIVES To test the hypothesis that patients with UCA have latent repolarization abnormalities, in particular T-wave alternans (TWA), which may be unmasked with epinephrine (EPI) challenge. METHODS We prospectively studied 10 UCA survivors(More)