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 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)
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 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 In patients with severe left ventricular (LV) dysfunction, visible pulsus alternans coincides with visible T-wave alternans (TWA), but a similar relationship has not been described for nonvisible microscopic systolic pressure alternans (MSPA) and microvolt TWA (MTWA). OBJECTIVE The purpose of this study was to determine the prevalence of MSPA(More)
BACKGROUND Cardiomyopathy patients are at risk of sudden death, typically from scar-related abnormalities of electrical activation that promote ventricular tachyarrhythmias. Abnormal intra-QRS peaks may provide a measure of altered activation. We hypothesized that quantification of such QRS peaks (QRSp) in high-resolution ECGs would predict arrhythmic(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)