Biomedical subjects

Robert Hong

Publications and source records attributed to Robert Hong.

4 recordsLinked to original sources

PubMed2006

Tachycardia-induced elevations in cardiac troponin in the absence of coronary artery disease.

Elevations in serum cardiac troponins are used to diagnose myocardial infarction caused by ischemic heart disease. Several other conditions result in elevated cardiac makers in the absence of significant coronary artery disease. While not commonly recognized elevations of troponin I (TNI) may be seen in patients with protracted arrhythmias. We describe three patients with prolonged tachycardia, heart rates of 200-260 beats per minute, who had elevated TNI (0.81-4.6 ng/ml) but no significant coronary artery disease. Two patients presented with ventricular tachycardia and one had an atrioventricular re-entrant tachycardia. None of the patients presented with symptomatic hypotension. Coronary angiography in all three patients did not demonstrate significant coronary artery disease. The finding of an elevated TNI level may be the result of tachycardia and not myocardial infarction related to ischemic heart disease.

Administration, Oral↗

PubMed2004

Atrio-esophageal fistula as a complication of percutaneous transcatheter ablation of atrial fibrillation.

BACKGROUND: Radiofrequency ablation for atrial fibrillation is becoming widely practiced. METHODS AND RESULTS: Two patients undergoing circumferential pulmonary vein ablation for atrial fibrillation in different centers developed symptoms compatible with endocarditis 3 to 5 days after the procedure. Their clinical condition deteriorated rapidly, and both suffered multiple gaseous and/or septic embolic events causing cerebral and myocardial damage. One patient survived after emergency cardiac and esophageal surgery; the other died of extensive systemic embolization. An atrio-esophageal fistula was identified in both patients. CONCLUSIONS: Atrio-esophageal fistulas can occur after catheter ablation in the posterior wall of the left atrium. This diagnosis should be excluded in any patient with symptoms or signs of endocarditis after left atrial ablation, and expeditious cardiac surgery is critical if the diagnosis is confirmed. Lower power and temperature settings for applications of radiofrequency energy along the posterior left atrial wall may prevent further cases of fistula formation.

Adult↗

PubMed2004

The successful treatment of end stage of heart failure associated with complete right bundle branch block with biventricular pacemaker placement.

Biventricular pacing has been used to treat patients with symptomatic heart failure, systolic left ventricular dysfunction and intraventricular conduction delays. This modality is usually reserved for the treatment of patients with a left bundle branch block pattern on electrocardiogram. We report the successful use of biventricular pacing in a patient with heart failure and a right bundle branch block conduction delay.

Adult↗

PubMed2003

Signal coding in cochlear implants: exploiting stochastic effects of electrical stimulation.

Speech perception in quiet with cochlear implants has increased substantially over the past 17 years. If current trends continue, average monosyllabic word scores will be nearly 80% by 2010. These improvements are due to enhancements in speech processing strategies, to the implantation of patients with more residual hearing and shorter durations of deafness, and to unknown causes. Despite these improvements, speech perception in noise and music perception are still poor in most implant patients. These deficits may be partly due to poor representation of temporal fine structure by current speech processing strategies. It may be possible to improve both this representation and the dynamic range of electrical stimulation through the exploitation of stochastic effects produced by high-rate (eg, 5-kilopulse-per-second) pulse trains. Both the loudness growth and the dynamic range of low-frequency sinusoids have been enhanced via this technique. A laboratory speech processor using this strategy is under development. Although the clinical programming for such an algorithm is likely to be complex, some guidelines for the psychophysical and electrophysiological techniques necessary can be described now.

Cochlear Implants↗