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Biomedical subjects

Fred M Kusumoto

Publications and source records attributed to Fred M Kusumoto.

15 recordsLinked to original sources
PubMed2006

Implantable cardiac arrhythmia devices--part I: pacemakers.

Implantable cardiac devices have become firmly entrenched as important therapeutic tools for a variety of cardiac conditions. The first part of this two-part review will discuss the contemporary use and follow-up of pacemakers, while the second part will address the use of implantable cardioverter defibrillators and implantable loop recorders. Pacemakers are the only available treatment for symptomatic bradycardia not due to reversible causes. Large randomized studies have demonstrated a small but statistically significant reduction in atrial fibrillation associated with pacing modes that maintain atrioventricular synchrony. In contrast, pacing mode appears to have a less dramatic effect in patients with atrioventricular block. Cardiac resynchronization with specialized left ventricular leads has been shown to reduce symptoms and improve survival in patients with symptomatic heart failure, systolic dysfunction, and widened QRS complexes. For all patients, careful follow-up is necessary to ensure optimal therapeutic benefit of pacing systems.

Arrhythmias, Cardiac↗
PubMed2005

Internal atrial and ventricular defibrillation during electrophysiology procedures.

Over the last twenty years internal defibrillation has evolved from an experimental technique into an important adjunctive procedure in the electrophysiology laboratory. Internal deflbrillation is used for treating persistent atrial fibrillation and refractory ventricular arrhythmias. Atrial defibrillation can be performed with several electrode configurations but generally shocks from 1 to 50 joules are delivered between electrodes placed in the coronary sinus and lateral wall of the right atrium. Ventricular defibrillation is usually performed with electrodes in the right ventricle and superior vena cava, although "unipolar" configurations with an internal ventricular electrode and a skin electrode can be used. Currently, internal deflbrillation can be required in 5-10% of cases within the electrophysiology laboratory and will become more commonly used as electrophysiologists perform more complex catheter ablation procedures.

Atrial Fibrillation↗
PubMed2004

Doppler evaluation of the descending aorta in patients with hypertrophic cardiomyopathy: potential for assessing the functional significance of outflow tract gradients and for optimizing pacemaker function.

UNLABELLED: We evaluated whether analysis of aortic flow could be useful for determining the functional significance of left ventricular outflow gradients and for optimizing pacing therapy in patients with hypertrophic cardiomyopathy (HOCM). METHODS: Doppler echocardiography was performed in 32 patients with HOCM. Eleven patients with pacemakers (PPM) also underwent treadmill and quality-of-life (QOL) testing in a randomized crossover trial (1 month of backup pacing (AAI at 30 beats per minute), 1 month with an atrioventricular interval (AVI) of 30 ms (DDD30), and 1 month with an "optimized" AVI (DDDop) that maximized the descending aortic Doppler velocity time integral. RESULTS: Patients with HOCM displayed a notch in the aortic Doppler flow profile. The location of the notch in systole corresponded with the development of the peak left ventricular outflow gradient. Aortic flow after the notch was variable ranging from 6-48% of the total flow. In patients with pacemakers, improved response to pacing was noted in those patients that developed the notch early in systole and had subsequent attenuation of aortic flow. Optimizing the AVI was associated with improved exercise tolerance (AAI: 4.6 +/- 2.3 min., DDD30: 5.5 +/- 2.2 min., and DDDop: 7.7 +/- 2.5 min.; p < 0.05) and improved QOL. CONCLUSIONS: Patients with HOCM have a notch in their aortic Doppler flow profile. The location of the notch correlates with the development of the peak left ventricular outflow gradient and flow after the notch is variable. Patients with an early notch and attenuated flow after the notch appear to have the greatest response to pacing therapy.

Adult↗
PubMed2004

The use of the Doppler pulmonary artery velocity time integral to optimize placement of a ventricular pacing lead in a patient with Ebstein's anomaly.

Ebstein's anomaly is a rare congenital heart defect. Patients with severe symptomatic tricuspid regurgitation requiring surgical correction often have conduction system disease. We present a case of a 14 year-old girl with Ebstein's malformation and bioprosthetic tricuspid valve who required permanent pacing for symptomatic bradycardia. The placement of the right ventricular pacing lead was facilitated by the use of the Doppler pulmonary artery velocity time integral as a surrogate for stroke volume. This case demonstrates the importance of site-specific pacing and the utility of Doppler echocardiography to optimize lead placement and cardiac performance in patients with Ebstein's anomaly and advanced conduction system disease.

Adolescent↗
PubMed2003

Atrial fibrillation ablation leads to long-term improvement of quality of life and reduced utilization of healthcare resources.

In some patients, rapid activation from one or several foci can lead to atrial fibrillation. This study evaluated long-term changes in quality of life and healthcare resource utilization in patients with atrial fibrillation treated by ablation of focal triggers. Thirty-three patients underwent ablation for paroxysmal atrial fibrillation. Health surveys (SF-36) were obtained at baseline, and after 1 year and 3 years of follow-up. Health care costs were measured for the 3 years before and after ablation. Ablation was successful in 82%, partially successful in 12% (no sustained episodes but on antiarrhythmic drug therapy), and unsuccessful in 6% of patients. The average number of ablation procedures was 1.6 +/- 0.6 per patient. After ablation, patients reported significantly improved quality of life in all SF-36 categories except bodily pain. Healthcare resource utilization was significantly reduced after ablation (Clinic visits: 7.4 +/- 2.5 per year vs. 1.1 +/- 0.6 per year, p < 0.05; Emergency room visits: 1.7 +/- 0.90 per year vs. 0.03 +/- 0.17 per year, p < 0.05; Hospitalization: 1.6 +/- 0.81 vs. 0, p < 0.05). Cost of healthcare (not including procedural costs) was significantly reduced after ablation (Pre-ablation: 1,920 +/- 889 dollars/year vs. post-ablation: 87 +/- 68 dollars/year; p < 0.01). Procedural cost of ablation was 17,173 +/- 2,466 dollars/patient. Ablation of focal triggers of atrial fibrillation is associated with a sustained improvement in quality of life. Although the initial cost of ablation is high, after ablation, utilization of healthcare resources is significantly reduced.

Adolescent↗
PubMed2003

Use of intracardiac echocardiography in guiding radiofrequency catheter ablation of atrial tachycardia in a patient after the senning operation.

A patient with D-transposition of the great arteries developed drug refractory atrial tachycardia 12 years after a Senning operation. Electrophysiological study confirmed the presence of atrial baffle-tricuspid valve isthmus dependent reentrant intraatrial tachycardia. Intracardiac echocardiography facilitated initial identification of structures, catheter positioning, and identification of the atrial baffle-tricuspid valve isthmus.

Adolescent↗
PubMed2002

Radiofrequency catheter ablation of atypical atrial flutter masquerading as atrial fibrillation.

A patient with a surgically repaired double outlet right ventricle developed AF 6 months after successful RF catheter ablation of typical atrial flutter. Guided by a 64-electrode basket catheter, the patient's AF was found to be dependent on an atypical atrial flutter circuit rotating around the fossa ovalis. Successful RF catheter ablation was performed by creating a line of conduction block from the superior vena cava to the fossa ovalis.

Adult↗
PubMed2002

Prominent crista terminalis appearing as a right atrial mass on transthoracic echocardiogram.

The crista terminalis is a fibromuscular ridge formed by the junction of the sinus venosus and primitive right atrium. In these case reports, transthoracic echocardiography suggested the presence of a right atrial mass. However, subsequent transesophageal echocardiography revealed that the "right atrial mass" was actually a prominent crista terminalis. An understanding of the anatomy and the echocardiographic appearance of a prominent crista terminalis will minimize the misdiagnosis of this structure.

Aged↗
PubMedDate not supplied

The importance of the evolution of ST-T wave changes for differentiating acute pericarditis from myocardial ischemia.

A 28-year-old, moderately obese man with dyslipidemia (low-density lipoprotein 163 mg/dL, high-density lipoprotein 33 mg/dL), hypertension, active tobacco use (1 pack per day), and a family history for premature coronary artery disease (CAD) initially presented with burning, nonexertional chest discomfort exacerbated by deep inspiration. His initial electrocardiogram (ECG; Fig. 1A) was interpreted as pericarditis because of the diffuse mild ST-segment elevation and PR-segment depression. An echocardiogram demonstrated normal left ventricular systolic function and a trivial pericardial effusion. He was treated with nonsteroidal antiinflammatories and his symptoms resolved. Follow-up ECG performed the next morning (Fig. 1B) demonstrated sinus rhythm, persistent mild ST elevation, and biphasic T waves in leads V3-V4 as well as in leads III and aVF. Four months later, the patient returned with similar symptoms of chest discomfort and was admitted with the diagnosis of unstable angina. The admission ECG was unremarkable showing no persistent PR or ST-T abnormalities. He was ruled out for myocardial infarction by serial enzymes. An exercise myocardial perfusion imaging study was obtained. The patient exercised for 7 minutes 33 seconds on a standard Bruce protocol, obtained 9.4 METs, and reached 69% of maximum predicted heart rate. His exercise ECG revealed up to 2.5 mm of ST-segment elevation in leads V3-V5 accompanied by chest discomfort. The patient's chest pain resolved with cessation of exercise and 1 sublingual nitroglycerin. The ECG returned to baseline within 3 minutes of recovery. He was referred for coronary angiography and was found to have a proximal left anterior descending (LAD) stenosis and underwent percutaneous coronary intervention with stenting. He was discharged home on postprocedure day 3.

Acute Disease↗
PubMedDate not supplied

Pacing therapy in the elderly.

Bradycardia due to sinus node dysfunction and atrioventricular block is more commonly observed in the elderly. Aging is associated with progressive fibrosis in both the sinus node and atrioventricular conduction system (AV node, His bundle, right and left bundles). In the absence of reversible causes implantation of a permanent pacemaker is often required in the patient with symptomatic bradycardia. For elderly patients with sinus node dysfunction, pacing modes that preserve atrioventricular synchrony are associated with a reduced incidence of atrial fibrillation and improved quality of life. For patients with atrioventricular block, the importance of preserving atrioventricular synchrony in the elderly is controversial and is currently being evaluated.

Aged↗