Biomedical subjects

R I Blum

Publications and source records attributed to R I Blum.

4 recordsLinked to original sources

PubMed1988

Doppler echocardiographic assessment of the effect of varying atrioventricular delay and pacemaker mode on left ventricular filling.

Pulsed Doppler echocardiography was used to study the timing and dynamics of left ventricular filling in 14 patients with permanent dual-chamber programmable pacemakers. Pacemakers were programmed to atrial sensed (VDD) mode and atrial-ventricular sequential paced mode at low (DVI-L) and high (DVI-H) heart rates, and pulsed Doppler recordings of transmitral flow were analyzed at atrioventricular delays of 50 to 300 msec in each mode. There was a significant decrease in the one-third filling fraction in both VDD and DVI-L modes and a significant increase in DVI-H modes with increasing atrioventricular delay. The ratio of early filling area to atrial filling area was significantly lower at longer atrioventricular delays in both VDD and DVI-L modes. The time from pacemaker spike to mitral valve closure was highly significantly correlated with atrioventricular delay in VDD, DVI-L, and DVI-H modes (r = -0.92, p = 0.0001; r = -0.90, p = 0.0001; and r = -0.85, p = 0.0001, respectively) as was the diastolic filling time to a lesser extent (r = -0.73, p = 0.0001; r = -0.69, p = 0.0001; r = -0.61, p = 0.0001, respectively). Events reflecting atrial systole occurred at a later time in the cardiac cycle in the atrial paced vs the atrial sensed mode. Thus changes in atrioventricular delay and pacemaker mode in this group of patients are a strong determinant of the timing and dynamics of left ventricular filling.

Aged↗

PubMed1987

Utility of ambulatory electrocardiography in detecting pacemaker dysfunction in the early postimplantation period.

The value of ambulatory electrocardiography (AECG) in detecting pacemaker dysfunction before hospital discharge was assessed in 100 patients a mean of 1.2 days after pacemaker implantation. The incidence of permanent pacemaker dysfunction detected by AECG in the early postimplantation period, the frequency that pacemaker dysfunction detected by AECG was not detected by telemetric monitoring and the frequency that results of AECG led to pacemaker reprogramming before hospital discharge were determined. AECG detected at least 1 type of pacemaker dysfunction in 35% of patients and routine telemetry identified the abnormality in only 8% (p less than 0.001). Pacemaker dysfunction occurred in 42% of patients with dual-chamber devices and 27% of those with single-chamber devices (difference not significant). In the 35 patients who had pacemaker malfunction, a total of 50 instances of pacemaker dysfunction were detected. Failure of atrial capture occurred in 2% of patients, failure of atrial sensing in 9%, failure of atrial output in 1%, failure of ventricular capture in 8%, failure of ventricular sensing in 14%, failure of ventricular output due to myopotential inhibition in 11% and pacemaker-mediated tachycardia in 5%. The results of the AECG led to a clinical intervention in 22 patients (pacemaker reprogramming in 21 patients and lead repositioning in 1 patient) in whom no pacemaker dysfunction was suspected on the basis of telemetry or clinical symptoms. In conclusion, AECG provides additional benefit beyond that of routine telemetry monitoring in identifying pacemaker dysfunction in the early period after implantation.

Aged↗

PubMed1986

Serum digoxin concentrations during ethmozine antiarrhythmic therapy.

The potential for pharmacokinetic drug interaction between ethmozine (moricizine HCl), a phenothiazine class I antiarrhythmic investigational drug, and digoxin was evaluated in 13 cardiac patients with normal renal function. Antiarrhythmic therapy was initiated in patients with potentially lethal (nonlife-threatening) ventricular arrhythmias (greater than 30 ventricular ectopic beats [VEB]/hr) who were receiving maintenance digoxin therapy for congestive heart failure and/or atrial fibrillation. Serum digoxin concentrations of patients were measured frequently by radioimmunoassay and plasma ethmozine concentrations by high-performance liquid chromatographic methods. Patients entered a short-term (4 weeks) single-blind, placebo controlled ethmozine protocol with an option to receive long-term (1 to 6 months) open-label maintenance ethmozine therapy. Ambulatory ECGs (48 hour) used to assess antiarrhythmic efficacy of ethmozine during each week of the short-term protocol showed that 77% of patients demonstrated greater than 90% mean hourly frequency suppression of all forms of ventricular ectopy. Serum digoxin concentrations during short-term ethmozine dosing showed a nonsignificant (p greater than 0.05) increase of 10% to 15% (mean 0.91 ng/ml to 1.13 ng/ml). The short-term protocol serum digoxin levels correlated closely with serum digoxin concentrations during placebo therapy (1st week, r = 0.90; 2nd week, r = 0.87). Serum digoxin concentrations were not significantly different (p greater than 0.05) from placebo values at the end of 1, 3, and 6 months of maintenance ethmozine therapy. Thus, we conclude that ethmozine administered in an antiarrhythmic efficacious dosage (10 mg/kg/day) showed no important clinical or statistically significant change in serum digoxin concentrations of cardiac patients with normal renal function.

Adult↗

PubMed1986

Cardiology office computer use: primer, pointers, pitfalls.

An office computer is a utility, like an automobile, with benefits and costs that are both direct and hidden and potential for disaster. For the cardiologist or cardiovascular surgeon, the increasing power and decreasing costs of computer hardware and the availability of software make use of an office computer system an increasingly attractive possibility. Management of office business functions is common; handling and scientific analysis of practice medical information are less common. The cardiologist can also access national medical information systems for literature searches and for interactive further education. Selection and testing of programs and the entire computer system before purchase of computer hardware will reduce the chances of disappointment or serious problems. Personnel pretraining and planning for office information flow and medical information security are necessary. Some cardiologists design their own office systems, buy hardware and software as needed, write programs for themselves and carry out the implementation themselves. For most cardiologists, the better course will be to take advantage of the professional experience of expert advisors. This article provides a starting point from which the practicing cardiologist can approach considering, specifying or implementing an office computer system for business functions and for scientific analysis of practice results.

Cardiology↗