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G Hendrix

Publications and source records attributed to G Hendrix.

10 recordsLinked to original sources
PubMed1996

Comparison of intravenous adenosine to intracoronary papaverine for calculation of pressure-derived fractional flow reserve.

For calculation of fractional flow reserve (FFR), simultaneous registration of both aortic pressure (Pa) and transstenotic distal coronary pressure (Pd) is necessary at steady-state maximum coronary hyperemia. The aim of the present study was to compare the maximum transstenotic gradient (delta Pmax) and pressure-derived myocardial fractional flow reserve (FFRmyo), observed during intravenous adenosine infusion, to delta Pmax and FFRmyo induced by intracoronary papaverine, which is considered to be the gold standard for induction of coronary hyperemia, but acts too short for steady-state hyperemic pressure recordings and is associated with QT-prolongation. In 24 patients with coronary stenoses of various degrees, Pa and Pd were measured simultaneously by the diagnostic catheter and a high fidelity 0.018" fiberoptic pressure monitoring guide wire, respectively. Excellent steady-state phasic intracoronary pressure recordings were obtained in all patients within 1 min after start of intravenous adenosine infusion at a rate of 140 micrograms/kg/min, and compared to delta Pmax obtained 30 sec after intracoronary administration of papaverine (12 mg LCA, 10 mg RCA). Delta Pmax was 24 +/- 15 mmHg during adenosine infusion and 24 +/- 15 mmHg after papaverine administration. Myocardial fractional flow reserve, calculated from these pressure recordings, was 0.75 +/- 0.16 and 0.75 +/- 0.15, respectively, with an individual difference of 0.02 +/- 0.01 between both values (r = 0.99). No important side effects by intravenous infusion of adenosine were observed. Thus intravenous adenosine infusion at a rate of 140 micrograms/kg/min is an excellent and safe alternative for induction of steady-state maximum coronary hyperemia and therefore is an ideal vasodilator for determination of fractional flow reserve based upon pressure recordings.

Adenosine↗
PubMed1982

Factors that affect the reproducibility of measurements of left ventricular function from first-pass radionuclide ventriculograms.

To examine which factors affect the reproducibility of ejection fraction (EF), pulmonary transit time (PTT) and segmental wall motion assessed from first-pass radionuclide angiograms (FPRA), 32 patients who had FPRA were randomized for site of injection of isotope (right or left arm) and projection (right or left anterior oblique [RAO or LAO]). The quality of injected bolus was measured from the full width at half maximum (FWHM) of the bolus time-activity curve in the superior vena cava. All patients had two sequential studies on each of two consecutive days, and each study was analyzed independently by two observers. For EF, inter- and intraobserver correlations ranged from 0.94-0.98. EF was higher in the RAO than the LAO projection (mean 47.4% vs 40.3%, p less than 0.001), but neither injection site nor bolus FWHM affected the results. For PTT, interobserver correlations ranged from 0.75-0.93 and intraobserver correlations from 0.61-0.85. Variability in PTT was large, and inter- and intraobserver variabilities were directly related to bolus FWHM (mean 0.60 +/- 0.21 second for interobserver differences in PTT of less than 2.0 seconds, mean 1.55 +/- 0.86 seconds for interobserver differences in PTT of greater than 2 seconds [p less than 0.005]). Differences in FWHM between sequential studies were 0.28 +/- 0.29 second when intraobserver differences in PTT were less than 2 seconds and 1.04 +/- 0.67 seconds when differences in PTT were greater than 2.0 seconds (p less than 0.005). Variations in PTT were not related to differences in projection or injection site. Wall motion was highly reproducible for both projections. In the RAO projection, one of 116 anterior segments (0.9%), one of 116 apical segments (0.9%), and four of 116 inferior segments (3%) were judged normal from one observer's images and abnormal from another. In the LAO view, discrepancies occurred in one of 126 septal segments (0.8%), two of 126 apical segments (1.6%) and four of 126 posterolateral segments (3%). This study shows that EF and wall motion are highly reproducible in any projection, but the choice of projection significantly affects the values for EF from FPRA. PTT measurements are less reliable, highly bolus dependent, and their use in clinical practice depends on quality control of the bolus of injected radionuclide.

Adult↗
PubMed1972

Venous graft surgery in treatment of coronary heart disease.

Sixty-seven patients have had aortocoronary venous graft bypass surgery by one surgeon for the relief of symptoms of severe coronary heart disease, including eight emergency operations. The overall operative, hospital, and late mortality was low in patients with favourable myocardial function and no previous myocardial infarction. There was a 7% mortality in patients with a normal preoperative chest radiogram, 8% mortality when the left ventricular end-diastolic pressure was normal preoperatively, and a 5% mortality in patients who had normal left ventricular angiograms. The overall mortality in all elective operations for cardiac pain resistant to medical treatment was 15.8%. 89% of survivors improved; 67% are pain-free. Exercise tolerance in survivors is increased by 135%, atrial pacing results are improved by 10%. Left ventricular end-diastolic pressure is unchanged. Left ventricular function on angiography is improved. The improvement in left ventricular function assessed objectively correlates positively with vein-graft patency, as does freedom from angina pectoris.

Adult↗
PubMedDate not supplied

Evaluation of 3 quality of life measurement tools in patients with chronic heart failure.

OBJECTIVE: The objectives of this study are to (1) Address issues related to selecting a quality of life (QOL) measuring tool; and (2) Present data from a pilot test comparing 3 QOL tools (Medical Outcomes Study Short Form-36 [SF-36], the Minnesota Living with Heart Failure Questionnaire [LHFQ], and a visual analogue scale). DESIGN: Descriptive comparative. SETTING: A Southern university-affiliated tertiary medical center outpatient heart failure clinic. PATIENTS: Thirty adults, randomly selected from those treated in a multidisciplinary, nurse practitioner-managed heart failure clinic. RESULTS: Significant correlations were found among the global or broader measures of QOL (visual analog scale and LHFQ Total score) and the component scores (LHFQ Emotional, LHFQ Physical, SF-36 Mental [MCS], and SF-36 Physical [PCS]), with the only exception being that of the LHFQ Total and the SF-36 PCS. Mental and physical components of QOL were not related within the SF-36 or between the SF-36 PCS and the LHFQ Emotional score. However, the emotional and physical scores were highly and significantly related within the LHFQ and between the SF-36 MCS and the LHFQ Physical score. CONCLUSIONS: The SF-36 was better able to differentiate physical and emotional aspects of QOL in this sample. The LHFQ subscales may be less useful in QOL assessment than the total score.

Adult↗
PubMedDate not supplied

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