- Email: [email protected]
Physical activity influences heart rate variability and very-low-frequency components in Holter electrocardiograms
IN
CONSULTATION
resistance for the epoprostenol and control groups were - 2 1 percent and +9 percent, respectively (difference in mean change, - 4 . 9 mm Hg per liter per minute; 95 percent confidence interval, - 7 . 6 to - 2 . 3 mm Hg per liter per minute; P < 0.001). Eight patients died during the study, all of whom had been randomly assigned to conventional therapy (P = 0.003). Serious complications included four episodes of catheter-related sepsis and one thrombotic event. Conclusions: As compared with conventional therapy, the continuous intravenous infusion of epoprostenol produced symptomatic and hemodynamic improvement, as well as improved survival in patients with severe primary pulmonary hypertension.
opment of primary pulmonary hypertension. Active surveillance for this disease should be considered, particularly since the use of anorexic drugs is expected to increase in the near future.
Renal Insufficiency: Gadopentetate Dimeglumine as a Radiographic Contrast Agent During Peripheral Vascular Interventional Procedures J~ Raufman,S.C Geller,A.C.Wal~an. Depa~nentof Radiology,Hamrd Medical SchoolMassachusettsGeneralHospit~,Boston,H~ Radiology1996;198:579-81. Gadopentetate dimeglumine diluted 1:1 with 0.9% normal saline was used as the radiographic contrast agent in two patients with azotemia who underwent peripheral vascular interventional procedures. The patients had no evidence of contrast material-induced renal failure after the procedures. The radiographic attenuation of the diluted gadopentetate dimeglumine was equivalent to diatrizoate meglumine diluted to 40 mg iodine per milliliter. Gadopentetate dimeglumine is an alternative radiographic contrast material for azotemic patients.
Physical Activity Influences Heart Rate Variability and Very-Low-Frequency Components in Holter Electrocardiograms L Bemardi,F. Valle,M. Coco,A. Cakiati,P. Sleight.Dipammentodi Medicina Intema, Sezioneainica HedicaI, Universityof Pavia,Pavia,Italy.CardiovascRes 1996;32:234-7. Objective: A major proportion of RR interval variability in long-term recordings is due to slow (<0.03 Hz) fluctuations, which seem to be a good predictor of survival after myocardial infarction, whose origin remains unclear. Methods: To study the effect of physical activity we compared by spectral analysis of the RR interval in 10 healthy human subjects (aged 28 [s.e. 21 years) during 1-h periods each of rest (no activity), alternating rest and mild exercise (rhythmic acti~qty), and normal spontaneous (random) actixqty. Resuits: Compared to rest, during both random and rh}¢hmic actix4ties, the RR variance increased significantly (from 5802 I10301 to 13388 [1448] ms ~, P < 0.05, and to 24959 [2901], P < 0.00l) due to an increase in power below 0.03 t-tz (from 3017 [467] to 9606 [966] ms 2, P < 0.01, and to 21103 [2298] ms 2, P < 0.001) which explained 55.4, 73.2 and 86.1% of total RR variance, respectively. Conclusions: The amount of RR variability and its slower fluctuations largely depend on physical activity, regardless of its regular or irregular occurrence. Attempts to predict cardiovascular prognosis on the basis of RR fluctuations should therefore take account of the confounding effect of physical activity since healthier subjects would probably be more active.
A Comparison of Continuous Intravenous Epoprostenol (Prostacyclin) With Conventional Therapy for Primary Pulmonary Hypertension Iq. B~t, LJ. Rubin,W~ tong, M.D. HcGoon,S. Rich,D.B. Badesch,B.M.Groves, V.F. Tapson,E.C Bourge,B.H. Brundage,S.ICKoerner,D. Langleben,C~ Keller,S. Murali,B.F. Uretsky,LM. aayton, M.H.Jobsis,S.D.Blackburn,Jr. et al. Department of Pediamcs,ColumbiaUniversity,Collegeof Physiciansand Surgeons,New York,NY. N EngtJ Hed 1996;334:296-301. Background: Primary pulmonary hypertension is a progressive disease for which no treatment has been shown in a prospective, randomized trial to improve survival. Methods: We conducted a 12-week prospective, randomized, multicenter open trial comparing the effects of the continuous intravenous infusion of epoprostenol (formerly called prostacyclin) plus conventional therapy with those of conventional therapy alone in 81 patients with severe primary" pulmonary hypertension (New York Heart Association functional class lII or IV). Results: Exercise capacity was improved in the 41 patients treated with epoprostenol (median distance walked in six minutes, 362 m at 12 weeks vs. 315 m at base line), but it decreased in the 40 patients treated with conventional therapy alone (204 m at 12 weeks vs. 270 m at base line; P < 0.002 for the comparison of the treatment groups). Indexes of the quality of life were improved only in the epoprostenol group (P < 0.01). Hemodynamics improved at 12 weeks in the epoprostenol-treated patients. The changes in mean pulmonary-artery pressure for the epoprostenol and control groups were - 8 percent and +3 percent, respectively (difference in mean change, - 6 . 7 mm Hg; 95 percent confidence interval, - 1 0 . 7 to - 2 . 6 mm Hg; P < 0.002), and the mean changes in pulmonary vascular
Acute Effects of Ethanol Ingestion on Signal-Averaged Electrocardiograms M.A.Cardy,&L Donnerstein,LF. KeUy,N.H, Bittner,G.M.Palombo,S.].Goldberg. Dept of Pediatrics,ArizonaUniv.HealthSciencesCenter,Tucson,AZ. Am J Cardiol 1996;77:1356-7. We studied the effects of acute ingestion of ethanol on signal-averaged electrocardiograms in 10 normal subjects. Both atrial and ventricular signal-averaged electrocardiograms were prolonged after ingestion of ethanol.
ACC CURRENTJOURNAL RE\ IE\V May/June 1997
82
CONSULTATION
resistance for the epoprostenol and control groups were - 2 1 percent and +9 percent, respectively (difference in mean change, - 4 . 9 mm Hg per liter per minute; 95 percent confidence interval, - 7 . 6 to - 2 . 3 mm Hg per liter per minute; P < 0.001). Eight patients died during the study, all of whom had been randomly assigned to conventional therapy (P = 0.003). Serious complications included four episodes of catheter-related sepsis and one thrombotic event. Conclusions: As compared with conventional therapy, the continuous intravenous infusion of epoprostenol produced symptomatic and hemodynamic improvement, as well as improved survival in patients with severe primary pulmonary hypertension.
opment of primary pulmonary hypertension. Active surveillance for this disease should be considered, particularly since the use of anorexic drugs is expected to increase in the near future.
Renal Insufficiency: Gadopentetate Dimeglumine as a Radiographic Contrast Agent During Peripheral Vascular Interventional Procedures J~ Raufman,S.C Geller,A.C.Wal~an. Depa~nentof Radiology,Hamrd Medical SchoolMassachusettsGeneralHospit~,Boston,H~ Radiology1996;198:579-81. Gadopentetate dimeglumine diluted 1:1 with 0.9% normal saline was used as the radiographic contrast agent in two patients with azotemia who underwent peripheral vascular interventional procedures. The patients had no evidence of contrast material-induced renal failure after the procedures. The radiographic attenuation of the diluted gadopentetate dimeglumine was equivalent to diatrizoate meglumine diluted to 40 mg iodine per milliliter. Gadopentetate dimeglumine is an alternative radiographic contrast material for azotemic patients.
Physical Activity Influences Heart Rate Variability and Very-Low-Frequency Components in Holter Electrocardiograms L Bemardi,F. Valle,M. Coco,A. Cakiati,P. Sleight.Dipammentodi Medicina Intema, Sezioneainica HedicaI, Universityof Pavia,Pavia,Italy.CardiovascRes 1996;32:234-7. Objective: A major proportion of RR interval variability in long-term recordings is due to slow (<0.03 Hz) fluctuations, which seem to be a good predictor of survival after myocardial infarction, whose origin remains unclear. Methods: To study the effect of physical activity we compared by spectral analysis of the RR interval in 10 healthy human subjects (aged 28 [s.e. 21 years) during 1-h periods each of rest (no activity), alternating rest and mild exercise (rhythmic acti~qty), and normal spontaneous (random) actixqty. Resuits: Compared to rest, during both random and rh}¢hmic actix4ties, the RR variance increased significantly (from 5802 I10301 to 13388 [1448] ms ~, P < 0.05, and to 24959 [2901], P < 0.00l) due to an increase in power below 0.03 t-tz (from 3017 [467] to 9606 [966] ms 2, P < 0.01, and to 21103 [2298] ms 2, P < 0.001) which explained 55.4, 73.2 and 86.1% of total RR variance, respectively. Conclusions: The amount of RR variability and its slower fluctuations largely depend on physical activity, regardless of its regular or irregular occurrence. Attempts to predict cardiovascular prognosis on the basis of RR fluctuations should therefore take account of the confounding effect of physical activity since healthier subjects would probably be more active.
A Comparison of Continuous Intravenous Epoprostenol (Prostacyclin) With Conventional Therapy for Primary Pulmonary Hypertension Iq. B~t, LJ. Rubin,W~ tong, M.D. HcGoon,S. Rich,D.B. Badesch,B.M.Groves, V.F. Tapson,E.C Bourge,B.H. Brundage,S.ICKoerner,D. Langleben,C~ Keller,S. Murali,B.F. Uretsky,LM. aayton, M.H.Jobsis,S.D.Blackburn,Jr. et al. Department of Pediamcs,ColumbiaUniversity,Collegeof Physiciansand Surgeons,New York,NY. N EngtJ Hed 1996;334:296-301. Background: Primary pulmonary hypertension is a progressive disease for which no treatment has been shown in a prospective, randomized trial to improve survival. Methods: We conducted a 12-week prospective, randomized, multicenter open trial comparing the effects of the continuous intravenous infusion of epoprostenol (formerly called prostacyclin) plus conventional therapy with those of conventional therapy alone in 81 patients with severe primary" pulmonary hypertension (New York Heart Association functional class lII or IV). Results: Exercise capacity was improved in the 41 patients treated with epoprostenol (median distance walked in six minutes, 362 m at 12 weeks vs. 315 m at base line), but it decreased in the 40 patients treated with conventional therapy alone (204 m at 12 weeks vs. 270 m at base line; P < 0.002 for the comparison of the treatment groups). Indexes of the quality of life were improved only in the epoprostenol group (P < 0.01). Hemodynamics improved at 12 weeks in the epoprostenol-treated patients. The changes in mean pulmonary-artery pressure for the epoprostenol and control groups were - 8 percent and +3 percent, respectively (difference in mean change, - 6 . 7 mm Hg; 95 percent confidence interval, - 1 0 . 7 to - 2 . 6 mm Hg; P < 0.002), and the mean changes in pulmonary vascular
Acute Effects of Ethanol Ingestion on Signal-Averaged Electrocardiograms M.A.Cardy,&L Donnerstein,LF. KeUy,N.H, Bittner,G.M.Palombo,S.].Goldberg. Dept of Pediatrics,ArizonaUniv.HealthSciencesCenter,Tucson,AZ. Am J Cardiol 1996;77:1356-7. We studied the effects of acute ingestion of ethanol on signal-averaged electrocardiograms in 10 normal subjects. Both atrial and ventricular signal-averaged electrocardiograms were prolonged after ingestion of ethanol.
ACC CURRENTJOURNAL RE\ IE\V May/June 1997
82