Biomedical subjects

J Hartiala

Publications and source records attributed to J Hartiala.

At least 19 recordsLinked to original sources

PubMed2002

Population-based twin study of the effects of migration from Finland to Sweden on endothelial function and intima-media thickness.

Finnish men have higher coronary heart disease (CHD) mortality than Swedish men do. To assess the impact of migration to a country with lower CHD mortality on subclinical atherosclerosis, we measured early functional and structural atherosclerotic vascular changes in twins discordant for migration from Finland to Sweden. Conventional CHD risk factors, flow-mediated dilatation (FMD) of the brachial artery, carotid intima-media thickness, and carotid artery compliance were measured in 74 male twin pairs (20 monozygous, 54 dizygous), aged 42 to 69 years, in which co-one twin had migrated more than 20 years ago permanently to Sweden. There were no significant differences in CHD risk factors except for diastolic blood pressure and body fat percentage, which were higher in Sweden. In all subjects, mean FMD was non-significantly higher in Sweden (5.7+/-4.3% vs 4.9+/-4.2%, P=0.22), but in monozygous twins the difference in FMD was highly significant (7.2+/-4.4 vs 3.7+/-2.9%, P=0.003). There was no significant difference in intima-media thickness or carotid artery compliance between Sweden and Finland. We conclude that in Finnish monozygous twins the endothelial function is better among the twins that have migrated to a country with lower CHD prevalence.

Adult↗

PubMed2002

Effect of medroxyprogesterone on pulmonary arterial pressure, exhaled nitric oxide, ECG and arterial blood gases.

OBJECTIVES: To evaluate the effect of medroxyprogesterone acetate (MPA) therapy on pulmonary arterial pressure (PAP), exhaled nitric oxide (NO), electrocardiogram (ECG), and on arterial blood gases (ABG). DESIGN: A double-blind randomized placebo-controlled cross-over trial. SETTING: University hospital in Turku, Finland. SUBJECTS: Fourteen postmenopausal women with respiratory impairment. INTERVENTIONS: A 2-week placebo and a 2-week MPA period (60 mg day -1) followed by 6-week placebo or MPA washout periods. MAIN OUTCOME MEASURES: The systolic PAP was estimated by Doppler echocardiography. PAP, ECG, NO and ABG were monitored at baseline, after 2-week placebo and MPA periods, and after 3- and 6-week placebo and MPA washout periods. RESULTS: The mean PaCO2 at baseline was 5.4 +/- 0.6 kPa (mean +/- SD). The average decrease of PaCO2 on MPA was -0.8 +/- 0.3 kPa (P < 0.001) and 0.3 +/- 1.0 kPa (P = 0.007) at the 3-week washout. The mean systolic PAP at baseline was 44.3 +/- 14.5 mm Hg. MPA did not change PAP until the 6-week washout, when the average increase of + 6.9 +/- 19.8 mm Hg (P = 0.002) was observed. No changes occurred in PaO2, exhaled NO or the ECG axes. The PR interval was shorter only on MPA (15.9 +/- 27.0 ms, P = 0.020) whereas the QRS duration remained shorter up to 3-week washout (3.9 +/0 5.5 ms, P = 0.008 and 4.0 +/- 14.3 ms, P = 0.032). The systolic and diastolic BP and the heart rate did not change. CONCLUSIONS: Despite prolonged decrease in PaCO2, short-term MPA had no effect on exhaled NO and did not decrease systolic PAP in postmenopausal women with respiratory impairment. MPA shortened the PR interval and the QRS duration, the latter effect being sustained at least up to 3 weeks.

Aged↗

PubMed2002

Transoesophageal echocardiography in selecting patients for anticoagulation after ischaemic stroke or transient ischaemic attack.

OBJECTIVES: To investigate prospectively the role of transoesophageal echocardiography (TEE) in selecting patients for anticoagulation in an unselected stroke population. METHODS: Transthoracic echocardiography (TTE) and TEE were done in all clinically suitable hospitalised patients (n = 457) with transient ischaemic attack or ischaemic stroke in the acute phase during a two year period in Turku University Hospital. 441 patients were successfully evaluated for cardiac sources of embolism using TEE within 31 days of the event. RESULTS: A major risk factor for a cardiac source of embolism excluding atrial fibrillation, acute myocardial infarction, and prosthetic valve was detected in 10% of patients and a minor risk factor for a cardiac source of embolism in 46%. When a major risk factor of a cardiac source of embolism was detected using TTE or TEE and no contraindications were present, the patient was given anticoagulation drugs. If a minor risk factor for a cardiac source of embolism was detected, anticoagulation treatment was started after clinical assessment, if no contraindications were present. In 62 (14%) cases, the patient was given oral anticoagulation drugs or the necessity of ongoing anticoagulation treatment was confirmed on the basis of TEE. When these anticoagulation treated patients were evaluated using logistic regression analysis, they were found to have significantly more atrial fibrillation and histories of myocardial infarctions. Moreover, the patients were mainly men. When patients in sinus rhythm and without any history of cardiac disease were analysed, 8% of patients were found to have been given anticoagulation drugs on the basis of TEE data. CONCLUSION: This study suggests that TEE should be used in patients with stroke even without any clinical evidence of cardiac disease when the patients are candidates for anticoagulation.

Adult↗

PubMed2001

Reduced myocardial flow reserve relates to increased carotid intima-media thickness in healthy young men.

Increased carotid artery wall thickness and lipoprotein oxidation are key early events in atherosclerosis. To test the hypothesis that reduced myocardial flow reserve is a marker of subclinical atherosclerosis, we examined the relationships between flow reserve and carotid artery intima-media thickness (IMT) in young men free from coronary heart disease. Basal and dipyridamole stimulated coronary blood flow was measured using positron emission tomography (PET) in 55 healthy men aged 36+/-4 years. Myocardial flow reserve was calculated as the ratio of stimulated flow to basal flow. The mean carotid artery IMT was measured using high-resolution ultrasound. Oxidised LDL was measured as baseline LDL diene conjugation. Myocardial flow reserve decreased across the quartiles of increasing IMT (P=0.006), and was 5.2+/-1.9 in the lowest quartile for IMT and 3.7+/-1.2 in the highest (P=0.04, I vs. IV quartile). In univariate analysis, oxidised LDL correlated inversely with flow reserve (r=-0.35, P=0.01) and directly with IMT (r=0.51, P<0.001). The association between flow reserve and IMT remained significant (P< or =0.01) in multivariate regression model including age, blood pressure, left ventricular mass, ox-LDL, total cholesterol, HDL-cholesterol and triglycerides as covariates. These data support the concept that reduced myocardial flow reserve reflects subclinical atherosclerosis in asymptomatic subjects, and suggest that increased lipoprotein oxidation is directly related to early structural and functional atherosclerotic vascular changes.

Adult↗

PubMed2001

Coronary flow reserve: measurement with transthoracic Doppler echocardiography is reproducible and comparable with positron emission tomography.

Detection of early vascular changes indicated by lowered coronary flow reserve (CFR) would allow early treatment and prevention of atherosclerosis. The purpose of this study was to test whether it is possible to reproducibly measure CFR with transthoracic Doppler echocardiography (TTE) in healthy volunteers. We measured CFR using dipyridamole infusion in ten healthy male volunteers with two methods: TTE and positron emission tomography (PET) with oxygen-15-labelled water (group A). However, CFR was assessed twice with TTE in eight healthy male volunteers (group B) to study the reproducibility of this method. We compared CFRs obtained using TTE flow measurements in the left anterior descending coronary artery (LAD) and PET flow measurements in the corresponding myocardial area. Coronary flow in LAD could be measured in all subjects using TTE. By TTE, an average CFR based on peak diastolic flow velocity (PDV) was 2.72 +/- 1.16, mean diastolic flow velocity (MDV) 2.56 +/- 1.06 and velocity time integral (VTI) 1.87 +/- 0.49. The results were reproducible in two repeated TTE studies (coefficient of variation in MDV 6.1 +/- 4.3%, n=8). By PET, CFR was 2.52 +/- 0.84. CFR assessed by TTE correlated closely with that measured by PET (MDV r=0.942, P<0.001; PDV r=0.912, P<0.002 and VTI r=0.888, P<0.006) and intraclass correlation was 0.929 (MDV) and tolerance limits for differences of CFRs was -0.78 to 0.72. We show that CFR measured by TTE has an excellent correlation with CFR measured by PET. We also found that TTE measurements of CFR were highly reproducible.

Adolescent↗

PubMed2001

Long-term reproducibility of ambulatory blood pressure in unselected elderly subjects.

The aim of this study was to evaluate the long-term reproducibility and validity of 24-h ambulatory blood pressure measurements (ABPM) in an unselected elderly population. In a rural Finnish community 503 randomly chosen invited persons over 65 years of age participated and went through 24-h ABPM. As part of the validation of the methodology, the reproducibility study was conducted in 26 persons (age 65-76 years). Two identical sets of measurement were performed at 4-12 (median 8) month intervals. The agreement between measurements was assessed by correlation coefficients and standard deviation (SD) of the differences. There were no significant differences in 24-h, daytime and night-time average diastolic blood pressure (DBP) and daytime average systolic blood pressure (SBP) between the two measurements. During the second measurement, 24-h SBP and night-time average SBP were slightly higher than those obtained by the first monitoring. Average 24-h SBP and DBP were 18 and 7 mmHg lower, respectively, than office blood pressure averages. The correlation coefficients were significantly higher for 24-h ambulatory blood pressure than for office blood pressure. The SD of the mean difference between visits was significantly lower for 24-h ambulatory blood pressure than for office blood pressure measurements. These findings show that the long-term reproducibility of ambulatory blood pressure is good in an elderly unselected population and better than the office blood pressure reproducibility.

Age Factors↗

PubMed2001

Transthoracic color Doppler echocardiography: a new way to diagnose coronary artery disease.

Until now, transthoracic echocardiography (TTE) has had the capability to visualize only the proximal portions of the main coronary arteries. However, we noticed that transthoracic color Doppler echocardiography has marked potential to visualize flow in the coronary arteries. In clinical cases we tested whether this method is useful for visualizing stenoses and flow even in peripheral branches of the coronaries. This article presents two illustrative clinical cases. In our experience, transthoracic color Doppler echocardiography is very suitable for clinical use.

Adult↗

PubMed2000

Epidural infusion of bupivacaine and fentanyl reduces perioperative myocardial ischaemia in elderly patients with hip fracture--a randomized controlled trial.

BACKGROUND: Perioperative myocardial ischaemia is an important risk factor for cardiac morbidity and mortality after noncardiac surgery. The impact of analgesic management on the incidence and severity of cardiac ischemia was studied in 77 elderly patients undergoing surgical treatment of traumatic hip fracture. METHODS: After hospital admission and written consent, patients were randomised to conventional analgesic regimen (intramuscular oxycodone, OPI group) or continuous epidural infusion of bupivacaine/fentanyl (EPI group). The analgesic regimens were started preoperatively. Patients were operated under spinal anaesthesia and the treatments were continued three days postoperatively. ECG was continuously recorded. ST segment depression of > or = 0.1 mV or elevation of > or = 0.2 mV lasting > or = 1 min were considered as ischaemic episodes. Nocturnal arterial oxygen saturation (SaO2) was recorded perioperatively, and subjective pain was assessed every morning using a visual analogue scale (VAS). RESULTS: Fifty-nine (OPI 30, EPI 29) patients were evaluable for efficacy. Thirteen patients (43%) in the OPI and 12 patients (41%) in the EPI group had ischaemic episodes (NS). However, significantly more patients in the OPI group had ischaemic episodes during the surgery (8 vs. 0 in the EPI group, P=0.005). The median (quartal deviation) total ischaemic burden (i.e. integral of ST-change vs. time) in patients with ischaemic episodes was ten times larger in the OPI group (340 [342] mm x min) compared with the EPI group (30 [36] mm x min) (P=0.002). There were no significant differences between the groups in average heart rates or in heart rates at the start of ischaemic episodes or in maximal heart rates during the attacks. Average nocturnal SaO2 was similar in the two groups and there were no differences in the number of hypoxaemic (SaO2<90%) episodes. Preoperatively there were no differences in subjective pain, but postoperative and average perioperative VAS scores for pain were almost 40% lower in the EPI group (P=0.006). Perioperative myocardial infarctions were not detected. CONCLUSIONS: Continuous epidural bupivacaine/fentanyl analgesic regimen, started preoperatively, reduces the amount of myocardial ischaemia in elderly patients with hip fracture.

Aged↗

PubMed1999

Reduced myocardial flow reserve does not impair exercise capacity in asymptomatic men.

We examined whether impaired coronary flow reserve in healthy men is associated with changes in cardiac performance and exercise-induced ischemia. A comparison between 7 asymptomatic men with low flow reserve (<3.5) and 8 men with normal flow reserve (>3.5) showed no differences in these parameters, suggesting that the mechanisms that control myocardial blood flow during exercise remain normal despite the alterations in the mechanisms that control the vasodilatory reaction to dipyridamole.

Adult↗

PubMed1999

Is routine echocardiography useful in patients hospitalized for chest pain? Evidence of areal myocardial dysfunction detected only by echocardiography.

To assess the diagnostic value of routine two-dimensional echocardiography in the coronary care unit setting, we studied 81 unselected patients admitted for acute chest pain. Using electrocardiography (ECG), clinical history and serum markers of myocardial injury, the patients were retrospectively diagnosed as having had definite acute myocardial infarction (AMI) with (n=13) or without (n=31) previous infarction, possible AMI with (n=14) or without (n=15) previous infarction, and non-coronary cardiac or other causes of chest pain (n=8). Abnormal wall motion was observed in 75/77 patients with a cardiac origin of symptoms (sensitivity 97%), and there were no false-positive wall motion findings. In the 73 patients who were finally diagnosed with coronary artery disease (CAD), echocardiography showed wall motion abnormality in at least one additional coronary territory area in which there were no diagnostic ECG changes for 56% of patients with CAD (41/73) (P<0. 001). These areas were considered to be indicative of the presence of myocardium at risk for future cardiac events. We conclude that in addition to being a sensitive and accurate tool for detection of ischaemic wall motion abnormalities, two-dimensional echocardiography can give valuable information about the area of myocardium at risk. Therefore, therapeutic decisions can be affected by the findings of the routine echocardiographic examination, which is recommended even in unselected coronary care unit patients.

Adult↗

PubMed1999

Genomewide scan for familial combined hyperlipidemia genes in finnish families, suggesting multiple susceptibility loci influencing triglyceride, cholesterol, and apolipoprotein B levels.

Familial combined hyperlipidemia (FCHL) is a common dyslipidemia predisposing to premature coronary heart disease (CHD). The disease is characterized by increased levels of serum total cholesterol (TC), triglycerides (TGs), or both. We recently localized the first locus for FCHL, on chromosome 1q21-q23. In the present study, a genomewide screen for additional FCHL loci was performed. In stage 1, we genotyped 368 polymorphic markers in 35 carefully characterized Finnish FCHL families. We identified six chromosomal regions with markers showing LOD score (Z) values >1.0, by using a dominant mode of inheritance for the FCHL trait. In addition, two more regions emerged showing Z>2.0 with a TG trait. In stage 2, we genotyped 26 more markers and seven additional FCHL families for these interesting regions. Two chromosomal regions revealed Z>2.0 in the linkage analysis: 10p11.2, Z=3.20 (theta=.00), with the TG trait; and 21q21, Z=2.24 (theta=.10), with the apoB trait. Furthermore, two more chromosomal regions produced Z>2.0 in the affected-sib-pair analysis: 10q11.2-10qter produced Z=2.59 with the TC trait and Z=2.29 with FCHL, and 2q31 produced Z=2.25 with the TG trait. Our results suggest additional putative loci influencing FCHL in Finnish families, some potentially affecting TG levels and some potentially affecting TC or apoB levels.

Adult↗

PubMed1998

Role of echocardiography in systemic arterial embolism. A review with recommendations.

The ability of echocardiography to diagnose sources of embolism and the role of the examination in the prediction of thromboembolism are reviewed. In addition, the yield of transthoracic (TTE) and transoesophageal echocardiography (TEE) is analysed in patients with suspected embolism and guidelines are proposed for performing echocardiography in this setting. In general, echocardiography is reliable for diagnosing sources of embolism and this applies in particular to TEE in the case of atrial, valvular, and aortic abnormalities. However, the method is useful for predicting embolism in a few cases only. There is a substantial risk in the event of mobile or protruding thrombi, but screening for these and other markers of thromboembolism seems to be unproductive in most groups of risk patients. Yet, in the presence of atrial fibrillation, echocardiography may be helpful in defining patients with an otherwise normal heart and low risk of embolism--and in defining the relatively rare patient with a clinically low-risk profile but moderate-to-severe left ventricular systolic dysfunction and a high risk of embolism. TEE-guided conversion of atrial fibrillation without weeks of preceding anticoagulation may prove useful, after further investigation. The risk of embolism in relation to the size and mobility of valvular vegetations has remained controversial. In patients with suspected recent embolism, TTE results in less than 5% new therapeutic consequences. In those with a normal TTE, the yield of TEE seems to be equally low. We therefore recommend a selective strategy: TTE and TEE can be omitted when a cardiac source of embolism appears from the clinical setting and in most patients with an obvious predisposition to cerebrovascular disease. However, in the latter cases TTE should be performed if indicated by the clinical situation, e.g. in the presence of fever and murmur. TTE is also recommended when there are no obvious markers of primary vascular disease. To preclude very rare sources of embolism (e.g. atrial thrombi despite sinus rhythm), supplementary TEE is recommended in younger patients in whom primary vascular disease is very unlikely. The diagnosis by TEE of common conditions such as atrial septal aneurysms and patent foramen ovale cannot, however, be taken as proof of the mechanism of a systemic arterial occlusive event; thus it is difficult to change therapy on the basis of such diagnoses.

Algorithms↗

PubMed1997

Circadian rhythm of frequency-domain measures of heart rate variability in pregnancy.

OBJECTIVE: To examine frequency domain measures of heart rate variability and their circadian rhythms in pregnancy. DESIGN: A longitudinal study. SETTING: University hospital in Turku, Finland. PARTICIPANTS: Sixteen healthy women between 11 and 27 weeks of pregnancy; 12 women before pregnancy; and four women postpartum. MAIN OUTCOME MEASURES: Heart rate variability as measured in frequency domain from 24-hour ambulatory electrocardiography. RESULTS: Pregnancy was associated with a lower standard deviation of R-R intervals (P < 0.01), with reduced very low (P < 0.05), low (P < 0.01), and high frequency (P < 0.05) power spectral components of heart rate variability. The high frequency power was lower at night in pregnancy, but similar in the daytime in pregnant and nonpregnant women. CONCLUSIONS: Pregnancy is associated with an overall reduction in heart rate variability, most markedly reflected in the low frequency component. This suggests altered baroreflex or sympathetic modulation of heart rate, and decreased vagal activation at night.

Adult↗

PubMed1996

Glucose uptake in the chronically dysfunctional but viable myocardium.

BACKGROUND: The regulation of glucose uptake in the dysfunctional but viable myocardium has not been studied previously in humans. METHODS AND RESULTS: Seven patients with an occluded major coronary artery but no previous infarction were studied twice with 2-[(18)F]fluoro-2-deoxy-D-glucose positron emission tomography, once in the fasting state and once during hyperinsulinemic euglycemic clamping. Myocardial blood flow was measured with [(15)O]H2O. The myocardial region beyond an occluded artery that showed stable wall-motion abnormality represented chronically dysfunctional but viable tissue. Six of the patients were later revascularized, and wall-motion recovery was detected in the corresponding regions, which confirmed viability. A slightly reduced myocardial blood flow was detected in the dysfunctional than in the remote myocardial regions (0.81 +/- 0.27 versus 1.02 +/- 0.23 mL x g(-1) x min(-1),P=.036). In the fasting state, glucose uptake was slightly increased in the dysfunctional regions compared with normal myocardium (15 +/- 10 versus 11 +/- 10 micromol/100 g per minute, P=.038). During insulin clamping, a striking increase in glucose uptake by insulin was obtained in both the dysfunctional and the normal regions (72 +/- 22 and 79 +/- 21 micromol/100 g per minute, respectively; P<.001, fasting versus clamping). CONCLUSIONS: Contrary to previous suggestions, glucose uptake can be increased strikingly by insulin in chronically dysfunctional but viable myocardium. This demonstrates that insulin control over glucose uptake is preserved in the dysfunctional myocardium and provides a rational basis for metabolic intervention.

Aged↗

PubMed1996

Exercise echocardiography in the diagnosis of coronary artery disease.

The purpose of this study was to test the applicability of exercise echocardiography in the diagnosis of coronary artery disease. The results were compared to findings of coronary angiography. 118 patients, 100 males and 18 females, who were all referred to coronary angiography for suspected ischaemic heart disease, underwent exercise echocardiography using a cycle ergometer. At coronary angiography 108 patients had significant stenosis in at least one coronary artery. Ten patients had angiographically normal coronary arteries. A new or increased wall motion abnormality detected by echocardiography after the exercise was considered an ischaemic response. Of the 108 patients with coronary artery disease, 101 had abnormal exercise echocardiograms, and the overall sensitivity of exercise echocardiography in detecting ischaemic heart disease was 94%. Among the 10 patients without coronary artery disease, seven had normal and three had abnormal exercise echocardiograms, and the specificity of the test was 70%. In conclusion, exercise echocardiography is a reliable diagnostic method in screening of ischaemic heart disease, and it can be combined relatively easily with the exercise examinations.

Adult↗

PubMed1996

Cardiac status and cardiovascular risk factors among Finnish sea pilots.

Sea pilots have been reported to form an occupational population with high risk for coronary artery diseases. In the present study the cardiovascular risk factors were studied by laboratory and bicycle-exercise tests among 135 Finnish sea pilots above 45 years of age. The most common risk factors were: elevated blood cholesterol, low physical activity and elevated blood pressure. Most sea pilots had 2-3 separate risk factors, only three of them did not have any risk factor for coronary disease, one had as many as eight. Abnormal bicycle-exercise ECG-findings were seen in 15 pilots, four of them with suspected coronary artery disease. There were no differences in laboratory results between those with normal or abnormal exercise-ECG-findings. Sea pilots had lower blood pressure, cholesterol and HDL-cholesterol values than the male population on shore. The prevalence of risk factors among sea pilots was compared with data on risk factors among the Finnish male population of the same age group, published recently.

Blood Pressure↗

PubMed1995

Saline contrast and colour Doppler transoesophageal echocardiography in detecting a patent foramen ovale and right-to-left shunts in stroke patients.

A paradoxical embolism due to right-to-left shunt through a patent foramen ovale (PFO) can be responsible for stroke and other ischaemic cerebral events. We studied the usefulness of saline contrast transoesophageal echocardiography after the Valsalva manoeuvre in detecting PFO and right-to-left shunts in 28 adult patients without known reason for a recent stroke. The results were compared with conventional transthoracic colour Doppler and with transoesophageal colour Doppler techniques. A PFO was found in 24 patients (86%) of our selected study population, whereas in four patients no PFO was found. A PFO with left-to-right shunt could be diagnosed by transthoracic colour Doppler echocardiography in only one case. A PFO with left-to-right shunt was found by transoesophageal colour Doppler echocardiography in 17 patients (61%), but in only three of them was a right-to-left shunt detected, even after the Valsalva manoeuvre. In contrast, a PFO with right-to-left shunt could be detected in 21 patients (75%) by using saline contrast transoesophageal echocardiography with the Valsalva manoeuvre. However, the method was unable to detect three cases of PFO with only left-to-right shunt, which were detected by colour Doppler transoesophageal echocardiography. In conclusion, our results show that saline contrast transoesophageal echocardiography with the Valsalva manoeuvre greatly improves the echocardiographic detection of PFO with right-to-left shunts in stroke patients.

Adult↗

PubMed1995

Imaging of the heart by MRI and PET.

This review article describes the clinical usefulness and future potential of two new methods for the imaging of the heart, which have recently also become available outside research laboratories. These methods are magnetic resonance imaging (MRI) and positron emission tomography (PET). MRI is the most rapidly increasing imaging modality in medicine today. The moving heart forms a challenge to conventionally rather slow MRI-techniques. Techniques based on ECG-gating have been mandatory in making cardiac cine-MRI possible. Even though MRI provides accurate and quantitative information of the heart, conventional methods are time-consuming, confined to special laboratories, and rather expensive. Therefore, the clinical use of cardiac MRI is, in many laboratories, limited to cases in which echocardiography does not provide adequate information (e.g. pulmonary circulation) or when the patient is not willing to have transoesophageal echocardiography for better visibility. MRI is also used instead of or to complement invasive angiography to study large vessels, and it provides excellent information on paracardiac masses. Cardiac MRI is developing rapidly and within the next few years it is likely to have a profound impact on cardiac imaging. This is based on its noninvasive nature and on the comprehensive anatomic (including coronary arteries), functional, flow, perfusion and possibly also metabolic information it has the potential to provide in a manner not comparable to any other imaging method. PET is a nuclear medicine imaging modality that allows quantitative characterization of a variety of physiological and metabolic processes in vivo. Using positron-emitting flow tracers and analogues of metabolic substrates, regional myocardial blood flow, glucose and fatty acid metabolism and oxygen consumption can be studied noninvasively by PET in research as well as in clinical practice. For example, regional myocardial glucose utilization rates can be measured accurately by PET. This allows us to study the effects of nutritional interventions, hormonal and neural effects as well as disease processes on the glucose utilization of the human heart. PET is currently the only technique that permits noninvasive quantification of regional myocardial perfusion in absolute terms. Over the last decade, PET has also emerged as a clinically useful tool to study coronary artery disease and myocardial viability.

Heart↗