Nitrate-induced headache in patients with stable angina pectoris: Beneficial effect of starting on a low dosage

Background: Nitrates, although important for the management of angina pectoris, cause significant headache in many patients. Methods: In a randomized, double-blind, crossover study, 89 patients with stable angina pectoris were studied to compare two different dosage strategies of isosorbide-5-mononitrate (5-ISMN). Patients were randomized to either 60 mg 5-ISMN once daily (ed) for two weeks or to 30 mg 5-ISMN od for one week followed by 60 mg 5-ISMN od for one week. Then, there was a two-week placebo washout, after which the alternative treatment was given. The authors assessed the occurrence of angina pectoris and headache by diary cards while taking into account the numbers of isosorbide dinitrate sublingual puffs and paracetamole tablets required. Data were assessed for carryover and time effects. Results: The two dosage regimens were equally efficient for the relief of angina pectoris without development of tolerance. Thirty percent of the patients never experienced headache from the given dosages. In the remainder of them there was a highly significant time effect: the overall numbers of headache attacks in the first period of active treatment versus the second were 2,380 vs 1,400 (P <0.003). Yet significantly fewer patients had headache on low dosage than oil high dosage (45 vs 57, P <0.02). Conclusions: (1) Starting on a low dosage-was associated with a reduced frequency and severity of headache and did not notably influence the beneficial effect on angina pectoris. (2) One in 3 patients never experienced headache from the given dosages. (3) The overall number of headache attacks in the first period of active treatment was significantly higher than in the second period irrespective of the dosages given

Comparison of thallium scintigraphy and positron emission tomography

Assessment of tissue viability has become an important issue in recent years. Scintigraphic measurements have provided important diagnostic, therapeutic, and prognostic information in patients with myocardial dysfunction, who may improve in left ventricular function after revascularization. For detection of regional myocardial ischemia and viability, thallium 201 (Tl-201) has been the most widely used tracer in single-photon scintigraphy. However, Tl-201 scintigraphy may underestimate regional viability, especially after myocardial infarction. Positron emission tomography (PET) provides an advanced imaging technology that permits the accurate definition of regional tracer distribution. In combination with nitrogen (N-13) ammonia, PET allows for the sensitive and specific detection of coronary artery disease. Several studies indicate the superiority of this approach in comparison with standard Tl-201 tomographic (SPECT) imaging. In addition, regional blood flow can be accurately measured with N-13 ammonia PET, and this approach can be employed in conjunction with pharmacologic stress imaging to quantify regional flow reserve. In combination with metabolic markers, such as fluorine 18 (F-18) deoxyglucose, an indicator of glucose uptake, PET is capable of assessing myocardial viability. Furthermore, the PET approach may differentiate between various forms of cardiomyopathy. More studies are needed to define the cost-benefit ratio of both the Tl-201 reinjection and the PET technique for the management of patients with coronary artery disease or cardiomyopathy

Comparison of thallium scintigraphy and positron emission tomography

Assessment of tissue viability has become an important issue in recent years. Scintigraphic measurements have provided important diagnostic, therapeutic, and prognostic information in patients with myocardial dysfunction, who may improve in left ventricular function after revascularization. For detection of regional myocardial ischemia and viability, thallium 201 (Tl-201) has been the most widely used tracer in single-photon scintigraphy. However, Tl-201 scintigraphy may underestimate regional viability, especially after myocardial infarction. Positron emission tomography (PET) provides an advanced imaging technology that permits the accurate definition of regional tracer distribution. In combination with nitrogen (N-13) ammonia, PET allows for the sensitive and specific detection of coronary artery disease. Several studies indicate the superiority of this approach in comparison with standard Tl-201 tomographic (SPECT) imaging. In addition, regional blood flow can be accurately measured with N-13 ammonia PET, and this approach can be employed in conjunction with pharmacologic stress imaging to quantify regional flow reserve. In combination with metabolic markers, such as fluorine 18 (F-18) deoxyglucose, an indicator of glucose uptake, PET is capable of assessing myocardial viability. Furthermore, the PET approach may differentiate between various forms of cardiomyopathy. More studies are needed to define the cost-benefit ratio of both the Tl-201 reinjection and the PET technique for the management of patients with coronary artery disease or cardiomyopathy