Symptoms of Patients With Silent Ischemia as Detected by Thallium Stress Testing: Results

May-20-2014

Symptoms of Patients With Silent Ischemia as Detected by Thallium Stress Testing: ResultsOne hundred thirty-six patients of the cohort of 294 satisfied criteria for myocardial ischemia. Forty-three (32 percent) of those having a positive test had pains (chest, back, arm, and/or jaw), the angina group, whereas 93 (68 percent) did not have this symptom, the silent ischemia group. As shown in Table 1, groups were similar for clinical characteristics: age, gender, and coronary risk factor distribution were comparable. However, the anginal history was different for the groups. Individuals having angina on the test were more likely to have had a history of chest pain with activity (Table 2). Except for a higher average monthly use of nitroglycerin in the angina group, treatment for the two groups was similar (Table 2). Even when the use of antianginal drugs, exclusive of nitroglycerin, was considered as a single variable, no difference was evident (angina group: 81 percent vs 74 percent, p=0.42).
The thallium stress test findings are displayed in Table 3. Individuals who had silent ischemia exercised longer and reached a higher peak heart rate. Double product, however, was not different for the groups; this was related to the tendency of those with angina to have a higher peak systolic pressure, thereby offsetting the lower heart rate. Other findings, such as average ST segment depression, thallium scores, and percentages having reversible thallium perfusion defects, increased thallium lung uptake, or arrhythmias, were not different for the two groups. buy tavist online

The average scores reported on the postexercise symptom questionnaire are shown on Table 4. Except for weakness, which was scored higher in the angina group, the responses tended to be similar. Despite the expectation that those not having angina would report other symptoms more frequently, this was not evident. Indeed, the trend was contrary to this expectation. Angina group scores were as high or higher for all seven nonanginal symptoms. The average of the sum of all symptoms exclusive of the three anginal categories also tended to be higher for the angina group: 5.4 ±0.6 vs 4.2 ±0.3, p=NS.

Table 1—Clinical Characteristics

Variables Silent Ischemia Group n=93 Angina Group n=43 PValue
Age, yr 57 ±1 58±1 0.36
Gender, % male 63 65 0.85
Hypertension, % 45 62 0.08
Diabetes, % 24 21 0.66
High cholesterol, % 53 54 0.95
Smokers, % 79 70 0.64
Family history, % 38 39 0.92

Table 2—Angina Pectoris History

Variables Silent Ischemia Group n=93 Angina Group n=43 PValue
Pain past 12 mo, % 71 88 0.03
Effort pain, % 56 75 0.002
Nitroglycerin, No. mo 4±2 14±5 0.04
/9-blocker, % 30 38 0.37
Nifedipine, % 14 26 0.09
Diltiazem/verapamil, % 34 38 0.63
Long-acting nitrates, % 34 43 0.32
Aspirin, % 20 31 0.19
Antihypertensives, % 19 14 0.54
Insulin, % 5 0
Oral hypoglycemics, % 6 7 0.82

Table 3—Stress Test Findings

Variables SilentIschemiaGroupn=93 AnginaGroupn=43 PValue
Exercise time, min 7.3 ±0.2 6.3 ±0.3 0.004
Peak pressure, mm Hg 171 ±2 176 ±4 0.07
Peak rate, per min 142 ±2 134 ±3 0.02
Double product 23,386 ±451 23,737 ±743 0.34
ST depression, mm 0.52 ±0.09 0.79 ±0.14 0.11
Arrhythmias, % 23 30 0.58
Thallium score 2.0±0.1 2.2±0.1 0.25
Reversible defect, % 91 98 0.17
Increased lung uptake, % 29 24 0.53

Table 4—Symptom Score

Variables Silent Ischemia Group n=93 Angina Group n=43 PValue
Chest pains 0 1.1±0.1
Back pains 0 0.4±0.1
Jaw/arm pains 0 0.2±0.1
Breathlessness 1.5±0.1 1.5±0.1 0.93
Tiredness 1.1 ±0.1 1.4±0.2 0.18
Weakness 0.3±0.1 0.7 ±0.2 0.02
Dizziness 0.2±0.1 0.4 ±0.1 0.17
Lightheadedness 0.3±0.1 0.4±0.1 0.12
Headache 0 0.1 ±0.1
Leg discomfort 0.8±0.1 1.0 ±0.2 0.45