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Increased prevalence of ventricular arrhythmias in essential hypertensives with dipyridamole-induced ischemic-like
A R Lucarini1, E Picano, M G Bongiorni
1Institute of Clinical Physiology Consiglio Nazionale delle Richerche CNR, Pisa, Italy.
Insights
Essential hypertensives with ventricular arrhythmias show increased risk. Dipyridamole testing positivity may identify these patients, aiding in risk stratification for arrhythmias.
Area of Science:
- Cardiology
- Clinical Medicine
- Hypertension Research
Background:
- Essential hypertensives face a higher risk of ventricular arrhythmias compared to normotensive individuals.
- Reduced coronary flow reserve is a potential mechanism contributing to arrhythmias in hypertensive patients.
- Dipyridamole infusion can induce ischemic-like ST segment depression in hypertensives with normal coronary arteries and reduced flow reserve.
Purpose of the Study:
- To determine if electrocardiographic positivity during dipyridamole testing can identify essential hypertensives at increased risk for ventricular dysrhythmias.
- To assess the correlation between dipyridamole test results and the presence of ventricular arrhythmias.
Main Methods:
- Fifty-one mild-to-moderate essential hypertensives underwent dipyridamole testing and 48-hour Holter monitoring.
- Dipyridamole (0.84 mg/kg over 10 min) infusion was used with 12-lead ECG and 2D echocardiography.
- Patients were off antihypertensive therapy for at least two weeks prior to testing.
Main Results:
- Electrocardiographically positive dipyridamole tests were observed in 80% of patients with Lown classes II-IV arrhythmias versus 23% in those with Lown classes 0-1 (P < 0.01).
- No significant differences were found between groups in mean blood pressure, left ventricular mass index, or ejection fraction.
- No transient systolic dysfunction was noted during dipyridamole testing.
Conclusions:
- Electrocardiographic positivity during dipyridamole testing is a significant indicator of increased risk for ventricular arrhythmias in essential hypertensives.
- This non-invasive test may help stratify risk and guide management in hypertensive patients prone to arrhythmias.
- Further research is warranted to explore the clinical implications of these findings.
Abstract:
Essential hypertensives are at greater risk for ventricular arrhythmias than normotensive controls. A reduction in coronary flow reserve may be one of the mechanisms underlying this increased prevalence of ventricular dysrhythmias in hypertensives. It has previously been shown that dipyridamole infusion may provoke ischemic-like S-T segment depression in essential hypertensives with angiographically normal coronary arteries and reduced flow reserve. The aim of the present study was to assess whether electrocardiographic positivity (S-T segment depression greater than 0.1 mV from baseline) during dipyridamole testing (12-lead electrocardiogram and two-dimensional echomonitoring, with the infusion of 0.84 mg/kg dipyridamole over 10 min) might identify hypertensives at greater risk for ventricular dysrhythmias. We therefore studied 51 mild-to-moderate essential hypertensives by dipyridamole testing and 48-h Holter monitoring. All patients were off therapy for at least 2 weeks before testing and Holter evaluation. Left ventricular mass (by Penn convention) and ejection fraction (by Teichholtz rule) were evaluated by two-dimensional echocardiography. Lown classes 0-1 were found in 31 patients (Group 1) and Lown classes II-IV in 20 (Group 2). The two groups overlapped for mean blood pressure (121 +/- 9 versus 124 +/- 8 mmHg), left ventricular mass index (120 +/- 27 versus 141 +/- 42 g/m2) and left ventricular ejection fraction (54 +/- 6 versus 52 +/- 6). An electrocardiographically-positive dipyridamole test was found in seven of Group I and 16 of Group II patients (23 versus 80%, P less than 0.01). No patient showed a transient, either regional or global, systolic dysfunction during dipyridamole testing.(ABSTRACT TRUNCATED AT 250 WORDS)