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[Left ventricular hemodynamics in patients with sick sinus syndrome: analysis by 99mTc-RBC cardiac pool scintigraphy
K Matsumura1, E Nakase, A Hasegawa
1Department of Internal Medicine, Kyoto Minami Hospital.
Insights
Sick sinus syndrome impairs left ventricular (LV) systolic and diastolic functions. These cardiac function deficits persist even with artificial pacing, suggesting underlying pathophysiology possibly linked to vasospastic angina.
Area of Science:
- Cardiology
- Nuclear Medicine
Background:
- Sick sinus syndrome (SSS) can affect cardiac function.
- Left ventricular (LV) performance in SSS patients requires further investigation.
Purpose of the Study:
- To analyze LV systolic and diastolic functions in SSS patients.
- To compare cardiac function between SSS patients and healthy controls.
Main Methods:
- Utilized 99mTc-RBC cardiac pool scintigraphy with forward and backward multiple gated study (FBMG).
- Analyzed LV time activity curves, including peak ejection rate (PER) and peak filling rate (PFR).
- Assessed function at rest and during A-V sequential pacing at varying rates.
Main Results:
- SSS patients exhibited significantly decreased LV PER and PFR compared to controls.
- Increased pacing rates further reduced PFR in patients with diminished PER.
- No significant organic coronary artery disease was found, but vasospastic angina was more frequent.
Conclusions:
- LV systolic and diastolic functions are impaired in SSS patients, both at rest and during pacing.
- The underlying cause of impaired LV function in SSS is unknown.
- A potential shared pathophysiology between SSS and vasospastic angina is suspected.
Abstract:
The left ventricular (LV) systolic and diastolic functions in 31 patients with sick sinus syndrome (types I and II) were analyzed using LV time activity curves obtained by a 99mTc-RBC cardiac pool scintigraphy-forward and backward multiple gated study (FBMG) and compared with those in controls. On A-V sequential pacing (rate, 70 bpm; A-V delay, 150 msec), LV-peak ejection rate (PER) and peak filling rate (PFR) were significantly decreased compared to those in normal controls. As pacing rate was increased, PFR decreased significantly in patients in whom PER was decreased. The etiology of disturbed LV systolic and diastolic functions in patients with sick sinus syndrome remains unknown. No patient had significant organic coronary artery disease or other cardiac disorder. On the other hand, the frequency of vasospastic angina was higher in this group than in the controls. We suspect that sick sinus syndrome and vasospastic angina probably share a common pathophysiology. In patients with sick sinus syndrome, LV systolic and diastolic functions are impaired at rest and during A-V sequential pacing.