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[Dynamic left ventricular obstruction increased by nitroglycerin in elderly patients with hypertension and concentric
Insights
Nitroglycerin (NTG) significantly increased left ventricular outflow tract (LVOT) obstruction in elderly patients with hypertensive cardiomyopathy. This study highlights NTG
Area of Science:
- Cardiology
- Cardiovascular Imaging
- Pharmacology
Context:
- Elderly patients with concentric hypertrophic hypertensive cardiomyopathy (HHCM) can exhibit left ventricular outflow tract (LVOT) obstruction.
- This obstruction occurs without significant valvular disease or regional wall motion abnormalities.
- The role of pharmacologic agents in modulating this obstruction is not fully understood.
Purpose:
- To investigate the effect of sublingual nitroglycerin (NTG) on intraventricular obstruction in elderly patients with HHCM.
- To quantify changes in LVOT velocities and gradients before and during NTG administration using echocardiography and Doppler studies.
Summary:
- Echocardiographic and Doppler studies were performed on 20 elderly patients (mean age 78 years) with long-standing hypertension and HHCM.
- Measurements of LVOT peak velocities and gradients were taken before and during NTG administration.
- NTG induced a significant acceleration of LVOT velocities in all studied patients.
Impact:
- This research demonstrates that nitroglycerin can exacerbate LVOT obstruction in this specific patient population.
- Findings suggest a need for caution when administering NTG to elderly hypertensive patients with HHCM.
- Further investigation into the mechanisms and clinical implications of NTG-induced LVOT acceleration is warranted.
Abstract:
Left ventricular outflow tract (LVOT) obstruction has been observed in elderly patients with concentric hypertrophic hypertensive cardiomyopathy (HHCM) and no significant valvular disease or regional wall motion abnormalities. In order to determine whether nitroglycerin (NTG) can increase the intraventricular obstruction, we performed echocardiographic (echo) and doppler studies, before and during administration of sublingual NTG (0.8 mg). Twenty patients (n = 20) with long-standing hypertension (19 women and 1 man, mean age 78 +/- 8 yr, mean duration of hypertension 13 +/- 10 yrs were examined. The clinical findings in 17 patients were: angina 5 (29%), dyspnea 9 (53%), syncope or malaise 4 (23%). Electrocardiographic criteria of left ventricular hypertrophy was present in 4 patients and an increased cardio-thoracic ratio (greater than 0.5) in 9 cases. The following echo parameters were determined using M-mode echocardiograms: LV end-diastolic (LVID) and systolic diameter (LVIS), fractional shortening (FS), ventricular septum thickness (IVST), posterior wall thickness (PWT) and the ratio ISVT/PWT (less than 1.3 in all patients). LVM could be calculated in 15 patients and was corrected for body surface area (LVMI). Pulsed and continuous wave Doppler study showed a characteristic late-peaking velocity waveform. We localized the elevated velocities in the LVOT and determined before and during administration of NTG: LVOT peak velocities (V) and peak intraventricular gradients (G) using simplified Bernoulli equation. Results were as follows: [table: see text] Mild mitral regurgitation was observed in 14 patients (70%) and mitral annular calcifications in 11 (55%). Systolic function, as assessed by FS, was normal in all patients. NTG induced a significant acceleration of the LVOT velocities in all patients.(ABSTRACT TRUNCATED AT 250 WORDS)