Diagnosing Hypertrophic Obstructive Cardiomyopathy
The patient presents with recurrent chest pain, a significant family history (suggesting a genetic component), and a key paradoxical reaction to sublingual nitroglycerin, where the pain increased in intensity. This response is crucial for diagnosis.
Understanding the Nitroglycerin Response
- Nitroglycerin's Usual Effect: Typically, sublingual nitroglycerin is used to relieve angina (chest pain) by dilating blood vessels, reducing the heart's workload (preload and afterload), and improving blood flow.
- Paradoxical Effect in HOCM: In Hypertrophic Obstructive Cardiomyopathy (HOCM), the heart muscle is abnormally thick, particularly the septum. This can obstruct blood flow leaving the left ventricle. Nitroglycerin, by decreasing preload (the amount of blood returning to the heart), can cause the left ventricular cavity to become smaller. This smaller cavity can lead to increased contact between the hypertrophied septum and the anterior mitral valve leaflet, worsening the outflow tract obstruction and thereby increasing chest pain.
Evaluating Other Options
- Chronic type A dissection of aorta: While causing chest pain, it typically presents differently and doesn't characteristically worsen with nitroglycerin in this manner.
- Degenerative mitral regurgitation: Usually causes shortness of breath or fatigue; chest pain is less typical, and nitroglycerin wouldn't cause worsening obstruction.
- Sub-acute bacterial endocarditis: Primarily an infectious process, symptoms like fever are expected, and the nitroglycerin response isn't characteristic.
Conclusion
The worsening chest pain upon administration of nitroglycerin strongly suggests a condition where reduced preload exacerbates an outflow obstruction. This is a classic presentation of Hypertrophic Obstructive Cardiomyopathy.
Important Questions from Heart Failure
High output cardiac failure is caused by which of the following diseases ?
1. Beri-beri
2. Severe anaemia
3. Thyrotoxicosis
Select the correct answer using the code given below:
- Kussmaul's sign is present in all of the following conditions, EXCEPT:
- Which of the following electro-cardio-graphic findings are manifestations of digitalis intoxication?
1. Ventricular bigeminy
2. Ventricular tachycardia
3. Atrial flutter
4. Atrial tachycardia with variable block
Select the correct answer using the code given below: - The treatment of choice for a 32 year old male patient of severe mitral stenosis (Rheumatic) with thickened and calcified valves on echocardiography is:
- A 55-year old man, non smoker presents with sudden onset of shortness of breath. On examination, pulse rate is 110/minute and B.P. 180/110 mm Hg. Patient is restless and anxious. Examination of chest shows bilateral rhonchi and crepitation. $S_3$ gallop is heard on auscultation of precordium. There is no history of chronic bronchitis. The most likely diagnosis is:
