Danni Fu
Brown University USATitle: A Young Female with Syndrome of Inappropriate Sinus Tachycardia Seeking Preconception Counseling
Abstract:
Background:
Syndrome of inappropriate sinus tachycardia (IST) is defined as resting sinus heart rate (HR) of greater than 100 with a mean 24-hour HR of greater than 90 with no underlying etiology associated with symptoms of palpitations and an EKG with no change in P-wave morphology1,3,4. Historically, it was thought to be a rare disease of young females, although recently it was shown to often happen in middle-aged patients without a gender preference3. Its effects and management during pregnancy is not well understood.
Objective:
We demonstrate a classic case of IST in a young female who is now coming in for preconception counseling.
Case/Result:
22-year-old female was diagnosed with IST after she presented with palpitations and lightheadedness and found to have resting HR in the 160s and EKG that showed sinus tachycardia with consistent P-wave morphology. Work-up including complete blood count, complete metabolic panel, urine pregnancy test, urine toxicology, thyroid function test, am cortisol, plasma metanephrines, 24-hour urine metanephrines, CT pulmonary embolism, and echocardiogram were unremarkable. She was started on diltiazem with improvement. She was doing well for 2 years until she came in for preconception counseling regarding the risks of her disease.
Discussion/Conclusion:
The etiology of IST is not well understood2,4; recent study suggests that some IST patients have anti-β adrenergic receptor (AR) antibodies that stimulate the corresponding membrane receptor to result in an increase of cAMP without desensitization2 leading to prolonged stimulation of sinus node β ARs and persistent sympathetic activity2. IST can present as heart failure in pregnancy refractory to beta-blockers and nondihydropyridine calcium channel blockers5. Although it is not recommended in non-pregnant patients given its risk of complications4, ablation is often the next step for drug-resistant IST5. Ivabradine, an If channel inhibitor, has been shown to have greater efficacy in drug resistant IST1, although its effects in pregnancy is unknown. Prior case studies have shown that ivabradine was effective in treating IST related cardiomyopathy with minimal maternal and fetal side effects5.
Keywords: inappropriate sinus tachycardia, preconception, pregnancy
Biography:
Danni Fu, MD is an internal medicine specialist in Manhasset, NY
Danni Fu
Brown University USATitle: A Novel Thrombolytic Protocol for Mechanical Aortic Valve Thrombosis
Abstract:
Introduction:
Subtherapeutic anticoagulation (AC) of mechanical aortic valves (MAV) can lead to thrombosis causing obstruction. Hyperdynamic left ventricular (LV) systolic function, elevated LV outflow tract velocity, and aortic insufficiency (AI) can be seen on echocardiogram (TTE) due to changes in transvalvular gradient. Thrombolytics (tPA) are used in high-risk candidates while surgery is done in low/moderate risk candidates and those with large clots. Our case shows a high-risk candidate treated with a novel tPA protocol that resulted in the resolution of aortic valve obstruction.
Case Description:
54 yo female with MAV underwent abdominal surgery where AC was held now presenting with cardiogenic shock. TTE showed new severe aortic stenosis (AS) due to leaflet restriction from a large thrombus along with new AI, which precluded mechanical circulatory support. She was a poor surgical candidate and was given 50mg of alteplase at a rate of 8.3 mg/dl along with low intensity IV heparin. After 2 hours, TTE showed resolution of AI and significant improvement of AS. Unfortunately she experienced cardiac arrest due to other reasons and failed to respond to multiple rounds of resuscitation. Hemoglobin checked during the code blue was stable, ruling out hemorrhage as the cause of death.
Discussion:
tPA infusion for AV thrombosis is generally recommended at an ultraslow rate of 25mg over 25 hours followed by IV heparin 6 hours post infusion. Given the instability of our patient, we administered 50mg of tPA over 6 hours, simultaneously with heparin, which led to the resolution of AI and improved transvalvular gradients. Observational studies indicate lower complication rates with the ultraslow protocol, but it can fail in those with severe symptoms or larger thrombus burden. Our case demonstrates a new protocol that can be considered in patients with hemodynamically unstable AV thrombosis.
Keywords: Aortic valve thrombosis, mechanical valve, thrombolysis
Biography:
Danni Fu, MD is an internal medicine specialist in Manhasset, NY