297. Case Report: A Sinister Cause of Sudden Cardiac Death – University of Washington

CardioNerds (Daniel Ambinder) join Dr. Tomio Tran, Dr. Vid Yogeswaran, and Dr. Amanda Cai from the University of Washington for a break from the rain at the waterfront near Pike Place Market. They discuss the following case: A 46-year-old woman presents with cardiac arrest and was found to have cor triatriatum sinistrum (CTS). CTS is a rare congenital cardiac malformation in which the left atrium is divided by a fenestrated membrane, which can restrict blood flow and cause symptoms of congestive heart failure. Rarely, the condition can present in adulthood. To date, there have been no cases of sudden cardiac death attributed to CTS. Dr. Jill Steiner provides the E-CPR for this episode. Audio editing by CardioNerds Academy Intern, student doctor Akiva Rosenzveig. CardioNerds is collaborating with Radcliffe Cardiology and US Cardiology Review journal (USC) for a ‘call for cases’, with the intention to co-publish high impact cardiovascular case reports, subject to double-blind peer review. Case Reports that are accepted in USC journal and published as the version of record (VOR), will also be indexed in Scopus and the Directory of Open Access Journals (DOAJ). CardioNerds Case Reports PageCardioNerds Episode PageCardioNerds AcademyCardionerds Healy Honor Roll CardioNerds Journal ClubSubscribe to The Heartbeat Newsletter!Check out CardioNerds SWAG!Become a CardioNerds Patron! Case Media - A Sinister Cause of Sudden Cardiac Death – University of Washington A 40-year-old woman with a history of recurrent exertional syncope had sudden loss of consciousness while kissing her partner. The patient received bystander CPR while 911 was called. EMS arrived within 10 minutes of the call and found the patient apneic and unresponsive. Initial rhythm check showed narrow complex tachycardia at a rate of 136 BPM. ROSC was eventually achieved. A 12-lead ECG showed that the patient was in atrial fibrillation with rapid ventricular rate. The patient was intubated and brought to the emergency department. The patient spontaneously converted to sinus rhythm en route to the hospital. In the emergency department, vital signs were remarkable for hypotension (76/64 mmHg) and sinus tachycardia (110 BPM). The physical exam was remarkable for an inability to follow commands. Laboratory data was remarkable for hypokalemia (2.5 mmol/L), transaminitis (AST 138 units/L, ALT 98 units/L), acidemia (pH 7.12), and hyperlactatemia (11.2 mmol/L). CT scan of the chest revealed a thin membrane within the left atrium. Transthoracic echocardiogram showed normal biventricular size and function, severe tricuspid regurgitation, pulmonary artery systolic pressure of 93 mmHg, and the presence of a membrane within the left atrium with a mean gradient of 25 mmHg between the proximal and distal left atrial chambers. Vasopressors and targeted temperature management were initiated. The patient was able to be re-warmed with eventual discontinuation of vasopressors, however she had ongoing encephalopathy and seizures concerning for hypoxic brain injury. There was discussion with the adult congenital heart disease team about next steps in management, however the patient was too sick to undergo any definitive treatment for the intracardiac membrane within the left atrium. The patient developed ventilator associated pneumonia and antibiotics were initiated. The patient ultimately developed bradycardia and pulseless electrical activity; ROSC was unable to be achieved, resulting in death. Autopsy was remarkable for the presence of a fenestrated intracardiac membrane within the left atrium and lack of other apparent congenital heart defects. There was right ventricular hypertrophy and pulmonary artery intimal thickening with interstitial fibrosis suggestive of pulmonary hypertension. There were bilateral acute subsegmental pulmonary emboli present. The cause of death was declared to be arrhythmia in the setting of pulmonary hypertension and right sided heart failure caused by cor triatriatum sinistrum with a significant contribution from acute subsegmental pulmonary emboli. Case Media - A Sinister Cause of Sudden Cardiac Death – University of Washington Pearls - A Sinister Cause of Sudden Cardiac Death – University of Washington In a patient presenting with syncope, the following feature may indicate an underlying cardiac etiology: exertional syncope, sudden syncope without a prodrome, structural heart disease, advanced age, and family history of sudden cardiac or unexplained death. Cor triatriatum sinistrum is diagnosed by CT, echocardiography, or MRI and is often found incidentally in adults. Acute management of CTS is similar to mitral stenosis and consists of 1) careful volume management to avoid both hypovolemia and hypervolemia, and 2) avoidance of tachycardia to allow for adequate LV filling during diastole. Surgical resection of the membrane is definitive. A mean gradient of ≥ 8 mmHg across a CTS membrane is hemodynamically significant and should prompt surgical evaluation for membrane resection. Show Notes -A Sinister Cause of Sudden Cardiac Death – University of Washington SyncopeLoss of consciousness due to transient decrease in cerebral blood flowDifferentialOrthostaticNeurally mediatedCardiogenicMimickers of syncope: seizures, head trauma causing loss of consciousness, hypoglycemiaRed flag symptoms of cardiogenic syncopeAdvanced ageExertional or while lying downPalpitations prior to eventStructural heart diseaseFamily history of unexplained or sudden cardiac deathStructural heart disease etiologiesGenerally left sided and causes obstruction to blood flowValvular stenosesHypertrophic cardiomyopathyCardiac tumors Arrhythmia etiologiesCan be caused by any brady- or tachyarrhythmia, especially in the setting of structural heart disease Most commonlySinus node diseaseHigh degree heart block Ventricular arrhythmia Pulse pressureDifference between systolic and diastolic pressureNormal ~ 40 mmHgNarrow - 100 mmHgWide pulse pressure etiologiesPhysical conditioning (normal variant)Aortic regurgitationSevere iron deficiency anemiaHyperthyroidismArteriosclerosisShunting from arteriovenous fistulas Narrow pulse pressure etiologies – indicates low stroke volume/cardiac outputHeart failureHypovolemiaBlood lossValvular stenosisCardiac tamponade Pulmonary embolism Cor triatriatum sinisterPresence of a membrane within the left atrium that divides the left atrium into 2 chambersPathophysiologyTheorized to be caused by misincorporation of the pulmonary veins within the left atrium causing a membrane within the left atriumIf restrictive, sequelae include congestive heart failure, pulmonary hypertension, and right ventricular dysfunctionOften associated with other congenital heart disease (ASD, pulmonary venous return, mitral regurgitation)EpidemiologyAmong the rarest of all congenital heart disease (up to 0.4% of all congenital heart disease, but true incidence is unknown as many can be asymptomatic)Found more often in infancy/childhood; often found incidentally in adultsSigns/symptomsMany are asymptomaticOver time, membrane may become fibrotic or calcified and cause significant obstructionInfants/children – pulmonary congestion, respiratory infections, cyanosis, growth restrictionAdults – dyspnea, chest pain, palpitations, syncopeThrombotic events are common likely from vascular injury and congestion/stasisAtrial arrhythmia is associated with CTS, possibly from scarring of the membrane vs chronic elevation of left atrial pressureDiagnosisMade by imaging (CT chest/cardiac, echocardiography, MRI)Primary competing differential diagnosis is supravalvular mitral ringIf intra-atrial membrane contains the left atrial appendage and pulmonary veins -> supravalvular mitral ringAssociated with Schone complex (supravalvular mitral ring, parachute mitral valve, subaortic stenosis, aortic coarctationCTS rarely associated with Shone complexIf intra-atrial membrane contains only the pulmonary veins -> CTSCan be found incidentally and cause technical issues in cardiac procedures that require transeptal atrial puncturesQuantify degree of restriction with echocardiography; gradients ≥ 8 mmHg are significant per AHA guidelines TreatmentAcute:Diuretics to treat congestionFluids to avoid hypovolemia due to preload dependence for cardiac outputTreat underlying causes of tachycardia to optimize diastolic fillingTreat tachyarrhythmia with anti-arrhythmis and AV nodal blockers Chronic/definitive: Surgical resection of the membrane offers a good and durable outcome Low recurrence rate, residual gradients likely due to incomplete resection Pulmonary hypertension WHO classificationGroup 1 – Pulmonary arterial hypertension (idiopathic, toxin induced, HIV, connective tissue disease, congenital heart diseaseCongenital heart disease comprises a small portion of group 1, typically from shunt lesionsGroup 2 – Left sided heart diseaseGroup 3 – Pulmonary diseaseGroup 4 – CTEPH Group 5 – Unclear mechanisms (sickle cell, sarcoid, metabolic disease) References - Albassam OT, Redelmeier RJ, Shadowitz S, Husain AM, Simel D, Etchells EE. Did This Patient Have Cardiac Syncope?: The Rational Clinical Examination Systematic Review. JAMA. 2019;321(24):2448-2457. doi:10.1001/jama.2019.8001 Jegier W, Gibbons JE, Wigglesworth FW. Cortriatriatum: clinical, hemodynamic and pathological studies surgical correction in early life. Pediatrics. 1963;31:255-267. Jha AK, Makhija N. Cor Triatriatum: A Review. Semin Cardiothorac Vasc Anesth. 2017;21(2):178-185. doi:10.1177/1089253216680495 Rudienė V, Hjortshøj CMS, Glaveckaitė S, et al. Cor triatriatum sinistrum diagnosed in the adulthood: a systematic review. Heart. 2019;105(15):1197-1202. doi:10.1136/heartjnl-2019-314714 Saxena P, Burkhart HM,