Ashwini Davison Justin Dunn Jason Mock Deepa Rangachari May 13, 2009

Types of Trials Controlled Study - Randomize Control Trial (RCT) – type of scientific experiment most commonly used in testing the efficacy or effectiveness of healthcare services or technologies. With sufficient numbers, this ensures that both known and unknown confounding factors are evenly distributed between treatment groups. Considered the most reliable form because they eliminate spurious causality and bias. Observational Study Cohort study - group of people who share a common characteristic or experience within a defined period. Case Control - Studies used to identify factors that may contribute to a medical condition by comparing subjects who have that condition with patients who do not have the condition but are otherwise similar Case Series

Definition of Case Series Descriptive research study that tracks patients with a known exposure given similar treatment or examines their medical records for exposure and outcome. Also known as clinical series Can be retrospective or prospective Smaller number of patients than more powerful case-control or RCTs

Case Series Provide information when other types cannot or should not be undertaken Case series may be confounded by selection bias, which limits statements on the causality of correlations observed Results of case series can generate hypotheses that could be useful in designing further studies In this article the authors use a case series to ask the question what clinically (in the ED) can be used to differentiate Takotsubo cardiomyopathy versus ST- segment elevation myocardial infarction

What is Takotsubo cardiomyopathy? Also known as left ventricular apical ballooning syndrome, ampulla CM, stress CM Develop anginal symptoms and CHF in times of stress Extreme: acute pulmonary edema, cardiogenic shock

EKG & Labs ST segment and/or T wave abnormalities Similar to what’s seen in STEMI Serum markers may be elevated

Cath & ventriculogram Catheterization: abnormal LV function, but NORMAL coronary arteries DiastoleSystole

Diagnostic criteria (Mayo) 1) transient LV apical akinesis or dyskinesis 2) absence of obstructive CAD 3) new EKG abnormalities in absence of concurrent conditions

How Patients Were Selected Reviewed 12 consecutive cases of Takotsubo CM that presented to UVA 3 case excluded because of incomplete data Then took 9 consecutive cases of STEMI for comparison 18 cases total (9 TCM, 9 STEMI)—same time period Comparisons made between 2 groups

Demographic Results DescriptorTakotsuboSTEMI % that were female8944 Average age (years) % with chest pain % with dyspnea % with nausea/vomiting % with diaphoresis

EKG Comparisons EKG abnormalityTakotsuboSTEMI ST-segment elevation66.7%100% Inferior055.6 Lateral Anterior ST-segment depression33.3%77.8% Inferior Lateral Anterior033.3 T wave inversion66.7%33.3% QT prolongation451 ms433 ms

Other comparisons CXR findings were similar in both groups Initial troponin elevation similar STEMI peak troponin 7.34 vs TCM with 4.91 EF on echo—32.7% in Takotsubo, vs 25.2% in STEMI

Design Not really a case series by definition—used control group (STEMI patients) A number of case series were published prior (all with 9 or more pts), and a systematic review published in Appears to be a case series of Takotsubo compared with a case series of STEMIs.

Strengths Used consecutive patients to help reduce selection bias in both groups (though did exclude 3 from case group) All patients were (we assume) at the same institution

Weaknesses Time frame? Unclear how long to select patients; also unclear how STEMI pts selected. Too few patients—9 in each group. No distribution of values given, no hard data—only means/percentages, no medians. No p values or confidence intervals

Weaknesses 3 people eliminated in case group for “incomplete data”—contribute to selection bias? No risk factors noted in either group Unclear if any question was answered.

Conclusions Takotsubo CM often mimics ACS Anginal chest pain with acute heart failure This retrospective case series shows its difficult to distinguish the 2 in the ER

Take Home Message Physicians need to be aware of this alternative diagnosis to a STEMI Still need to watch for dysrhythmias & cardiogenic shock with Ideally, if Takotsubo CM suspected  cardiac catheterization should be chosen over fibrinolytics

Further Discussion Dr. Hunter Young, former Barker ACS