THROMBOLYSIS IN MYOCARDIAL INFARCTION FRAME COUNT IN TAKOTSUBO CARDIOMYOPATHY

Abstract

Takotsubo cardiomyopathy (TC) in its typical form, is characterizedby transient systolic dysfunction of the apical and/or mid segments ofthe left ventricle that mimic myocardial infarction (MI), but in the ab-sence of significant coronary artery disease [1–3]. Common triggeringfactorsincludeacutemedicalillness,severeemotionalorphysicalstresse.g., unexpected death of relatives, domestic violence, arguments, cata-strophic medicaldiagnoses,financialor gambling losses and naturaldi-sasters [2,3]. Pathogenesis remains unclear although catecholamine-mediated myocardial stunning, multivessel coronary vasospasm andabnormalities in coronary microvascular function have been proposedas possible explanations [2,3]. TC has strong female preponderancewith nearly 90% cases involvingpostmenopausal women [3,4]. Patientscommonly present with substernal chest pain. Electrocardiographicchanges include ST-segment elevation, T-wave inversion, QT-intervalprolongation, abnormal Q-waves or non-specific abnormalities [1–3].Elevations in cardiac biomarkers are typically less pronounced than inacute anterior ST-segment elevation myocardial infarction (STEMI)and coronary angiography does not revealobstructive coronary diseaseor plaquerupture correspondingto thewall motion abnormalitiesseenin this condition [1–4].MayoCliniccriteriaiscommonlyusedfordiagnosisandrequiresfol-lowing four conditions: a) transient hypokinesis, akinesis or dyskinesisoftheleftventricularmidsegmentswithorwithoutapicalinvolvement,b) absence of obstructive coronary disease or acute plaque rupture,c) new electrocardiographic abnormalities (ST-segment elevation and/orT-waveinversion)ormodestelevationincardiactroponin,andd)ab-sence of pheochromocytoma or myocarditis [5,6]. However thesecriteria are considered outmoded and newer versions have been pro-posed which suggest that myocarditis and TC can coexist and don'thave to be mutually exclusive [5,6]. Supportive measures are themain-stay of management. Patients generally receive aspirin, β-blockers,angiotensin-converting-enzyme inhibitors, and intravenous diuretics ifneeded. Hypotension in the setting of left ventricular outflow tract ob-struction may warrant use of beta-blockers and phenylephrine. In se-vere left ventricular dysfunction, inotropic agents or an intraaorticballoonpumpmayberequired [1–4].Prognosisisexcellent,withnearly95%ofpatientsexperiencingcompleterecoverywithin4–8weeks[3,4].Gibson et al. [7] introduced the TIMI frame count (TFC) method formeasuring coronary flow velocity from coronary angiograms. It is de-fined as ‘the number of frames required for contrast material to travelfrom the coronary ostium to the distal landmark’ [7]. The objective ofour study isto determineif TFC isa useful tool in determiningthecoro-nary flow in TC patients [8].Sixteen patients were identified at our institute with an apparentacute anterior-STEMI presentation but were subsequently diagnosedwith TC. They were retrospectively compared with randomly chosencontrolswithout coronary artery disease on angiography. Microcircula-tory analysis was done via calculation of TFC (Gibson technique) in allthree major vessels. Left anterior descending (LAD) artery values wereadjusted (by applying a correction factor) to get ‘corrected TIMI-Frame-Count’ (CTFC). This was done to compensate for the longerlengthofLADandcalculatedbydividingthenumberofframesrequiredfor the dye to pass through the LAD by 1.7. Data was analyzed usingExcel-2007 software. Mean ± Standard Deviation are given for quanti-tative variables (Table 1). Frequencies, percentages and graphs aregiven for qualitative variables (Table 2). Two-independent sample t-test was applied to observe group mean differences. p-Value of b0.05was considered to be statistically significant.Patients were divided into two groups viz. cases and controls. Caseshad 16 patients (all females), while controls had 15 (9 females; 6males). Mean ages of the cases and control groups were 68.31 ±10.88 years and 66.5 ± 14.28 years respectively. Mean-CTFC for LADin cases was 19.61 ± 5.77 and in controls it was 16.65 ± 2.41 (statisti-cally significant difference, p-value = 0.04 (table/Fig. 1)). Mean-CTFCfor Circumflex artery was 18.93 ± 3.87 and 18.06 ± 3.95 in cases andcontrols respectively (no statistically significant difference p-value =