Transesophageal Echocardiography During Ventricular Fibrillation
Sudden cardiac death is most frequently caused by spontaneous onset of ventricular fibrillation (VF), during which the rhythmic heart contractions transform into chaotic, vermiform, and inefficient activity of the myocardium while the pulsatile pulmonary and systemic blood flow circuits stop. Little information is available on the anatomical and hemodynamic changes that occur during VF. These changes could be seen in humans with transesophageal echocardiography (TEE).
In the present report, we describe an 81-year-old man with a history of hypertension and upper gastrointestinal bleeding who was admitted with paroxysmal atrial fibrillation with high ventricular response (160 bpm) and heart failure. Given the impossibility of anticoagulation and to control hemodynamic compromise, TEE was performed before direct-current cardioversion. TEE showed left ventricular hypertrophy with normal ejection fraction and mild left atrial dilation (diameter 5 cm, area 29 cm2) and ruled out thrombus in the left atrium. Direct-current cardioversion was performed without removing the probe, but synchronized cardioversion failure and VF appeared on the ECG. This was defibrillated immediately with 360 J, and the rhythm of atrial fibrillation was restored. Four shocks were performed previously (100, 200, 300, and 360 J), but all of them were unsuccessful. The patient’s hemodynamic failure stabilized after the heart rate was reduced with amiodarone.
During the iatrogenic VF, TEE (online-only Data Supplement Movie I) demonstrated fast chaotic cardiac oscillation, seen more clearly in the ventricles, which decreased the systolic volume. The mitral and aortic valves assumed a half-open position and showed oscillatory movement.
After onset of the VF, weak spontaneous echocardiographic contrast (SEC) into the right atrium was seen, but no SEC into the left ventricle was seen. Otherwise, a dense SEC with a smoke-like appearance quickly occupied the left atrium; its echocardiographic reflectivity increased gradually within a few seconds (Figure A). The SEC did not enter the left ventricle, which indicated that the rapid succession of myocardial contractions did not allow diastolic ventricular expansion, but at the level of the mitral valve, the SEC showed a regular “washout” phenomenon, which indicated mitral regurgitation. After interruption of the VF and the onset of a basic rhythm, the dense SEC was flushed away completely with just a few cardiac contractions (Figure B). To the best of our knowledge, this type of complication of direct-current cardioversion, with documentation by TEE of myocardial wall motion kinetics, valves, and blood flow, has not been reported previously.
When VF occurred, TEE showed that the heart reduced abruptly the end diastolic left ventricular volume and assumed a systolic configuration, whereas myocardial contractions were still observed, although they were ineffective. Furthermore, their rapid succession did not allow diastolic ventricular expansion. A dense SEC with a smoke-like appearance quickly occupied the left atrium. After interruption of the VF and the onset of basic rhythm, the dense SEC was flushed away completely with just a few cardiac contractions.
The online-only Data Supplement is available with this article at http://circ.ahajournals.org/cgi/content/full/120/7/e43/DC1.
↵*Drs Cianciulli and Saccheri are researchers for the Secretary of Health, Government of the City of Buenos Aires.