The use of an entirely subcutaneous implantable Cardioverter defibrillator (S-ICD) is a better alternative for patients who have limitations to placing pacemaker leads intravenously. We report a case of S-ICD use because of presence of right ventricle thrombus.
A 59 -year-old male with a history of Ischemic heart disease on medical therapy presented with progressive dyspnea, intermittent dizziness and near syncopal episodes. On examination, the patient was alert and fully oriented. The pulse rate was 58 beats per minute, the blood pressure 125/70 mmHg, the respiratory rate 16 breaths per minute and oxygen saturation was 98 % while breathing ambient air. The breath sounds were normal. The heart sounds were heard, with soft systolic murmur at the left sternal border. The remainder of the examination was unremarkable. On the same day of admission, he developed cardiac arrest with documented ventricular fibrillation and was successfully resuscitated. Transthoracic echocardiogram revealed a moderately enlarged left ventricle with severely depressed systolic function (LVEF=15%). There was large protruding fixed thrombus attached to LV apex. Thrombus was also seen in right ventricle apex (pictures). Optimal medical therapy was continued for the heart failure. Because of the clinical findings, ICD was indicated. He received an S-ICD instead of transvenous route due to the presence of thrombus in the right ventricle. Device interrogation revealed satisfactory parameters. The patient was discharged without any further event.
An entirely subcutaneous ICD has been demonstrated to be a reliable and effective system for detection and termination of ventricular arrhythmias and potentially avoiding many of the complications associated with transvenous ICDs. The case presented illustrates one of the several advantages of the subcutaneous approach that may make it a preferred rather than simply an alternative to transvenous ICD.
In our literature search, there was no report of use of S-ICD because of right ventricle thrombus. It is well documented that transvenous pacemaker leads may result in thromboembolic complications. Placement of transvenous pacing lead in the presence of a right ventricle thrombus would potentially have deleterious consequences.
There still remain several limitations to use of S-ICD mainly because of the absence of pacing ability. It cannot be applied to patients requiring pacing for bradyarrhythmias, resynchronization therapy for heart failure, and antitachycardia pacing. The aforementioned therapies were not indicated in the case presented. Future studies and observations will better define patient target groups and establish the therapeutic potential of the subcutaneous device technology.
The case illustrates the preferable use of a subcutaneous ICD in selected clinical presentations, one of which is presence of right ventricle thrombus.