A 55-year-old man presented seeking a second opinion after recovery from a cardiac arrest. He had a history of esophagitis, hiatal hernia, and dyslipidemia. Otherwise, the patient had enjoyed overall good health and had no known hypertension. He exercised regularly, including playing racquetball on a regular basis. A year and a half ago, his primary care provider evaluated him for an abnormal electrocardiogram (ECG), and he underwent a nuclear stress test with apparent normal results. The patient reportedly had a normal catheterization about 6 to 7 years before this visit as part of an evaluation for chest pain. He described the results as normal. Approximately 3 months before the cardiac arrest, he had one episode of transient syncope lasting 10 to 20 sec while playing racquetball. He did not seek medical care at the time.
On the day of the cardiac arrest, he played racquetball as usual. Later that night, when going to sleep at home, he felt ill and within 1 to 2 min lost consciousness. His wife started CPR and called 911; paramedics administered intravenous epinephrine and DC shock with restoration of sinus rhythm. The patient was taken to a local hospital where an ECG was performed (Figure 1) and he was placed on a hypothermia protocol. He subsequently went back into cardiac arrest with ventricular fibrillation (VF), requiring multiple electrical shocks to resuscitate. A review of hospital records showed a mild troponin elevation of 1.8 ng/mL.
QUESTION 1: What do you suspect?
Explanation: The ECG shows diffuse, deep T wave inversion which could be due to ischemia, but in the presence of increased QRS voltage is more likely to be due to apical hypertrophic cardiomyopathy.
Video 1: Left anterior descending artery catheterization https://youtu.be/kdFB5tk17fU
Video 2: Left circumflex artery catheterization https://youtu.be/-gm_yBs8jd8
Video 3: Right coronary artery catheterization https://youtu.be/MqxZFTJSXHI
Video 4: Ventriculography https://youtu.be/0xp3XvCH6rk
QUESTION 2: What would you do next?
ANSWER: D: All of the above
Given the ECG findings, choices AC are all appropriate. The coronary angiogram showed a moderate lesion in the proximal RCA and a moderate-to-severe lesion in the left circumflex artery. Nevertheless, because of the acuity of the presentation and suspicion of an acute ischemic presentation, PCI was performed on the left circumflex artery, which was interpreted as site of the culprit lesion. The left ventricular (LV) angiogram showed a hyperdynamic ventricle with apical trapping and an apical aneurysm.
Next, an echocardiogram was performed. Video 5 shows a parasternal long axis view.
Video 5. Echocardiography https://youtu.be/LKfsY6ftBsM
QUESTION 3: What would you do next?
The LV angiogram (Video 4) and the echocardiogram showed typical features of apical hypertrophic cardiomyopathy with apical trapping and a small apical aneurysm (best seen in the angiogram). The ECG findings were quite consistent with this diagnosis. The mild troponin elevation suggested an acute injury, but it is unlikely that this would account for the small apical aneurysm seen in the angiogram. Thus, our choice would be an AICD before discharge given that the possible ischemic event did not appear sufficient to explain the multiple episodes of VF. However, the patient was discharged from the facility without an AICD and with instructions to come back for follow-up.
Since discharge (3 weeks before this clinic visit), the patient has been doing well. He exhibits no symptoms of ischemia, heart failure, or low forward perfusion symptoms. He walks slowly 1 to 2 miles a day.
Physical examination. When the patient presented at our clinic, his blood pressure was 110/70 mm Hg and his heart rate was 70 bpm. He was afebrile and in no distress. The examination was unremarkable except for a soft early systolic murmur at the left sternal border that did not change with maneuvers.
Imaging. Upon review of the available records (catheterization and echocardiogram), we requested cardiac magnetic resonance imaging (CMR) to better assess the extent of the hypertrophy and the apical aneurysm, and look for perfusion defects and scarring that would place the patient at higher risk for subsequent electrical instability (Video 6, Figure 2).
Video 6. Cardiac magnetic resonance imaging (CMR) shows findings diagnostic of apical HCM with cavity obstruction and a small apical aneurysm. https://youtu.be/dFsycAQ69vQ
Next we performed repeat coronary angiography to assess FFR in the RCA territory. FFR was normal at 0.83, and we decided against PCI. However, we felt that the patient had a high risk for subsequent cardiac arrest episodes, so we decided to implant an AICD, which was done without complications. Four months after AICD placement, the patient is doing well.
Apical aneurysm in hypertrophic cardiomyopathy (HCM) is a relatively under-diagnosed finding with reported diagnosed incidences of 2 to 3 in patients with apical HCM.1 For a long time, HCM with apical variant was considered a relatively benign disease, but within the last few years, data is coming to light that demonstrates otherwise.2
An apical aneurysm is a discrete, thin-walled akinetic or dyskinetic segment of the most distal portion of the LV chamber. Diagnosis is often made by echocardiography, but in many cases, ultrasound contrast is needed for more accurate detection. Left ventricular angiography and CMR can provide a definitive diagnosis when echocardiography is equivocal.3
In a recent review by Rowin et al., apical aneurysms were identified in 4.8 of 1940 consecutive patients with HCM. A higher percentage of patients with apical aneurysm developed ventricular arrhythmias, including ventricular tachycardia (VT) and ventricular fibrillation (VF). One third of patients with an ICD implanted required appropriate shock therapy for VT or VF. Furthermore, thromboembolic events were noted in around 5; however, the sample was too small to clearly define a role for chronic anticoagulation.2
Sudden cardiac death risk calculators for HCM do not account for an LV apical aneurysm. However, given recent data, we believe that this finding should be considered as a stand-alone sudden cardiac death (SCD) risk factor. Furthermore, detection of scar within the aneurysm and reduced perfusion are likely to be markers for higher SCD risk given that, in the population of patients with HCM, these findings are associated with higher incidence of VT and/or VF.
In view of our patient's prolonged cardiac arrest and resuscitative process (both before and after hypothermia), we did not think that a peak troponin of 1.8 ng/mL pointed toward ACS as the cause of his cardiac arrest cardiac arrest; a primary arrhythmic event was a more likely cause.