Discussion

Traditionally, cardiac surgeons avoided making an incision on the left ventricle surface for fear of jeopardising ventricular function, increasing the risk of aneurysm formation, and causing ventricular arrhythmia. ^{Reference Hanna, Colan and Bridges5} The concern arose as a result of traditional animal experiments. Benzing et al. reported at least moderate LV function depression. ^{Reference Benzing, Baker and Stockert1} Waldhausen et al., similarly, demonstrated depressed left ventricle function with longitudinal incision and more pronounced depression with transverse incision. ^{Reference Waldhausen, Herendeen and Taybi3} Another animal study, on the other hand, supported the idea of preserved ventricular function after left ventriculotomy. ^{Reference Replogle, Kundler and Gross2} Recently, it was demonstrated that apical left ventriculotomy only impairs major axis function and is expected to be better tolerated. ^{Reference DiBernardo, Kirshbom and Skaryak6} Aside from the experimental data, the first clinical data came from patients undergoing subaortic muscular stenosis repair with left ventriculotomy, who had postoperatively preserved left ventricle function. ^{Reference Taber and Green7,Reference Julian, Dye and Javid8} The Mayo Clinic group recently published their experience with left ventriculotomy for ‘apical myectomy’ with good outcomes. ^{Reference Schaff, Brown and Dearani9} Similarly, with acceptable morbidity and mortality rates, intracardiac repair of multiple ventricular septal defects began to be performed via left ventriculotomy. ^{Reference McDaniel, Gutsell and Nolan10,Reference Shin, Jhang and Park11}

Two major contributing factors for the negative effects of left ventriculotomy were identified in studies. First, the spiral muscle fibres are disrupted, and myocardial architecture is destroyed. Second, the coronary blood supply to the affected myocardium is interrupted. ^{Reference DiBernardo, Kirshbom and Skaryak6} We demonstrated that left ventriculotomy had no negative effect on postoperative ventricle function, as represented by EF and FS. We believe that our meticulous surgical technique, which included a short and limited longitudinal incision on the left ventricle apex parallel to the left anterior descending (LAD) while preserving the LAD and its branches, reduced risks. Furthermore, we believe that excessive traction on the ventricular wall during repair contributes to myocardial injury. Thus, we believe that using stay sutures on the edges rather than direct application of retractor prevents iatrogenic injury. Because we required a left ventriculotomy to remove various cardiac masses in children, a small incision and soft traction with stay sutures provided adequate exposure. One might wonder if the same standards apply when the incision is used for ventricular septal defect (VSD) closure, which necessitates more traction and surgical manipulation around the incision. We did not include any patients with multiple VSD in our cohort because we prefer a ‘hybrid’ approach for these patients. In a study of 23 patients published by Wollenek et al., there were no adverse effects on ventricular function and satisfactory late follow-up results were reported. ^{Reference Wollenek, Wyse and Sullivan12} A more recent study reported their experience in five patients, three of whom had VSD closure. They also demonstrated that left ventriculotomy had no negative effect on ventricle function. ^{Reference Goldberg, Knott-Craig and Joshi13}

Particularly regarding the arrhythmia complication, no arrhythmia was detected during the post-operative period or at the most recent follow-up. Myocardial fibrosis was thoroughly studied as the underlying mechanism of ventricular arrhythmia after left ventricle incision. It certainly warrants long-term monitoring, but the absence of arrhytmia after almost 2.5 years of surveillance is encouraging.

In spite of the widespread negative perception of left ventriculotomy among cardiac surgeons, we demonstrated in this study that meticulously made incisions on the left ventricle did not compromise ventricular function after surgery and during follow-up. The post-operative course followed current trends in the care of these patients. Also, other potential side effects such as arrhythmia and pseudoaneurysm were not observed. Therefore, left ventricuolotomy can safely be applied in appropriately selected patients.

The limitations of this study include its single centre, retrospective, and observational nature, as well as the small number of subjects. Furthermore, longer-term follow-up is inevitably needed; however, we believe the current study contributes to a body of knowledge that challenges the myth that left ventriculotomy is dangerous. From our experience, we would advise that when indicated, left ventriculotomy for access to the left ventricle, is a safe, well-tolerated incision with minimal negative short- or medium-term effect.