Conduction gap mapping of linear ablation lesions with high-density mapping.

INTRODUCTION: When performing linear ablation, creating contiguous and transmural lesions are technically challenging due to the difficulty in finding electrical conduction gaps. We hypothesized that high-density mapping could identify the gaps. METHODS AND RESULTS: This study included consecutive patients who underwent conduction gap mapping of de novo lesions (41 patients, 55 lines) and previous lesions (25 patients, 34 lines). We analyzed the utility of bipolar and unipolar conduction gap mapping and retrospectively assessed the voltage and morphology of the bipolar electrograms at the gap sites. Bipolar and unipolar propagation maps were classified into three types: the propagation wavefront traveled through the linear ablation lesions (direct leak), the wavefront jumped to an opposite site across the line and returned to the line (jump and return leak), and others (indefinite leak). In the jump and return leak maps, the site where it returned suggested a conduction gap site. Bipolar propagation maps identified 30 (54.5%) conduction gaps and unipolar maps identified 40 (72.7%) gaps at de novo linear ablation lesions (P = .01), and 32 (94.1%) gaps and 33 (97.1%) gaps, respectively, at previous lesions (P = .56). Bipolar voltage mapping did not add any further efficacy in detecting conduction gaps, and the morphology of the electrograms recorded at the gap sites was not related to the types of propagation maps. CONCLUSION: Conduction gaps of linear ablation lesions can be visualized by high-density mapping with a high probability. Unipolar propagation, when used with bipolar mapping, may help detect conduction gap sites.

Aortic Mural Thrombus Associated with Congenital Protein C Deficiency in an Elderly Patient.

Thrombophilia increases the risk of venous thrombosis, but is rarely responsible for aortic thrombosis. Aortic mural thrombus (AMT) may be associated with a protein C deficiency. However, it is necessary to determine whether the protein C deficiency is congenital/hereditary or secondary/acquired (consumption of protein C during the process of thrombus formation). This study describes a 77-year-old Japanese woman with incidentally diagnosed AMT, who had a protein C deficiency (activity 54%, antigen 42%). Sequencing of the protein C gene revealed a heterozygous mutation of c.1268delG, p.Gly423Valfs＊82 in exon 9, indicating a congenital protein C deficiency. These findings indicate that very late onset AMT can occur in an adult with congenital protein C deficiency.

A Case of Acute Myocardial Infarction due to Left Main Trunk Occlusion Complicated With Aortic Dissection as Diagnosed by Intravascular Ultrasound.

A 52-year-old man was transferred to our hospital with a sudden onset of severe chest pains. His electrocardiogram revealed ST-segment elevation suggestive of acute myocardial infarction. Emergency coronary angiography showed subtotal occlusion of left main trunk (LMT) with delayed coronary flow. Because intravascular ultrasound revealed a large intimal flap, we diagnosed aortic dissection involving the LMT. After stenting of the LMT, the patient underwent surgical repair of the aortic dissection. Although it is difficult to obtain a correct diagnosis of aortic dissection complicated with myocardial ischemia, we succeeded in diagnosing this rare condition by use of a intravascular ultrasound.