(190 days)
The Mercator Atrial High-Density Array Catheter, used in conjunction with the Cardiac Pathways' Model 8100 Arrhythmia Mapping System and the Model 8300 Signal Acquisition Module, is intended to be used in the right atrium of patients with complex arrhythmias that may be difficult to identify using conventional mapping systems alone (i.e., linear mapping catheters). The system is used to record intracardiac electrogram (EGM) signals and to deliver pacing pulses for the purpose of diagnostic provocative stimulation during an electrophysiology procedure.
The Mercator High Density Array Catheter has an 8.5F catheter shaft with a collapsible, spheroidal-shaped, 32 bipole electrode array on the distal end, and an integrated cable/connector assembly on the proximal end. The device is designed to interface with the Cardiac Pathways' Arrhythmia Mapping System. There are three sizes of arrays for the right atrium based on the atrial volume derived from transthoracic echocardiograms: 70 cc, 100 cc, and 130 cc.
The electrode array consists of eight equidistant arms fixed at each end to form a spheroid. The arms terminate into an atraumatic tip on the distal end, and transition into the catheter shaft on the proximal end. The arms are made of a compliant material that maintains contact against the atrial walls during the cardiac cycle. The arms are labeled A through H in a clockwise direction. The array orientation is ascertained using three radiopaque markers positioned on arms A (distal), B (mid) and C (proximal). Each arm has four electrode pairs spaced equidistant from each other along the length of each arm. Each electrode is 0.75 mm wide by 0.25 mm high. The electrode spacing is the same for all three sizes of catheters: 1 mm between electrodes in a bipole and 8 mm between bipoles when measured center to center.
The electrical connections between the electrodes on the array and the connector on the proximal end of the catheter are made via cables. The cables run the length of the catheter shaft and connector bump tubing. The catheter shaft terminates at the proximal end at the Y-arm assembly. The center lumen of the catheter is contiguous with the luer fitting on the straight arm of the Y-arm assembly and is used for flushing the catheter. The angled arm on the Y-arm assembly provides the interface for the connector bump tubing.
The connector has 79 pins, and interfaces with a mating receptacle on the Arrhythmia Mapping System. The terminations of the cables at the connector are housed inside a backshell that provides a smooth transition from the connector to the connector burnp tubing.
The 11 F Guiding Sheath and the 30° Angled Guiding Sheath have an 11 F braided catheter shaft that terminates into a short, atraumatic tip on the distal end and a luer fitting on the proximal end. On the 30° Angled Guiding Sheath, the distal 4.5 cm of the catheter shaft is angled 30° from the proximal shaft of the catheter. The 11 F Guiding Sheath and the 30° Angled Guiding Sheath are used in conjunction with the 8.5 F Pigtail Catheter and the 30° Angled 8.5 F Pigtail Catheter, respectively, to position the High Density Array Catheter in the right atrium.
The 11 F Guiding Sheaths have a large inside diameter through which the High Density Array Catheter is inserted into and withdrawn from the cardiovascular system. The shaft of the Guiding Sheath is radiopaque. The Guiding Sheath terminates into a female luer fitting on the proximal end. This luer fitting is used to flush the Guiding Sheath and to introduce the High Density Array Catheter into the Guiding Sheath. The working length of the Guiding Sheath is 110 cm.
The purpose of the Guiding Sheath is to "guide" the High Density Array Catheter to a position in the right atrium found using the 8.5 F Pigtail Catheter. The Guiding Sheath is also used to collapse and withdraw the electrode array on the High Density Array Catheter when mapping is complete
The 8.5 F Pigtail Catheter and the 30° Angled 8.5 F Pigtail Catheter have an 8.5 F braided catheter shaft on the proximal end attached to a soft distal extrusion that is necked down and formed into a radius known as a " pigtail". The 8.5 F Pigtail Catheter and the 30° Angled 8.5 F Pigtail Catheter are used in conjunction with the 11 F Guiding Sheath to position the High Density Array Catheter in the right atrium.
The Pigtail Catheters have an open center lumen and 12 side holes positioned equidistant from each other in the distal extrusion, proximal to the pigtail. These holes can be used to deliver contrast media into the right atrium for visualization of catheter position and to assess the size of the atrium. The center lumen is accessible for flushing using a female luer lock fitting on the proximal end of the Pigtail Catheter. The braided shaft is radiopaque and gives the catheter good torque transmission.
The diameter of the pigtail tip is 1.3 cm. The purpose of this large diameter tip is to facilitate atraumatic placement into the right atrium. It also helps to avoid prolapsing of the High Density Array Catheter through the tricuspid valve into the right ventricle. The working length of the Pigtail Catheter is 135 cm.
A pigtail stylet is packaged in the Deployment Kit to straighten out the distal radius of the pigtail when inserting it inside the Guiding Sheath. The stylet is a stainless steel mandrel with a ball on the end to prevent advancing it all the way into the center lumen of the Pigtail Catheters. The pigtail stylet is used only in the preparation of the Guiding Sheath/Pigtail Catheter assembly and is not intended to be inserted into a patient. It is removed after the Pigtail Catheter is positioned inside the Guiding Sheath.
The Mercator Atrial High Density Array Catheter is intended to record intracardiac electrogram (EGM) signals and to deliver pacing pulses for diagnostic provocative stimulation during an electrophysiology procedure in the right atrium of patients with complex arrhythmias.
Here is an analysis of its acceptance criteria and the study proving its performance:
1. Acceptance Criteria and Reported Device Performance
The provided document does not explicitly list quantitative acceptance criteria for the device's performance. Instead, it focuses on demonstrating substantial equivalence to predicate devices. The performance data assesses diagnostic quality, signal quality, rhythm interpretations, and baseline noise compared to standard catheters. Since the device is intended to enable diagnosis, the ability to successfully record and interpret signals is paramount.
| Performance Metric | Acceptance Criteria (Implied by Equivalence Study) | Reported Device Performance |
|---|---|---|
| Diagnostic Quality (Sinus Rhythm) | Equivalent to standard diagnostic commercial catheters (p=1.000) | Overall diagnostic quality in sinus rhythm rated as "identical" between HDAC and standard catheters (p = 1.000). Recordings acceptable for diagnosis in all patients with both devices. Rhythm diagnosis was sinus rhythm in all cases with both devices. |
| Signal Quality (Sinus Rhythm) | Similar to standard diagnostic commercial catheters (p=0.8643) | Overall signal quality in sinus rhythm rated as "similar" between HDAC and standard catheters (p = 0.8643). |
| Diagnostic Quality (Atrial Arrhythmia) | Similar to standard diagnostic commercial catheters (p=0.1177 and Kappa = 0.799) | Overall diagnostic quality in atrial arrhythmia rated as "similar" between HDAC and standard catheters (p = 0.1177). Recordings acceptable for diagnosis in all patients with both devices. Arrhythmia diagnoses were similar with the two devices (Kappa = 0.799). |
| Signal Quality (Atrial Arrhythmia) | No difference from standard diagnostic commercial catheters (p=0.4559) | Overall signal quality in atrial arrhythmia showed "no difference" among catheters (p = 0.4559). |
| Baseline Noise | Equivalent to standard diagnostic commercial catheters (p=0.5450 for mean, p=0.8970 for patient mean) | Mean baseline noise per electrode pair: 0.019 ± 0.096 mV for HDAC vs. 0.016 ± 0.075 mV for standard catheters (p = 0.5450). Proportion of electrode pairs with baseline noise: 6.8% for HDAC vs. 7.6% for standard catheters. Mean baseline noise per patient was similar for both devices (p = 0.8970). Equivalence was demonstrated regardless of comparison method. |
| Pacing Capture Consistency | High consistency (no specific threshold given, but "consistent capture" is implied as positive performance feedback) | Consistent capture of one or more bipole pairs at 5 mA was achieved in 96.9% of patients. Pacing capture was also determined at 2 mA. |
| Safety Profile | Excellent safety profile compared to comparison groups, no major adverse events related to the device itself (e.g., thromboembolism, perforation, valve injury, thrombus on catheter) | No instances of thromboembolic events, cardiac perforation, or valve injury reported. No evidence of thrombus on 92 inspected HDAC catheters. One procedure-related major adverse event (left femoral hematoma) not directly attributed to the device design itself. Three minor, procedure-related adverse events occurred, also not directly attributed to the device design. |
2. Sample Size and Data Provenance
- Test Set Sample Size: 74 patients for data analysis in the clinical study. A total of 79 patients were enrolled, but 5 were excluded because the HDAC was not deployed.
- For matched electrogram analysis in sinus rhythm: 41 patients.
- For matched electrogram analysis in atrial arrhythmia: 45 patients.
- Data Provenance: Prospective clinical study conducted at eight centers. The country of origin is not explicitly stated, but given the FDA 510(k) submission, it is almost certainly a US-based study or a multinational study that includes US sites.
3. Number of Experts and Qualifications for Ground Truth
- Number of Experts: A "blinded independent expert" was used to perform the primary analyses of equivalence. Only one expert is explicitly mentioned for this comparative assessment.
- Qualifications of Experts: The specific qualifications (e.g., "Radiologist with 10 years of experience") are not detailed for the independent expert, only that they were an "expert." For an electrophysiology study, such an expert would typically be an electrophysiologist with significant experience in interpreting intracardiac electrograms.
4. Adjudication Method
The document states that the "primary analyses of equivalence... were performed by a blinded independent expert." This suggests a single expert's interpretation formed the basis of the comparison without an explicit multi-reader adjudication method (e.g., 2+1 or 3+1 consensus). However, the study also compared diagnoses to "predefined diagnostic categories," implying a structured framework for assessment.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No Multi-Reader Multi-Case (MRMC) comparative effectiveness study was explicitly mentioned to assess how much human readers improve with AI vs. without AI assistance. The study focuses on the standalone performance of the device and its equivalence to predicate devices, with human readers (the "independent expert") evaluating the quality of the signals from both the investigational and predicate devices. This device is a diagnostic catheter, not an AI assistance tool.
6. Standalone Performance Study (Algorithm-Only)
A standalone performance study was done in the sense that the device's ability to record and pace was evaluated on its own merits alongside the comparison to predicate devices. The study assessed:
- The device's ability to capture pacing (96.9% consistent capture at 5 mA).
- The intrinsic qualities of its recorded electrograms (diagnostic quality, signal quality, baseline noise) as interpreted by an expert, compared to standard catheters.
- The device's mechanical and electrical specifications compliance through laboratory testing. These are inherently "standalone" assessments of the device itself.
7. Type of Ground Truth Used
The ground truth for the clinical study was primarily established by:
- Expert Interpretation/Diagnosis: The "blinded independent expert" determined the diagnostic quality, rhythm diagnoses, and signal quality based on the electrogram recordings. This represents expert consensus on the interpretation of physiological signals.
- Patient Diagnosis/Medical History: The study population itself had verified arrhythmias (e.g., atrial flutter, AV nodal tachycardia), which served as the clinical context for evaluating the diagnostic performance of the catheters.
- Objective Measurements: For baseline noise, objective measurements (peak-to-peak absolute amplitude) were taken from the signals.
8. Sample Size for the Training Set
This document describes a clinical validation study and does not mention a "training set" in the context of an AI/machine learning algorithm, as the device itself is a physical medical instrument (catheter), not a software algorithm that requires a training set. The clinical study acts as the validation set for the device's performance against its intended use.
9. How the Ground Truth for the Training Set was Established
As mentioned above, there is no "training set" in the context of an AI/machine learning algorithm for this device. The physical device's design and engineering would have been guided by prior medical knowledge, engineering principles, and potentially animal or bench testing (which are not detailed here for ground truth establishment). The ground truth for the clinical validation was established through expert interpretation of electrograms and patient clinical diagnosis.
§ 870.1220 Electrode recording catheter or electrode recording probe.
(a)
Identification. An electrode recording catheter or an electrode recording probe is a device used to detect an intracardiac electrocardiogram, or to detect cardiac output or left-to-right heart shunts. The device may be unipolar or multipolar for electrocardiogram detection, or may be a platinum-tipped catheter which senses the presence of a special indicator for cardiac output or left-to-right heart shunt determinations.(b)
Classification. Class II (performance standards).