Papillary muscle rupture after inferolateral STEMI — case discussion

Presentation

Practice case (not a real patient). A 72-year-old woman in a regional Australian hospital without cardiac surgery presented 16 hours after the onset of chest pain with an inferolateral STEMI and had PCI to an occluded circumflex artery.^[7] On day 3 she becomes acutely breathless, with pulmonary oedema, a systolic blood pressure of 78 mmHg, cool peripheries and rising lactate.^[7] No new murmur is heard. Her jugular venous pressure is not raised and her heart sounds are normal.^[7]

Step 1 — What is happening?

Discussion:

• ESC 2023 says sudden hypotension and pulmonary congestion after MI should raise suspicion of a mechanical complication, and that immediate echocardiographic assessment is indicated.^[1]
• Papillary muscle rupture fits: the AHA 2021 statement says posteromedial rupture typically occurs with inferior or lateral STEMI, commonly within days, and roughly half of patients present with pulmonary oedema that may quickly progress to cardiogenic shock.^[7]
• The absence of a murmur does not exclude it: a murmur may be absent because left atrial and LV pressures equalise rapidly.^[7]
• Contemporary patients with mechanical complications tend to be older and female, to have a history of heart failure or chronic kidney disease, and often present with their first acute MI; patients with large infarcts or those who do not receive timely revascularisation remain at risk (AHA 2021).^[7]

Step 2 — Imaging

Emergency transthoracic echocardiography shows a severe, eccentric mitral regurgitant jet and a mobile mass in the LV prolapsing into the left atrium, with preserved LV function.^[7]

• ESC 2023: emergency TTE is recommended in suspected ACS with cardiogenic shock or suspected mechanical complications (Class I, Level C).^[1]
• The AHA 2021 Table 1 echo findings of papillary muscle rupture are a severe and often eccentric MR jet and a mobile mass in the LV, sometimes prolapsing into the left atrium.^[7]
• Had TTE been non-diagnostic, as it can be in partial rupture, transoesophageal echo has a high diagnostic sensitivity (AHA 2021).^[7]

Step 3 — Stabilise and transfer

Discussion:

• ACC/AHA 2025: patients with a mechanical complication of ACS should be managed in a facility with cardiac surgical expertise (COR 1, LOE C-EO); haemodynamic deterioration is unpredictable and can be precipitous.^[2]
• ESC 2023: an IABP should be considered for haemodynamic instability or cardiogenic shock due to ACS-related mechanical complications (Class IIa, Level C); ACC/AHA 2025 notes favourable haemodynamic effects of an IABP in acute ischaemic MR.^[1][2]
• ESC 2026 (temporary MCS in cardiogenic shock): temporary MCS should be considered for MI-related mechanical complications as a bridge to definitive treatment (Class IIa, Level C), with passive IABP or active percutaneous MCS chosen by the Shock Team on shock severity.^[3]
• The AHA 2021 statement says positive pressure ventilation can improve gas exchange and haemodynamics by reducing LV preload and afterload and MR; intravenous nitroglycerin or nitroprusside to reduce afterload in the critical care environment is described for haemodynamically stable patients, which she is not.^[7]

Step 4 — Definitive treatment

Discussion:

• The AHA 2021 statement calls acute papillary muscle rupture a surgical emergency requiring immediate evaluation by a surgical team, and says emergency mitral valve replacement is the treatment of choice.^[7]
• ESC 2023: with haemodynamic instability, emergency surgical or catheter-based repair is recommended, based on Heart Team discussion (Class I, Level C).^[1]
• ESC 2023 narrative: when coronary revascularisation is needed, CABG is recommended at the time of surgical repair; NHFA/CSANZ 2025 says perform CABG at the time of surgery in STEMI or ACOMI with mechanical complications and mitral valve disease (strong recommendation, low certainty).^[1][6]
• If surgical risk were prohibitive, transcatheter edge-to-edge mitral repair can be considered in select patients as part of a Heart Team approach (AHA 2021).^[7]

Step 5 — After surgery

She survives mitral valve replacement. Before discharge the team reviews LV function and goals of care.^[2][7]

• ACC/AHA 2025: an assessment of LVEF is recommended before hospital discharge to guide therapy and for risk stratification (COR 1, LOE C-LD).^[2]
• The AHA 2021 statement gives hospital mortality of 10–40% for papillary muscle rupture with acute MR.^[7]
• It also says palliative care consultation should be considered early in the course of acute MI, especially if risk factors for morbidity and mortality are high.^[7]

Learning points

• Suspect a mechanical complication with sudden hypotension, recurrence of chest pain, a new murmur suggestive of acute mitral regurgitation or a ventricular septal defect, pulmonary congestion or jugular vein distension after MI, and get an immediate echo (ESC 2023).^[1]
• A murmur may be absent in papillary muscle rupture (AHA 2021).^[7]
• Manage a mechanical complication of ACS in a facility with cardiac surgical expertise (ACC/AHA 2025, COR 1, LOE C-EO); consider an IABP for haemodynamic instability or cardiogenic shock due to an ACS-related mechanical complication (ESC 2023, Class IIa, Level C), and, in cardiogenic shock, temporary MCS for mechanical complications related to MI as a bridge to definitive treatment (ESC 2026, Class IIa, Level C).^[2][1][3]
• In Australia, NHFA/CSANZ 2025 says perform CABG at the time of surgery in STEMI or ACOMI with mechanical complications and mitral valve disease (strong recommendation, low certainty).^[6]