Introduction: To present a rare occurrence of “Swiss-cheese” defects of left ventricle in acute myocardial infarction. Case Report: A 64-year-old male with persistent ST segment elevation in anterior and inferior leads developed sudden deterioration 2 days after thrombolysis. Echocardiography revealed ventricular septal and LV (left ventricular) free wall ruptures at multiple sites with contractile dysfunction and the patient died suddenly followed by an episode of ventricular tachycardia. Discussion: Myocardial rupture may complicate in 10% of acute myocardial infarctions and it is the second most common cause of in-hospital mortality next to pump failure. It is responsible for 15% of in-hospital deaths and 50% die within 5 days and 82% die within two weeks of index infarction. Conclusion: Aggressive early diagnosis and surgery may confer a survival rate as high as 75%.  The prognosis is grave in patients presented with cardiogenic shock and multiorgan dysfunction, surgery is best avoided and supportive medical therapy may be adequate in such cases.

Left ventricular wall comprises three layers, superficial (subepicardial), middle, and deep (subendocardial) and the longitudinal alignment of myocardial strands of one layer interconnect with strands of next layer in continuum, not separated by cleavage planes or sheets of fibrous tissue. The superficial layer occupies approximately 25% of wall thickness and these oblique strands are in continuity with longitudinal strands of deeper layer at the base and apex of the ventricle, which constitutes < 20>

Table 1: (Becker and van Mantgem classification of myocardial rupture).

 Morphologically, four types of myocardial rupture have been described [6] as given in Table 2.

Table 2: (Morphological types of myocardial rupture)

Kumar, et al [7] reported cardiac rupture in Takotsubo cardiomyopathy, a reversible disease often triggered by acute emotional or physical stress, characterized by ECG changes mimicking acute myocardial infarction and acute complications such as cardiogenic shock occurs in 50 % of cases [8]. This can lead to left ventricular rupture and recent studies reported right ventricular involvement in 28-50% [9],[10], the friable right ventricle susceptible to rupture due to mechanical wall stress in biventricular Takotsubo cardiomyopathy [11]. Isolated RV free wall rupture as a complication of inferior wall and right ventricular myocardial infarction is an uncommon finding in transthoracic echocardiographic examination [12] and it was reported in Figures 15 to 20.

Review of literature: Historically, the first clinical reference to post-infarction left ventricular wall rupture was reported by William Harvey in 1647 [13]. London and London in an analysis of 1000 cases of fatal myocardial infarction found that 50% of ruptures occurred within 3 days and 89% within 14 days [14]. They reported that repeated and prolonged chest pain occurring in 55% of patients with cardiac rupture due to slow leakage of blood into the pericardial space prior to complete rupture and only in 10% of cases without rupture. An accumulation of 75 ml of blood is sufficient to produce cardiac tamponade and death in acute ruptures. The anterior wall of left ventricle is involved more commonly than the posterior wall [15]. Von Torsel and Edwards suggest that symptomatology was consistent with a gradual evolution of cardiac rupture in reviewing 40 cases [16]. Leutsch and Lanks demonstrated that the rupture was progressive rather than abrupt by finding an organizing thrombus at the site of rupture [17]. Common sites of myocardial rupture are anterior or lateral walls and a mid ventricular position along the apex to base axis is most frequent (66%). Blow-out and ooze ruptures are the other pathological variations sometimes used. Blow-out ruptures present as macroscopic tear in the epicardium and the 

communication between the LV cavity and pericardial space is observed. In oozing ruptures, no macroscopic defects are visible [18] Multiple sites of rupture in the left ventricular myocardium including the interventricular septum following an acute myocardial infarction is uncommon and so this case had been reported.

2.Case Report: A 64-year old hypertensive, non-smoker male was brought to the emergency room with shortness of breath and hypotension. He was drowsy and extremities were cold and clammy. He had a history of out of hospital thrombolysis with streptokinase 2 days before for a sudden onset of chest pain and elevated cardiac enzymes (Troponins and CK-MB). His pulse was feeble and blood pressure not recordable. Auscultation revealed a grade 4/6 loud, harsh systolic murmur with a palpable thrill over the left sternal border and apex, not conducted to axilla and back. Basal crackles were present over the lung fields. Renal and liver parameters were normal.  ECG revealed a persistent ST segment elevation simultaneously seen in anterior and inferior leads as shown in Figure 1. He was in cardiogenic shock and supported with intravenous fluids and inotropic agents. He subsequently developed an episode of ventricular tachycardia, triggered by inotropic agents and hypotension (Left posterior septal origin as evidenced by RBBB (right bundle branch block) morphology in V1 with right axis and changing contour of QRS complexes as RBBB morphology in V1, V2 and LBBB (left bundle branch block) morphology V4, V5 and negative deflection in V6 as shown in Figure 2) and it was not responded to intravenous amiodarone and cardioversion, the patient’s condition deteriorated and died suddenly despite resuscitative measures. Emergency Transthoracic 2D echocardiography revealed an anteroapical LV (left ventricular) aneurysm with multiple perforations of the interventricular septum and LV free wall as shown in Figures 3 to 14 with contractile dysfunction.

Figure 1: ECG (2 days after thrombolysis) showing persistent ST segment elevation in anterior and inferior leads (wraparound  LAD (left anterior descending coronary artery) occlusion.

Figure 2: ECG showing ventricular tachycardia of left posterior septal origin.

Figure 3: Apical Four chamber view showing the thinned, dyskinetic anteroapical septum with aneurysm [19].

Figure 4: Parasternal long axis view showing the thinned out anteroapical septum.

Figure 5: Tilted apical view showing the dilated, hypokinetic left ventricle.

Figure 6: Tilted apical view showing the multiple perforations of the apical septum.

Figure 7: Parasternal long axis view showing the anteroapical ventricular septal rupture.

Figure 8: Parasternal long axis view showing the flow into the left ventricle through the septal rupture.

Figure 9: CW (Continuous Wave Doppler) showing the bidirectional jet of ventricular septal rupture (VSR).

Figure 10: Apical four chamber view showing the basal septal rupture

Figure 11: Apical 3 chamber view showing the apicolateral  LV (left ventricular) free wall rupture.

Figure 12: Apical 3 chamber view showing the basal lateral LV (left ventricular) free wall rupture.

Figure 13: Apical 4 chamber view showing the “Swiss-cheese” left ventricle with multiple sites of ruptures.

Figure 14: M-Mode LV study showing the contractile dysfunction of the left ventricle with an ejection fraction of 26%.

Figure 15: 2D echocardiographic imaging showing the small RV (right ventricular) free wall rupture in a 66-year old female with acute inferior wall infarction in apical four chamber view.

Figure 16: Color Doppler imaging showing the RV free wall rupture into the pericardial space with effusion in a 66-year old female with acute inferior wall infarction.

Figure 17: Color Doppler imaging showing the RV free wall rupture with a shunt into RV cavity in a 66-year old female with acute inferior wall infarction.

Figure 18: 2D echocardiographic imaging showing the large RV free wall rupture in a 70-year old male with right ventricular infarction in apical four chamber view.

Figure 19: Color Doppler imaging showing the RV free wall rupture in a 70-year old male with right ventricular infarction.

Figure 20: Color Doppler imaging showing the RV free wall rupture with a dense doppler signal in a 70-year old male with right ventricular infarction.

Myocardial rupture is a catastrophic complication of acute myocardial infarction and most often occurs near the edge of the necrotic myocardium where it abuts the hyperemic healthy zone having the greatest inflammatory activity and high shear stress. It involves the free wall of the ventricles, interventricular septum, papillary muscles and rarely involves the atrial walls. It is more common in patients aged > 60 years and usually seen in women (1.4:1). Contributing risk factors for myocardial rupture are listed in Table 3.

Table 3: (Risk factors for myocardial rupture).

 Left ventricular free wall rupture is 4-10 times more often than the rupture of the interventricular septum or papillary muscle with an incidence of 2-4% of myocardial infarction [26],[27] and 2.2-10% in various series [28]. It was localized to anterolateral, anteroapical, inferolateral and posterior walls. Higher incidence of rupture (44%) in the lateral wall of the ventricles is probably due to the increased stress resulting from the contraction of papillary muscles. Postinfarction pericarditis manifested as pleuritic chest pain and friction rub may be present in some cases before the onset of left ventricular free wall rupture and indicates the transmural extension of the infarct. Early rupture (acute form) develops within first 48 hours and represents 40-60% of cases and the patients may die suddenly before reaching the hospital due to severe hypotension or electromechanical dissociation secondary to acute pericardial tamponade as a result of strain in the infarcted zone caused by sustained arterial hypertension (systolic blood pressure >150 mmHg) and ambulatory activity. In early rupture, there is hardly any thinning of the infarcted zone. Late rupture (subacute form) develops beyond the second day in an already expanded infarcted region and less affected by hypertension, but often triggered by undue physical efforts such as persistent vomiting and cough. It is less severe, more compatible with survival with an anfractuous tract between the layers of the myocardium and may account for 30% of all cases of in-hospital free wall rupture. Eventhough most of the ventricular ruptures occur in the free wall of the left ventricle [29], the rupture occurs in the interventricular septum in approximately 15 to 20% of cases [30] and it complicates 1-2% of acute myocardial infarction presentations in pre-thrombolytic era [31]. The incidence has declined to about 0.2% in thrombolytic era and most contemporary series shown that it is increasingly rare, complicating between 0.17-0.31% of patients presenting with acute myocardial infarction [32]. Two pathological types of ventricular septal rupture were described by Edwards et al [33] in an autopsy report as simple ruptures defined as direct through-and-through defects and complex ruptures characterized by serpigenous, hemorrhagic tracts with myocardial disruption and necrosis extending beyond the primary site with a convoluted course. Simple ruptures are more common after anterior myocardial infarction and complex ruptures are more frequent in inferior myocardial infarction. Of interest, 80% of all complex ruptures occurring in patients with inferior infarction and 21% of ruptures are complex in anterior myocardial infarction. The nature of presentation has changed as the average time interval between infarction and rupture is closer to 24 hours [34]. Ventricular free wall rupture (VFWR) in patients with reperfusion therapy (either primary PCI or thrombolytic therapy) occurs in 24-48 hours and is characterized by slit-like myocardial tear or erosion with hemorrhage due to 

activation of plasmin by thrombolytic agents [35] when the reperfusion time is delayed. About 60% of ventricular ruptures occur with infarction of the anterior wall, 40% with posterior or inferior wall and men are affected more commonly than women. Sometimes multiple septal perforations may occur simultaneously as shown in Figure 6 or within several days of each other. Acute onset of shortness of breath, chest pain, diaphoresis, unexplained emesis, cool and clammy skin and syncope may herald the onset of ventricular septal rupture in acute myocardial infarction. A triad of recurrent or persistent chest pain, recurrent or persistent ST segment elevation and unexplainable hypotension is termed as “subacute free wall rupture syndrome” (post-myocardial infarction free wall rupture syndrome) [36].  A loud, harsh systolic murmur, associated with palpable thrill in 50% of cases audible over left sternal border and apical areas is the most consistent physical finding of postinfarction ventricular septal rupture and it indicates the onset of sudden deterioration in a previously stable patient with the development of heart failure or cardiogenic shock. Persistent ST segment elevation after acute myocardial infarction is associated with higher incidence of myocardial rupture. In the setting of acute myocardial infarction, ST elevation in inferior and anterior leads as shown in Figure 1 as a result of occlusion of a large wraparound left anterior descending coronary artery (Left anterior descending coronary artery (LAD) reaching the apex, wraps around the left ventricular apex and travels some distance in the posterior inter-ventricular groove and supplying the apical inferior aspect of the heart – type III LAD) is associated with an increased risk of ventricular septal rupture [37]. New ST segment changes (“saddle-shaped ST-segment elevation”) or persistent non-inversion of T-waves in the affected leads may suggest a less noisy ‘stuttering” type of rupture [38]. Postinfarction septal defects are localized in the muscular part of the septum and are associated with a high incidence of left ventricular aneurysm as shown in Figures 3,4,5 [39] as 30

The free wall rupture in acute ST-elevation myocardial infarction is under-recognized [62] and sometimes it is subacute, may not be typical of an acute blow-out rupture and leading to death within minutes. Instant diagnosis is crucial to detect free wall ruptures by transthoracic echocardiography. The incidence of myocardial rupture was decreased if primary percutaneous intervention was performedin acute myocardial infarction [63] and it is about 2-3% [64]. If there is extensive myocardial damage with hemodynamic compromise, early intervention is urgently needed. Most studies show that overall mortality rate of early surgical approach is < 25>